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Old 08-29-2003, 02:13 AM
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21 Reasons why your engine may run Hot.




A lean air/Fuel Ratio (Also check fuel pump and Filter)
Too much timing/retarded timin/advanced curve malfunction
Clogged Radiator/Collapsed Hose (restricted water flow)
Clogged Engine (restricted water flow)
Stuck Thermostat / Incorect Thermostat
Bad Water Pump
Incorrect Water Pump Speed (too slow/too fast)

Radiator Too Thick
Wrong Pressure Cap
No Shroud Around Fan. Improper Fan Position Within Shroud.
Bad Fan Design - Stock Factory Type Usually Works Best.
High Volume or High Pressure Oil Pump
Electric Fan (Pullers/Pushers) Blocking Air Flow
Too Much Antifreeze
Wrong Type Antifreeze
Flow Test: Begin with cool engine. Remove radiator cap. Start engine. Bring engine up to operating temperature so that the thermostat opens. Increase engine speed to 2000 rpm. If water gushes out of radiator there is a flow restrictionin the system. This must be corrected for proper cooling.
Wrong Spark Plugs (ie. Heat Range)
Wrong Gasoline Type (Try 89 or 92 Octane)
Clogged Catalytic Converter.
Clogged Injector System.
Exhaust getting into the water due to a cracked head or blown head gasket. Have your local radiator shop test your system for carbon dioxide.

---------------------------
1967 Firebird 400 conv T400 3.08, 1989 Formula 350 700r4 3.27

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Old 08-29-2003, 02:13 AM
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interesting link


http://www.guyons.com/racing_tips6.html


21 Reasons why your engine may run Hot. More Racing Tips




A lean air/Fuel Ratio (Also check fuel pump and Filter)
Too much timing/retarded timin/advanced curve malfunction
Clogged Radiator/Collapsed Hose (restricted water flow)
Clogged Engine (restricted water flow)
Stuck Thermostat / Incorect Thermostat
Bad Water Pump
Incorrect Water Pump Speed (too slow/too fast)

Radiator Too Thick
Wrong Pressure Cap
No Shroud Around Fan. Improper Fan Position Within Shroud.
Bad Fan Design - Stock Factory Type Usually Works Best.
High Volume or High Pressure Oil Pump
Electric Fan (Pullers/Pushers) Blocking Air Flow
Too Much Antifreeze
Wrong Type Antifreeze
Flow Test: Begin with cool engine. Remove radiator cap. Start engine. Bring engine up to operating temperature so that the thermostat opens. Increase engine speed to 2000 rpm. If water gushes out of radiator there is a flow restrictionin the system. This must be corrected for proper cooling.
Wrong Spark Plugs (ie. Heat Range)
Wrong Gasoline Type (Try 89 or 92 Octane)
Clogged Catalytic Converter.
Clogged Injector System.
Exhaust getting into the water due to a cracked head or blown head gasket. Have your local radiator shop test your system for carbon dioxide.

---------------------------
1967 Firebird 400 conv T400 3.08, 1989 Formula 350 700r4 3.27

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Old 08-29-2003, 03:04 PM
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Nice post, good information...
Brad

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Old 08-30-2003, 01:58 AM
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glad it helped!

---------------------------
1967 Firebird 400 conv T400 3.08, 1989 Formula 350 700r4 3.27

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Old 08-30-2003, 01:44 PM
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Keep finding and posting good info like that as it is great reference material for the board.

Would like to have Chris set up a "Tips" section
some day when he revises the board again.

Tom V.


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Old 09-04-2003, 01:12 AM
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Thanks go to the
http://www.442.com

website. They have great reference and tech material also .

Dick Duclow also told me that block cement helps them to run cooler because it eliminates flexing. Talk to him for details.

Also think it is important to have proper factory sheet metal baffling and spoilers in place below radiator.

Also no thermostat may not allow coolant enough time to absorb heat. They make inserts with holes through them to slow down ccolant if you don't like thermostats. I'm no expert, but remember reading this in a magazine.

Might also want to check the divider plates inside our Pontiac water pumps. They can get holes in them due to corrosion. I dont think it will work properly with holes in it. PY sells stainless replacements.

Also radiator cap that is right pressure but is worn out and no longer holds same pressure. I think a sytem pressure check couldn't hurt.

Also check for fan on backwards if that is possible?

Did someone else change to underdrive pulleys? check pulley diameter and belt tension.

Check for worn out clutch infactory clutch type fan. I believe they are supposed to lock up at temp. Probably a good idea to replace this if bad or you are unsure.

Use another gauge to make sure your's is accurate.


On factory electric dual fan or single fan experts make sure the fans are actually working when they are supposed (read service manual)to or working at all. I had this problem n my 89 firebird with dual fans. one was dead the other was drawing too many amps. somone also makes a switch that uses bot fans nstead of just one at certain times.

I used distilled water because i figure it is less likely to leave behind mineral deposits. You can buy it at the grocery store. Make sure it says distilled not mineral water.

High load on auto trans or problem causng it to run to hot and dump more heat into system.

---------------------------
1967 Firebird 400 conv T400 3.08, 1989 Formula 350 700r4 3.27

[This message was edited by mike nixon on September 08, 2003 at 10:49 PM.]

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Old 09-04-2003, 02:18 AM
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also,

A correction to previous post you should use demineralized water not distilled since distlled is "mineral hungry" and may attack alum parts.



air bubble in system?


Air leaks on vacuum side of water pump allow air to get in to cause foaming and bubbling. leads to corrosion and insulates the block and radiator from the coolant. Visual inpection and pressure test to check for this.

Don't forget ignition timing and carburetion as mentioned before., dragging brakes, slipping clutch, and basically anything that adds heat into the system. Be sure to test for exhaust leaks into coolant as mentioned before. Either by a special kit to analyze CO from the radiator or alternately to disconnect water pump belt only briefly and observe to see if bubbles appear in coolant that indicates a leak or a hot spot.

Coolant recovery tank in good shape and hose still attached internally?

Has enginge been changed and original radiator is too small for job?

Excessive paint on radiator, damaged fins?

Thermostat installed upside down?


This website http://www.grapeaperacing.com/GrapeA...lings/heat.pdf has a very interesting write up
on the relationship of heat to power.

---------------------------
1967 Firebird 400 conv T400 3.08, 1989 Formula 350 700r4 3.27

[This message was edited by cscottfergus on September 04, 2003 at 05:31 AM.]

[This message was edited by cscottfergus on September 04, 2003 at 05:43 AM.]

[This message was edited by cscottfergus on September 04, 2003 at 05:49 AM.]

[This message was edited by cscottfergus on September 04, 2003 at 05:56 AM.]

  #8  
Old 09-04-2003, 03:03 AM
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more from grapeaperacing,



also be sure to do your own research to verify accuracy of anybodys recommendations.


http://www.grapeaperacing.com/GrapeA...oolingmods.cfm

Cooling System Goals

Most people seem to think that all a cooling system needs to do is keep the engine from overheating. But what is not realized is if the engine runs too cool, thermal efficiency is lost and power is reduced. Many will argue that an engine has more power when it is cold, but that is only due to the fact that the intake air is colder and denser, actual BSFC is higher. Remember that an engines whole job is to make heat and turn it into mechanical energy. Running the engine as hot as possible (limited by the coolant boiling point) will increase power and provide a lower BSFC. If the coolant begins to boil, steam pockets will form and detonation will limit power (by forcing you to retard timing to less than optimum or run the engine cooler). Most of today's high output street motors using a water/ethylene glycol mixture will be limited to a maximum of 200° F before detonation becomes a problem (unless other steps are taken). Another goal of modifying the cooling system is to even out the temperatures of the whole engine, which is not easy to do. All it takes is one hotter cylinder to run into detonation to limit the engines power. Most high performance engines are close to detonation to begin with, so a good cooling system is a must.

Nucleate Cooling Phase

As coolant flows through the system it absorbs heat from the parts it contacts. As it does this some of the coolant will boil and form tiny steam bubbles (absorbing a lot of heat) on the internal engine surfaces. When these bubbles get larger they become a flow restriction and the flowing fluid pushes them away from the surface and that process starts over again. This process is called the Nucleate Cooling Phase. When the coolant boiling point is too low or the flow rate is too slow, these bubbles can become too large and form steam pockets that insulate that part from being cooled. This usually happens around the combustion chambers. Once the steam pocket forms the surface can rise in temperature (even though the coolant is not overheating) and cause that part to overheat, which can cause detonation or other problems.

Types of Coolant

I'm sure that you've read or heard somewhere before that water is the best coolant. This is true as far as being able to absorb heat for a given flow rate, water does do that the best. Water also boils at a lower temperature than other coolants and can develop steam pockets easier, so it's not the best coolant in that respect. A water / ethylene glycol mixture will boil at a higher temp and resist steam pockets better than plain water, the down fall is that it has to have a higher flow rate, but that is easy to accomplish. The 3rd common (and least common) form of coolant is propylene glycol, which had the highest boiling point and can run higher than 250° F (average temperature as seen on a gauge) without forming steam pockets, but it must flow at more than twice the speed of a water / ethylene glycol mixture (which means major changes to most cooling systems).

System Pressure

The pressure in the block is higher than the radiator pressure, this is because the pump is building pressure due to the thermostat being a restriction. This pressure raises the boiling point of the coolant and reduces the chance of steam pockets, so never run with out a thermostat (or some form of restriction). The radiator cap will usually hold 15-18 psi, if the radiator holds the system at 15 psi, the boiling point of plain water will be raised to 250° F. The water pump can then make an additional 40-45 psi in the engine and bring that boiling point close to 300° F. So as you can see, pressure is important.

Stock Cooling Systems

Most stock cooling systems pull coolant from the radiator and push it through the each bank of the block, it then goes up through holes in the head gaskets to the heads and out the front of the heads to a common exit point. This ok for a stock engine that has no problems with detonation, but the cooling is very uneven. The front cylinders will run coolest and the front combustion chambers will run the hottest. Most stock pumps will also favor one bank. The stock pump used on a small-block Chevy for instance will always favor the passenger side bank. This means that cylinder 2,4,6 & 8 get more flow, so the 1,3,5, & 7 bank runs hotter. With the center exhaust ports right next to each other, you can see that combustion chambers 3 and 5 will run the hottest, it is in these two cylinders that detonation will usually first start. It seems a little backward to start the coolant at the block instead of the heads; it would make more sense to bring the coolest coolant to the hottest parts first. This type of reverse flow system has been tried with much success, but it is harder to get it working properly and not worth it for car companies to research when the stock system worked good enough on a stock engine.

Water Pumps

As I said before, stock pumps rarely flow evenly between banks. On the small-block Chevy you can restrict 1/2 of the block inlet to the even cylinder bank to get more even flow, but the better solution is to use an aftermarket high volume pump that has worked out such problems. Stock pumps have a stamped steel impeller and tend to cavitate easily when turned more than 6000 rpm, so overdriving the stock pump offers little to no advantages and can actually aggravate any cooling problems. Most aftermarket pumps will use a cast iron or an aluminum impeller that better resists cavitation. Weiand, Howard Stewart and Milidon make very good water pumps for most popular applications, which improve flow, resist cavitation better, and require less power to drive than stock pumps.

Electric Water Pumps

Many aftermarket companies offer electric water pumps. These pumps do not flow well or build sufficient pressure in the block. They are only good for limited drag racing use, and when used they need a high pressure cap to help prevent steam pockets. At best these pumps can flow 30 GPH and only build about 5 psi in the block. An electric pump should never be considered on a street or any type of endurance engine.

Coolant Flow

Different coolants require different minimum flow rates, but contrary to popular belief, you cannot make the coolant flow too fast. This rumor was started because people removed the thermostat to gain flow, because they had an over heating problem, and it aggravated the problem. The real reason they ran into problems is that removing the thermostat also removes the restriction that builds pressure in the engine, so they gained flow, but reduced the boiling point of the coolant in the block. Running a higher flow thermostat and a higher volume pump to maintain pressure, will give no such problems. If you think about it, making the coolant flow twice as fast will also make it flow though the engine twice as often, so there will be more even temperature across the engine.

Basic Flow Modifications

Most stock systems will have a common outlet for both banks. The outlets of each bank flows directly at each other than must take a 90° turn to return to the radiator. If one side gets hotter (which is sure to happen) the pressure of that side will increase. The increased pressure will increase flow in the hotter bank and decrease flow in the cooler one. The faster moving coolant will cool the hot bank better and the slower moving coolant picks up more heat in the colder side. As you can see, the hot side is getting cooled and the cooler side is heating up. This happens until the banks reverse, the side that was cooler is now hotter and has more pressure. The cyclic flow will continue until the engine is shut off. Smokey Yunick was the first to do studies on the cyclic flow and traced the problem to the outlet. By tapping the front of the heads, and bringing the coolant together in a Y eliminated the cycling.

Radical Modifications

To truly equalize temperatures throughout the engine, you must start fresh and build totally custom cooling system. The first step is to tap off the pump and put coolant to the back of the block so the coolant enters at both ends. This helps equalize the cylinder temperatures, but the heads will still be hotter toward the front. To equalize the head temperatures you must tap outlets at the back of the heads so that all the coolant does not have to pass the front combustion chambers. To further equalize, you can tap inlets and outlets in the center of the block and heads also. At that point the coolant will be flowing basically from bottom to top and is about the best you will get without reversing the flow.

Reverse Flow Systems

As I said earlier, it makes sense to put the coolest coolant to the hottest parts first to bring the temperatures down as much as possible, the already heated coolant can help bring the temperatures of the coolest parts up and make everything more even. To do this the coolant must flow in reverse (compared to most systems). The problem with reverse flow systems is that the pump tends to cavitate easier (even with a good aftermarket pump). To limit cavitation, a higher boiling point of the coolant helps and so does a higher system pressure.

---------------------------
1967 Firebird 400 conv T400 3.08, 1989 Formula 350 700r4 3.27

  #9  
Old 09-04-2003, 03:16 AM
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coolant article

http://www.babcox.com/editorial/tr/tr110046.htm



Under The Cap, Larry Carley, Tire Review, November 2000
Today's Coolant Options Require Close Attention, Different Techniques

When you open a radiator cap these days, you're never quite sure what you're going to find. Antifreeze chemistry has undergone some significant changes in recent years, and the familiar green antifreeze long used in most vehicles is being replaced with a spectrum of not-so-familiar antifreezes that range in color from red to orange to pink to blue.

So it's important to know what type of antifreeze is in the system so you can add a compatible coolant, or replace it with one that provides equivalent or better protection.

Ethylene Glycol
Ethylene glycol (EG) has been the main ingredient in almost all automotive antifreezes for many years, and will continue to be for the foreseeable future. Straight ethylene glycol freezes at about 8° F, boils at 330° F, and carries heat about 15% less efficiently than water. But when mixed in equal parts with water, it creates a coolant well-suited to year-round driving for most applications.

The recommended 50/50 mixture of EG and water provides freezing protection down to -34° F and boilover protection to 265° F in a radiator with a 15 psi cap. If the proportion of antifreeze to water is increased to 70% EG and 30% water, the freezing point drops to -84° F and the boiling temperature goes up to 276° F. Mixtures greater than 70/30 are not recommended because the coolant's ability to carry heat declines as the proportion of antifreeze increases.

Straight EG antifreeze should never be used in an engine because it may allow the engine to overheat. Likewise, straight water should never be used because it provides no freezing, boiling or corrosion protection.

Propylene Glycol
Another base ingredient that is used in place of EG in some aftermarket antifreezes (like Prestone's LowTox and Safe Brands' Sierra antifreeze) today is propylene glycol (PG). The coolant's thermal characteristics are similar to those for EG: a 50/50 mixture of PG and water provides freezing protection down to -26° F and boilover protection to 256° F. If the coolant mixture is increased to 60/40, coolant freezing protection goes down to -54° F.

The main advantage of PG compared to EG, however, is that it is considered nontoxic to animals. That doesn't mean it is safe to drink, but it greatly reduces the risk of poisoning a pet.

Pure PG boils at 370° F and provides freezing protection down to -70° F, so it is sometimes used straight without any water at all as a coolant in racing applications. Running PG straight provides better cooling because there is no water to vaporize in hot areas of the cylinder. This also allows the use of very low pressure or even no pressure cooling systems.

While PG and EG are both compatible and can be intermixed without affecting cooling performance, intermixing the two different antifreezes is not recommended because doing so defeats the reduced toxicity advantages of PG. Also, if a vehicle's cooling system is filled with an extended life EG coolant, adding PG - not currently formulated for extended service - will reduce the service life of the coolant mixture to that of a conventional green coolant.

Intermixing PG and EG antifreeze also makes it impossible to get an accurate indication of the coolant's strength if you're using a hydrometer to check coolant concentration. The specific gravity of EG and PG are different, so a mixture of the two will usually indicate a lower freezing point than the coolant actually provides.

The best way to determine the concentration of PG in uncontaminated coolant (no EG present) is to use a refractometer. The reason is because the specific gravity of PG increases up to about a 70% concentration, then falls off considerably. Consequently, a 100% PG solution will read the same as a 45% solution on a hydrometer.

General Motors and others approve PG as an acceptable replacement coolant, but if making a change it's important to remove all of the old EG coolant before adding PG to the system.

Corrosion Inhibitors
Because coolant is in constant contact with the metal parts of the engine and radiator, some type of corrosion inhibitors must be used in the antifreeze to protect all metal surfaces from electrolysis. That includes cast iron, steel, aluminum, brass, copper and lead solder.

Most conventional antifreezes formulated for the North American market, whether green or yellow in color, contain inorganic salts of borate, phosphate and silicate to prevent rust and corrosion. The additives create an alkaline coolant mixture that typically tests at about 10.5 on a pH scale. The silicates form a protective coating on metal surfaces, and are especially good at protecting aluminum.

To ensure that coolant remains alkaline for a reasonable length of time, there must be enough corrosion inhibitor to neutralize the acids formed from glycol degradation that occurs over time. This neutralizing capability is called "reserve alkalinity," and it varies depending on the type and quantity of additives used in a particular brand of antifreeze.

Heat, dissolved oxygen, minerals in the water, and corrosion inhibitor reactions at the metal surface gradually use up the corrosion inhibitors. And once depleted, the coolant becomes acidic and corrosion accelerates. The secret to preventing internal corrosion, therefore, is to change the coolant before all the reserve alkalinity has been used up.

Periodic coolant changes are especially important with today's bimetal engines and aluminum radiators and heater cores because the different metals create a miniature battery cell that promotes electrolytic corrosion. Aluminum becomes the sacrificial anode, iron the cathode, with the coolant serving as the charge-carrying electrolyte.

The higher the percentage of dissolved minerals and salts in the coolant, the better it conducts electricity and the faster the aluminum is eaten away. As long as the corrosion inhibitors are working, the process is held in check. But once they're used up, corrosion starts to eat away. The most vulnerable components are usually the thinnest, which include the radiator and heater core.

The Effect of Air & Water
Other problems can also accelerate the breakdown of the coolant. An exhaust leak into the cooling system through a cracked head or leaky gasket will quickly destroy reserve alkalinity in the coolant because oxygen reacts with the additives in the antifreeze. If an engine has a leaky head gasket, don't reuse the old antifreeze when the gasket is replaced.

The amount of additive needed to protect the cooling system isn't much - only about 2% to 3% of the total liquid in the jug. This is usually enough to protect for at least two years or 30,000 miles in most vehicle applications - or even longer if the antifreeze is mixed with relatively pure water (distilled or deionized).

Some say ordinary antifreeze can go as long as five years or 100,000 miles before the corrosion inhibitors are fully depleted - provided pure water is used to fill the system, the cooling system was relatively clean when filled (no accumulated rust or scale), and the coolant level is kept full with no air entrapment.

Hard water that contains high amounts of calcium and magnesium can react with phosphates in the additive package to form sediment and scale. That's why European vehicle manufacturers use antifreezes that contain no phosphates (hard water is common in Europe). European antifreeze may be dyed blue, yellow (Mercedes) or pink (VW and Audi).

Tap water in North America also contains calcium, but isn't as hard as European tap water so phosphates are considered okay to use here.

Under no circumstances should softened water be used in a cooling system because softened water substitutes sodium (salt) for calcium. Sodium is very corrosive to all metal surfaces and undermines the corrosion-inhibiting abilities of the additives.

The Japanese and other Asian vehicle manufacturers, by comparison, prefer an additive package that contains phosphates and other inhibitors but no or low silicates. Japanese coolants may be dyed red, but some newer blends are dyed green.

According to the aftermarket antifreeze suppliers we interviewed, using a typical green antifreeze formulated for North American domestic vehicles in European or Japanese vehicles should cause no problems. The basic metallurgy is the same so the degree of protection provided should be the same: two years or 30,000 miles.

OAT Technology
The latest corrosion inhibiting additives are based on a different chemistry called Organic Acid Technology (OAT).

Antifreezes with OAT corrosion inhibitors contain organic acid salts of mono- and dicarboxylic acids such as sebasic and octanoic acids, plus tolytriazole. The coolant is less alkaline and protects with a pH reading of only about 8.3.

Brands with the OAT additive package include Texaco/Havoline's Dex-Cool and Prestone's Extended Life 5/150 antifreeze. OAT coolants contain orange dye to distinguish them from other coolants with conventional additive packages.

The main advantage of OAT technology is extended service life: up to five years or 150,000 miles. But to achieve this length of service, the OAT coolant must not be intermixed with any other type of antifreeze. If the system is topped off with ordinary green antifreeze, the corrosion protection will be reduced to that of a conventional coolant, say the coolant makers.

GM was the first domestic vehicle manufacturer to make the switch to OAT coolants, starting in 1995. Since 1996, all new GM cars and light trucks have been factory-filled with orange Dex-Cool coolant.

GM says Dex-Cool can be used in older vehicles provided the cooling system is first flushed to remove all traces of conventional coolant. But people have said OAT-based coolants do not provide adequate protection for vehicles with lead-soldered copper/brass radiators - a charge the makers of OAT antifreeze say is not true. Texaco/Havoline and Prestone both say their products meet or exceed the ASTM D-2570 standards for corrosion protection.

Sowing OATs
There has been some controversy regarding the use of OAT coolants because of sludging problems GM experienced in some 4.3L S10 truck engines. GM service bulletin #99-06-02-012 says the sludging problem is caused by air pockets in the cooling system from failing to maintain the coolant level or not getting all the air out the system when refilling the cooling system.

GM's fix for the condition is not to switch back to a conventional coolant (which some people advocate), but to flush the system repeatedly until all the brown sludge has been removed. The system can then be refilled a 50/50 mix of Dex-Cool and clean water.

Despite the problems with the 4.3L truck application, the use of OAT antifreeze is expected to grow. DaimlerChrysler introduced its own extended service OAT hybrid coolant for passenger cars in 1998. Unlike Dex-Cool, the DaimlerChrysler coolant contains silicates for extra aluminum protection. DaimlerChrysler, however, does not recommend using their OAT hybrid in older vehicles.

Ford in North America is still using conventional additives in its antifreeze, with the exception of the 1999 and up Mercury Cougar which now uses an OAT coolant. But Ford of Europe has switched over to OAT antifreeze for many of its vehicles. Truck manufacturers including Navistar, Mack and Caterpillar have also approved OAT.

Coolant Checks Important
One problem we have in is that we have no way of knowing what kind of antifreeze is in a customer's cooling system when it comes into the shop. It may be the factory-fill coolant, it may be an aftermarket coolant, it might be a propylene glycol coolant, or it might be a mixture of several different types of coolants.

If you don't keep these possibilities in mind, a simple coolant check with a hydrometer may give you a false indication of the strength of the coolant. A refractometer is a better tool to use because it doesn't measure specific gravity but how the liquid bends light.

Chemical test strips are available to check both the concentration and condition of the coolant, too. But test strips designed for conventional green coolants won't give an accurate indication of the coolant's condition if used with an OAT type of coolant.

Coolant Service Tips
Though most coolant service consists of flush and fill, ethylene glycol coolants can also be recycled using the proper equipment (see sidebar below).

Recycling has obvious environmental benefits, and can be a source of additional profits for your tire store. EG coolants with OAT additives can also be recycled, but the aftermarket additives currently available only return the coolant to a standard two-year/30,000-mile silicate coolant.

When refilling a late model GM vehicle that was factory-filled with Dex-Cool, you have to decide what type of coolant to use. According to GM, Dex-Cool is the only acceptable coolant. But once the vehicle is out of warranty, there's no reason why you can't use another brand of OAT coolant or a conventional EG or PG coolant, say the makers of these products.

The same goes for using an OAT coolant in an older vehicle that contains a conventional green coolant. If the system is thoroughly flushed, you can give your customer the extended service benefits that an OAT coolant provides.

OAT coolants can also be used to refill European and Asian vehicles, provided the system is first flushed to remove all traces of the old coolant.

The National Automobile Radiator Service Association (NARSA), however, is more cautious about the use of OAT coolants. NARSA says OAT coolant should not be used in any Ford product (except the 1999 Cougar) or Chrysler vehicle because there is a risk of water pump cavitation erosion. GM reportedly redesigned its water pumps to eliminate cavitation erosion.

Regardless of what type of coolant is used to refill a cooling system, the system should be cleaned if sediment, rust or scale are present. Also, the system should be pressure tested to make sure there are no leaks. And don't forget to pressure test the radiator cap, and inspect the belts and hoses, too.

Refilling some of today's vehicles can be tricky if the heater core or other hoses are higher than the radiator cap. If the system has bleeder valves, use them. If it doesn't, it may be necessary to jack up the front of the vehicle so the radiator cap is the highest point in the system.

---------------------------
1967 Firebird 400 conv T400 3.08, 1989 Formula 350 700r4 3.27

  #10  
Old 09-04-2003, 03:27 AM
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someone poured radiator stop leak in sytem and stopped it up?

correction should have typed yours three posts up instead of your's, sorry.

---------------------------
1967 Firebird 400 conv T400 3.08, 1989 Formula 350 700r4 3.27

  #11  
Old 09-04-2003, 12:00 PM
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another reason

Pistons too far below zero deck height. making it more likely to detonate. For more on this read..
Jim Hands compression article

I found this article by Jim Hand especially informative and reading it may give you insight.
http://www.boyleworks.com/ta400/psp/compression2.html



---------------------------
1967 Firebird 400 conv T400 3.08, 1989 Formula 350 700r4 3.27

  #12  
Old 09-04-2003, 04:34 PM
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hi stall speed torque converter without external trans cooler( call professionals on this one).

---------------------------
1967 Firebird 400 conv T400 3.08, 1989 Formula 350 700r4 3.27

  #13  
Old 09-04-2003, 04:46 PM
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Us radiator diagnostic equpment

http://www.usradiator.com/diagnostic.htm


Diagnostic Equipment

We've included in this catalog for the first time a line of field test equipment (section 17) that we use when analyzing cooling system performance. Most of the items are available through industrial hardware distributors and rarely sold outside the trade. They are not for everyone but it seems every time we use these items at car shows to analyze an overheating problem someone tries to buy them from us.

We particularly like the air-flow meter better known as an anemometer since overheating occurs at low speed or idle and can be directly related to air-flow. The other item we always carry with us to car shows is a digital readout temperature gun. Both items are handy instruments for the enthusiasts and simply a must for the pros.





Digital Thermo-Anemometer

If your car runs cool at 30 MPH plus, but heats up at idle or low speed, chances are you have an airflow problem. Changing fan blades, adding shrouds, airdams or electric fans can help but, measuring the actual improvement requires the proper equipment. Our new Digital Thermo-Anemometer allowing the pros and hobbyist alike to see and measure airflow increase step-by-step during the modification process.
We now offer a high quality digital instrument which measure air flow in...MPH, Km/Hr., Meters/Sec. or Knots while measuring the temperature in either C° or F° at the same time. A must for professional car builders and a true time and money saver for the hobbyist. Unit comes complete with monitor, cord and hand held measuring fan. Batteries not included.




Digital Flow-Meter
We now offer in our complete line of cooling diagnostic tools, instruments designed to help professionals better understand cooling system failures. Our new Digital Flow-Meter quickly and accurately measures coolant flow in gallons per minute at various RPM's while testing the vehicle in a garage or on a read test (this unit is portable and can be used while driving your vehicle). Obvious mechanical failures such as worn bushings and seals are easy to see and diagnose, but inadequate flow and cavitation caused by worn impellers can only be revealed by accurately measuring the cooling flow while the vehicle is running a t idle or test driven. The battery operated Digital Flow-Meter is light weight and portable with an easy reading lighted dial. unit comes complete with a 1-1/2" I.D. connection, wiring harness and easy calibration procedures. Installation is simple, unit plumbs directly into top radiator hose with wiring harness plug-in. The length of wires on the harness will easily reach from vehicles engine compartment to inside most vehicle cabs. Batteries not included.




Digital Temperature Gun
Last but not least we have now added a battery operated hand-held Digital Temperature Gun to our line of cooling diagnostic tools. The temperature gun is designed to give accurate, instant temperature readings. Professional car builders and hobbyist alike will find many uses for this new infra-red gun including, temperatures for sticking thermostats and for checking radiator cores for hot spots which would indicate blockage. Unit is hand held, light-weight and portable with a lighted dial for easy reading. Batteries not included

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1967 Firebird 400 conv T400 3.08, 1989 Formula 350 700r4 3.27

  #14  
Old 09-08-2003, 02:12 PM
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more:

clogged or restricted exhaust/

wrong cylinder head gasket? or installed incorrectly

centrifugal advance fails due to sticking weights

slipping belt

leaking water pump seal(allows air in)

build-up of scale in block

idle speed too low

antifreeze concentration over specification

You are producing more heat than the system was designed to handle?

not enough coolant in system

casting flash blocking cooling passages

oil or grease in the coolant will affect heat transfer

alcohol based antifreeze in mild weather


From Motor trouble shooting guide:
Six basic causes for overheating water cooled engine:
1. water not cooling engine
2. Air not cooling water
3. Pre-ignition
4. Pinging
5. excessive friction in engine or powertrain
6. excessive backpressure in exhaust system

---------------------------
1967 Firebird 400 conv T400 3.08, 1989 Formula 350 700r4 3.27

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Old 09-12-2003, 02:54 PM
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A post and reply from the first generation firebird list on cooling issues



"
Subject: RE: [FGF] Drove car home...overheated...saga
From: "Brent Block" <Block.Brent@spartan.ab.ca>
Date: Thu, 11 Sep 2003 16:35:00 -0600

Hi Dan,

Niklas Ridell posted this a while ago and it is a very good summary of what
to check for when dealing with overheating problems. I've added my $.02
worth. The Pontiac 400's and cars with A/C were equipped with upper
(X-pans) and lower air baffles to tunnel the air through the rad. Front
spoilers also help to direct air into the radiator. Your temperature light
should go on at roughly 140-150 deg. If you are boiling over and your rad
cap is sealed you are probably exceeding these temps and that is not good.

I hope this helps

Brent Block
Edmonton,Alberta,Canada
****************************************** Snip
************************************************** ********************

Thermostat missing:
Will not help cool the engine. Is also an aid for circulation.
( Use a 195 deg stat in your Pontiac. It allows the coolant to stay in the
radiator longer and helps the system cool the motor more efficiently.
Removing the thermostat and not installing a restrictor plate is a sure way
to heat up the motor)

Thermostat stuck:
Unusual but might happen. Replace thermostat.

Radiator clogged:
Remove and clean out.
( A flow test is an easy way to check this)


Radiator not sufficient size:
All replacement radiators today are 4-row. Adds about one gallon of water
compared to 3-row.

Engine block clogged:
Remove freeze plugs, clean out with pressurized water. Don't forget threaded
plugs.

Heater clogged or leaking:
Clean out and replace if needed. But keep it connected! Nearly half a gallon
or 10% of the cooling system is here.

Correct anti-freeze mixture:
Mix 50/50.
( I use a 60/40 glycol to water mix, A product called wetter also helps
cooling and lubrication)

Wrong radiator cap:
There has to be correct pressure in your system. 60-71 models with
integrated expansion tank 12-15psi. Later cars with external expansion tank
shall have 15-17psi, which also gives you a higher boiling temperature.

Broken radiator cap:
The rubber seal is broken and doesn't seal. This gives you wrong pressure
and temperature.
( Higher pressure equals higher boiling point)

Too low water level:
Doesn't need an explanation...

Too high water level:
Common error, gives too high pressure and the water is ejected out of the
system without boiling. The radiator should be cold when filled. Check the
level marks at the side of your radiator tank.
( Level is about 1-2" below top of rad, An air lock in the system will also
give you problems. Run the car for a few minutes with the cap off until the
water circulates w/o seeing any air bubbles. Top up as required.)
Fan:
Another common culprit. 95% of the aftermarket flex fans are made for
smaller engines. Crap!


Fan:
Cars with A/C and most performance engines have a big 7-blade fan with
thermostat clutch. Good!

Fan clutch:
If it's old and the condition is unknown -replace it. It's hard to find out
if it's working properly or not. If you can turn it by hand after you have
stopped the engine it's definitely shot.

Too lean fuel/air mixture:
Makes it hot. Time to check what jets/carburetor you have.

Too retarded ignition or broken vacuum pot on distributor:
Makes the engine work harder and overheats.
( Retarded timing equals pre-ignition, Exhaust valves are not open enough
when engine fires and heat is trapped in engine)

Vacuum leak:
Intake/carb/rotted hoses/brake booster. Makes the engine run lean and hot.

Poorly adjusted valves:
This should be noticed on crappy running engine. Burned valves generates
heat (exhaust).

Water pump:
Broken/leaking/rusted.

Circulation plates '64-'68:
Behind the water pump. Two pieces! Creates a "housing" for the circulation.
Common error.

Circulation plates '69-'79:
Behind the water pump. One piece! Check also the pipes in the timing cover.
Common error.
( Also I have seen replacement water pumps with small useless blades or
broken pieces. Use a genuine GM replacement pump)

Lower radiator hose:
Tricky error. Original it has a spring inside that prevents the hose to
collapse. If the spring is rusted the hose will collapse when the engine is
revved and stop the flow.
( Some people make the mistake of installing a lower rad hose w/o the inner
wire coil. This creates the straw effect and cuts off circulation at higher
speeds or when engine is revved)

Cylinder head seal:
If the engine builds up a pressure, smokes white, bubbles in the radiator.
Problems.

Engine block cracked:
Same symptoms as above and also oil in the cooling water.

Cracked cylinder heads:
Same symptoms as above. Very rare on Pontiacs.

Cylinder head freeze plugs:
You didn't put them in the wrong position? Might block the water jackets.

Timing cover oxidation:
Not so unusual actually. Gives bad circulation and overheats.

Fan shroud missing:
Helps engine cooling at low rpm's and cruising speed. A must have.
(Also having the proper fan shroud installed with the fan 1/2 in and 1/2 out
(correct position) creates maximum air flow and proper cooling.


Subject: Re: [FGF] Drove car home...overheated...saga


First Generation Firebird-L Mailing List
.................................................. .......................
Dan,

A few suggestions:

1- Add a temp guage and oil pressure guage, PRONTO! Don't trust idiot
lights.

2- Check/set timing with a timing light

3- Make sure you're not running too lean. Adjust the idle mixture.

4- Replace the thermostat (I like the 160 degree ones. Other people like the
hotter ones)

5- Replace the water pump

6- Rebuild/replace the radiator. I've had great luck with the Desert Cooler
and they are not that expensive (through Ames)

7- At 70 MPH the fan/fan clutch don't help much, however, make sure that the
filler plates are on the top in front of the core support and that you have
a good fan shroud. There are also some rubber fillers that sit in front of
the radiator that make sure air flows through it. All this helps guide the
air through the radiator and not around it.


Subject: [FGF] Drove car home...overheated...saga


>
> I need help troubleshooting the overheating so that I
> can have everything done by the guy who is doing the
> engine.
>
> Thanks.
> Dan"

---------------------------
1967 Firebird 400 conv T400 3.08, 1989 Formula 350 700r4 3.27

  #16  
Old 07-25-2010, 02:47 PM
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Found out today that a vacuum leak in fact WILL cause your vehicle to run Warmish!!! Great posts!!!

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Old 07-25-2010, 11:06 PM
Pontirag Pontirag is offline
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And spending alot of money on aluminium radiator does not fix anything.

  #18  
Old 07-26-2010, 07:24 AM
rad400 rad400 is offline
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I think this thread should be a sticky. good information.

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  #19  
Old 07-27-2010, 01:24 AM
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Quote:
Originally Posted by rad400
I think this thread should be a sticky. good information.
I dunno,all that writting and it completely ignores trapping air in a closed cooling system.

That's one malady I see trip up a whole lotta people...



Bret P.

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  #20  
Old 08-06-2010, 09:25 PM
ELKHORNAOG7 ELKHORNAOG7 is offline
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Would it be wise to use a radiator flush if you were going to change to a different anti-freeze-----BOB

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