[fiesta62]

hi, my 67 gto sits on 190 driving but as soon as i sit and idle the temp goes up, today in traffic temp went to 215 before i got moving again, if i had to wait longer it would keep going up etc, i have had the water pump modified to flow better, also installed a new pully to spin pump faster, installed aluminium manifold which should help cooling, installed a coolant recovery tank, and just replaced fan clutch with the hayden severe duty, when i bought car receipts show the harrison rad has been recored with a max flow core , i could install a aluminium rad but thinking that may not change anything as my rad looks fine, i have a hi flow 180 thermostat installed, i thought about electric fans but many seem against this idea so what can i do, any ideas? thanks

[72LuxuryLeMansLa.]

Originally Posted by fiesta62

hi, my 67 gto sits on 190 driving but as soon as i sit and idle the temp goes up, today in traffic temp went to 215 before i got moving again, if i had to wait longer it would keep going up etc, i have had the water pump modified to flow better, also installed a new pully to spin pump faster, installed aluminium manifold which should help cooling, installed a coolant recovery tank, and just replaced fan clutch with the hayden severe duty, when i bought car receipts show the harrison rad has been recored with a max flow core , i could install a aluminium rad but thinking that may not change anything as my rad looks fine, i have a hi flow 180 thermostat installed, i thought about electric fans but many seem against this idea so what can i do, any ideas? thanks

Do you have a quality radiator cap that keeps the coolant system at around 15-17PSI? I just had to replace my cap because it allowed the boiling point to drop due to lack of pressure. I prefer this model: http://www.stant.com/modules/partLoc...m.cfm?id=10230

Also... Did you verify the thermostat opening temps in a pot with a thermometer before install? They have been known to be bad in the box.

You didn't mention a fan shroud; do you have one installed correctly?

Karl

[Old Goat 67]

Originally Posted by fiesta62

hi, my 67 gto sits on 190 driving but as soon as i sit and idle the temp goes up, today in traffic temp went to 215 before i got moving again, if i had to wait longer it would keep going up etc, i have had the water pump modified to flow better, also installed a new pully to spin pump faster, installed aluminium manifold which should help cooling, installed a coolant recovery tank, and just replaced fan clutch with the hayden severe duty, when i bought car receipts show the harrison rad has been recored with a max flow core , i could install a aluminium rad but thinking that may not change anything as my rad looks fine, i have a hi flow 180 thermostat installed, i thought about electric fans but many seem against this idea so what can i do, any ideas? thanks

62,

Don't know your name, but would like to.

First, you need to know that these cars did not have overheating problems originally. Second, without spending wasted dollars, they will run cool today. Aluminum radiators and electric fans are just expensive eye candy to some, IMO.

Case in point is that both Karl & I live in Louisiana (HOT country), we both have cars that run cool with AC on in the HOT country!

You can (and probably have) read many threads about trying this and that, all the time spending many bucks for little or no gain! Frustrating I imagine for many.

IMO, you have to systematically drill down to the root cause analysis.

Number one, DO you really have a heat problem? IE, is it really hot? How are you reading this temp? What gauge do you have? Is it calibrated dead on and have you verified it with an IFR gun? Get us some IFR readings at key places in the cooling system, IE thermostat housing, upper & lower hoses at radiator, front & rear of heads, etc.

I can tell you this with certainty, my 67 is all stock from factory with the exception of a re cored radiator and a 180° Stant thermostat and it will NOT go over 193° on the hottest days with the AC on. Karl's car is about the same, I believe.

You need to give us more info so we can try to help you get it right.

It all comes down to proper water flow and air flow.

I read where you have clearanced the pump, but that causes me concern every time I hear it. What is the real configuration of the impeller to the plates over the curve of the two? IMO, that is the single greatest problem area of cause of overheating. Attached is a picture of my water pump showing what I am talking about. Notice how it matches the plate across the curvature of the vanes all the way. It will not have cavitation when it fits as such. It will move water good which you can verify with the cap off and looking down into the radiator. But, if it is close in the middle and wide at the outside because of an impeller that is flat on the top of the vanes, good luck with that!

Many other factors to be sure, but you need to drill down to the real cause first.

Get us some more data so we can try to help you correctly.

Charles

[mchell]

if you tried everything else....get a radiator........a good one.....once I replace my old aluminum radiator that "looked good" with a new griffin with 1.5 inch tubes it dropped my temps by 50 degrees...I messed around for years before that

[fiesta62]

Originally Posted by mchell

if you tried everything else....get a radiator........a good one.....once I replace my old aluminum radiator that "looked good" with a new griffin with 1.5 inch tubes it dropped my temps by 50 degrees...I messed around for years before that

yes i have been thinking of new rad but as mine has receipt for the recored max flow , whatever that is, so i am holding off as my rad is probably ok, i have replaced many things on this car just to be sure, but usually find that the part i am replacing is already near new, i looked at griffin rads but was not keen on the epoxy they use , i figure if its welded correctly why use epoxy so i looked at the US radiator desert coolers though as u say griffin worked for u , i might relook at them, but still just not sure its going to help but it may be my only hope, thanks

[67GTONUT]

Take a breath.... and go back to basics.

Get us the specs on your car....

Something as simple as Ignition timing can be the cause of your issues.....

[Old Goat 67]

Throwing money at it won't fix it.

[fiesta62]

Originally Posted by 72LuxuryLeMansLa.

Do you have a quality radiator cap that keeps the coolant system at around 15-17PSI? I just had to replace my cap because it allowed the boiling point to drop due to lack of pressure. I prefer this model: http://www.stant.com/modules/partLoc...m.cfm?id=10230

Also... Did you verify the thermostat opening temps in a pot with a thermometer before install? They have been known to be bad in the box.

You didn't mention a fan shroud; do you have one installed correctly?

Karl

i just installed a new quality cpc brand recovery cap it has a stepped rubber seal underside, even though the 67 didnt have a recovery tank originally the cpc catalog listed this cap as the correct one to use, it is 13 psi which i notice is lower than you said to use so maybe this is a concearn, though i had the heat issue before i installed the mezier recovery tank.
i installed a new 180 high flow thermostat , i tested it and my old one in a pot of water on the stove both opened ok , i didnt have a thermometre but my old thermo was only a few months old and then i bought the new one to be sure, so i doubt its a thermostat problem
i do have the factory fan shroud fitted

my car sits bang on 190 driving around the local suburb so thermostat would be open, its only if i sit in traffic not moving for 5 minutes or more that temp will go up to 215 and i guess higher if i sat longer....25 degrees in 5 minutes , at a normal traffic light stop it dont change, it does need a good 5 minutes or more to start going up...

[fiesta62]

Originally Posted by Old Goat 67

62,

Don't know your name, but would like to.

First, you need to know that these cars did not have overheating problems originally. Second, without spending wasted dollars, they will run cool today. Aluminum radiators and electric fans are just expensive eye candy to some, IMO.

Case in point is that both Karl & I live in Louisiana (HOT country), we both have cars that run cool with AC on in the HOT country!

You can (and probably have) read many threads about trying this and that, all the time spending many bucks for little or no gain! Frustrating I imagine for many.

IMO, you have to systematically drill down to the root cause analysis.

Number one, DO you really have a heat problem? IE, is it really hot? How are you reading this temp? What gauge do you have? Is it calibrated dead on and have you verified it with an IFR gun? Get us some IFR readings at key places in the cooling system, IE thermostat housing, upper & lower hoses at radiator, front & rear of heads, etc.

I can tell you this with certainty, my 67 is all stock from factory with the exception of a re cored radiator and a 180° Stant thermostat and it will NOT go over 193° on the hottest days with the AC on. Karl's car is about the same, I believe.

You need to give us more info so we can try to help you get it right.

It all comes down to proper water flow and air flow.

I read where you have clearanced the pump, but that causes me concern every time I hear it. What is the real configuration of the impeller to the plates over the curve of the two? IMO, that is the single greatest problem area of cause of overheating. Attached is a picture of my water pump showing what I am talking about. Notice how it matches the plate across the curvature of the vanes all the way. It will not have cavitation when it fits as such. It will move water good which you can verify with the cap off and looking down into the radiator. But, if it is close in the middle and wide at the outside because of an impeller that is flat on the top of the vanes, good luck with that!

Many other factors to be sure, but you need to drill down to the real cause first.

Get us some more data so we can try to help you correctly.

Charles

hi charles, tony is my name, thanks for your thoughts, i have had my friend and veteren drag racing buddy working on my car and believe me he is a cut above most car guys, he installed the aluminum edlebrock intake manifold, he blocked off the exhaust crossovers , actually he cut the sections off the manifold to reduce heat under carb to help with overall heat issue, also installed a handmade aluminum spacer under carb too,
he then welded a plate over the impeller inside the water pump, he has seen the design of the fancy superflow water pumps and said this plate will make the water pump more efficent, i not sure of exact design he did, but i believe if he said its correct it would be, i could get details if needed, he owns a 455 66 gto and knows pontiacs extreamly well, he got me to fit a different size pulley wheel to make pump spin faster, he has tuned the car installed electronic ignition and ran vacuum off the manifold , engine has a mild cam, 2.5 inch pypes exhaust, the car goes really good very responsive , my friend is thinking on the next move and i thought i should ask here on the forums to maybe find some ideas....as i am fitting the classic air AC system soon and thats going to make the issue worse

as far as how i read the heat issue, my stock temp gauge works and i also have aftermarket gauges so i read from 2 temp gauges, maybe they are not 100% acurrate, but point is on the street driving around town its 190 and pretty much stays there, but after 5 or more minutes sitting still in heat the car yesterday got to 215 , so thats a 25 degree rise in just a short time, traffic started moving and temp quickly dropped, but if i sat longer im sure it would have kept rising, so i'm not thinking about where i measure heat from, i think point is it rises 25 degree when sitting at idle, thanks

[67GTONUT]

What is the base timing at ? Running vacuum advance?

[fiesta62]

Originally Posted by 67GTONUT

Take a breath.... and go back to basics.

Get us the specs on your car....

Something as simple as Ignition timing can be the cause of your issues.....

hi, i listed a lot of stuff done in my reply to charles , but if you guys want any specfic spec let me know i will ask my mechanic friend, he just rechecked timing and drilled out idle jets to improve the idle adjustment, he checked carb adjustments, as far as he is concerned car is tuned correctly, i can say that it is running much much better now after all his work, it now starts easy, idles smooth, and the auto spins the 275/60 tyres with ease, any info needed let me know please.....

[fiesta62]

Originally Posted by 67GTONUT

What is the base timing at ? Running vacuum advance?

i think from memory base time was 12.....yes my friend was very serious when it came to vaccum advance he said its very important , it runs now off the manifold

[72LuxuryLeMansLa.]

Originally Posted by fiesta62

he then welded a plate over the impeller inside the water pump, he has seen the design of the fancy superflow water pumps and said this plate will make the water pump more efficent, i not sure of exact design he did, but i believe if he said its correct it would be, i could get details if needed, he owns a 455 66 gto and knows pontiacs extreamly well, he got me to fit a different size pulley wheel to make pump spin faster,

I'm not a fan of modifying the cooling system because in correct factory form they work quite well unless you are using a cooling system (radiator, fan etc.) that was designed for a 326ci engine and now have 461ci.... The water pump and divider plate along with the housing (timing cover) were designed to work well together; adding that plate to the impeller is never going to happen on my car because you are changing the design from what engineers spent many hours perfecting.
In my opinion when you make a modification to any system and the results are not satisfactory, you must delete the modification before trying something else or you will never get to the bottom of the problem. So far you have three mods that did not cure your problem. You have an other than stock pulley, a modified water pump, and the wrong amount of system pressurization. Actually you have a fourth because the previous owner installed an aftermarket radiator. I would return all four to stock and try one thing at a time until the problem is found.

Last but not least, usually when a car only gets hot after idle has surpassed a normal amount of time it is because there is not enough air flow through the radiator without the car moving. This is usually the fan, fan clutch, or the fitment of the fan in the shroud.

Karl

[Old Goat 67]

he then welded a plate over the impeller inside the water pump, he has seen the design of the fancy superflow water pumps and said this plate will make the water pump more efficent, i not sure of exact design he did, but i believe if he said its correct it would be, i could get details if needed, he owns a 455 66 gto and knows pontiacs extreamly well, he got me to fit a different size pulley wheel to make pump spin faster,

Tony,
I'm putting my bet on the above modifications. I wouldn't give 2 cents for a flowkooler pump! If the impeller does not fit the cavity correctly, guess what happens? Inefficiency. Then one has to throw money at the rest of the system. So, quite possibly I was wrong about my last statement!
Would need pictures of that pump and plate to even venture a good guess.

The pump is the heart of the system, I'm betting you don't have enough flow through the radiator, but that's me.


Charles

[fiesta62]

Originally Posted by 72LuxuryLeMansLa.

I'm not a fan of modifying the cooling system because in correct factory form they work quite well unless you are using a cooling system (radiator, fan etc.) that was designed for a 326ci engine and now have 461ci.... The water pump and divider plate along with the housing (timing cover) were designed to work well together; adding that plate to the impeller is never going to happen on my car because you are changing the design from what engineers spent many hours perfecting.
In my opinion when you make a modification to any system and the results are not satisfactory, you must delete the modification before trying something else or you will never get to the bottom of the problem. So far you have three mods that did not cure your problem. You have an other than stock pulley, a modified water pump, and the wrong amount of system pressurization. Actually you have a fourth because the previous owner installed an aftermarket radiator. I would return all four to stock and try one thing at a time until the problem is found.

Last but not least, usually when a car only gets hot after idle has surpassed a normal amount of time it is because there is not enough air flow through the radiator without the car moving. This is usually the fan, fan clutch, or the fitment of the fan in the shroud.

Karl

hi, well yes the air moving through rad is the issue at idle so we fitted the fan clutch hoping that was the cause but it seems my old clutch was fine, as new did nothing, but my friend thinks the hayden severe duty is designed to kick in at 190, he feels this might be too late so has read about modifing the spring on the clutch to have it kick in say at 180 etc....this is a trial and error type adjustment so we might just attempt it on the old clutch and see how we go...went for another drive around and 190 bang on no issues as i didnt get stopped for long anywhere today....i understand there are mods but i cant see any advantage reversing them, the pulley size is a common mod this obviously spin pump faster and will cool better, i had the pulley for a non ac car, i just fitted a standard pulley for the ac car, the recored rad must be better is a 4 core rad no reason to go back to stock, these mods dont seem to have helped but i am sure they are not making it worse either...buggered if i know !

[67GTONUT]

Shroud sealed to radiator well?

Fan correct size for shroud?

Fan sitting in correct position within shroud?

Just some more ideas.......

[george kujanski]

Welding a plateto the impeller is ok, but if the clearance from the face of the impeller to the inside surfaceof the pump housing is too large, the coolant recirculates around the impeller rather than get sucked in from the radiator to the cooling passages, and hence there is not enuf coolant flow thru the radiator.

Check that gap and insure it is at a minimum.

George

[fiesta62]

Originally Posted by 67GTONUT

Shroud sealed to radiator well?

Fan correct size for shroud?

Fan sitting in correct position within shroud?

Just some more ideas.......

give me 15 minutes i will post a pic or 2 of fan and shroud

[fiesta62]

fan is 7 blade....appx 17.5 inch tip to tip....blades are about 1 inch off touching the shroud edge, i am assuming this is the correct shroud , pics attached

[fiesta62]

3 more pics of shroud along the bottom of rad, another forum member asked if the shroud is sealed to the base of rad, well in pics you can see its not, same as along the top its not sealed, is this the correct shroud ?