[GoreMaker]

Planning to install a new radiator in my '77 Trans Am W72 400 4-speed. The old setup was fine, temperature barely ever reached 180f under any circumstances. I'm planning to stick to mostly the same setup (re-using the old Delco thermostatic fan clutch, stock fan, stock shroud sealed all around). I'm installing a new Flowkooler aluminum water pump as preventive maintenance since I'm replacing the front timing cover anyways. New thermostat (preventive maintenance) and housing (old one is pitted and worn) onto "new" (to me) Performer aluminum intake manifold. The only reason I'm replacing the radiator is because the current one is 45 years old and looks a little worse for wear.

So... Cold Case aluminum or US Radiator High Efficiency copper/brass 4-core? I'm not considering anything else. It's either modern aluminum or modern copper/brass. None of this fancy tri-flow stuff. Not looking for recommendations on changing my setup. I'm sticking with what I know works.

[76TA462]

Manny years ago I swapped out my original copper rad in my 76 TA for a Griffin aluminum 2 row 1.5 inch due to cooling issues. Problem solved. Recently installed a 2 row 1 inch Cold Case and all good. Swapped to Cold Case because I went electric fans and it was easier to buy the ran, shroud, fan package than fabricating. Recouped some costs by selling the Griffin. While using the Griffin I used a clutch fan, seven blade, and my OEM shroud.

[77 Canamman]

The Flowkooler is not a wise or necessary improvement. Search the forums here. Plenty of guys have solved their cooling woes simply by ditching the overly-effective Flowkooler and installing a stock type water pump as long as it has the cast impeller and the plate clearance is within spec. The Flowkooler simply moves the coolant too quickly to properly absorb heat from the castings. There is an aluminum stock replacement pump on the market with a cast impeller if weight savings is your goal.

[OCMDGTO]

Using Cold Case here

[TAKerry]

I bought a cold case for my 79, 4 speed. Have yet to install. Hope it works well.

[Sirrotica]

FWIW, you can not push water through a cooling system too fast that it won't transfer heat. If the Flow Kooler makes the engine heat up, it's not for that reason. Quote below is from "9 cooling system myths".

1. The idea that removing the thermostat causes the coolant to move so fast that the heat can’t be dissipated because the water isn’t in the radiator long enough?

One only needs to look at the engine side to expose this nonsense, if the water is going too fast for heat transfer, it’s not going to be able to extract any heat from the engine either with the result the water would stay cool and the engine heating up into a red hot block……..Doesn’t happen!

The faster the water moves through the system, the more heat can be transferred, that’s what the thermostat does, controls the rate of coolant flow. It does get to a point when no further increase in flow will create any further cooling rather than faster flow impeding cooling.

On all Pontiacs, the factory increased the water pump speed on all of their "Heavy Duty" cooling applications" If increased water pump speed decreased cooling this would not have worked. It does work, so the water cannot travel too fast to absorb, or release heat. Flow Kooler deviated from the factory impeller design, and I believe that their design is less efficient in the Pontiac application, not too efficient. Hence switching back to a factory style impeller provides better efficiency over the Flow Kooler.

One other thing that can impede cooling directly related to the water pump is too little pressure in the top of the engine. This allows steam pockets to form. Steam will absolutely will not allow the coolant to absorb heat, because the gases insulate the top pockets in the cooling system, causing even more steam to form, leading to overheating. It starts a vicious cycle that multiplies.

This phenomenon is what also causes a meltdown in a nuclear reactor, steam forms to the point there is little heat transfer, and the reactor core is no longer covered by water, it's covered by steam. The reason that the domes are plumbed to be able to vent steam in an emergency.

Pressure, and flow are two things that aid in heat transfer. As soon as gasses form in the system, is when the overheat cycle starts. Some of the later automotive designs have provisions to vent steam out of the block and heads where it forms, to head off the formation of steam.

Removing a thermostat lowers the pressure in a cooling system, further multiplying the overheating problem. When a restrictor is put in place in a automotive cooling system, in place of a thermostat, and the car will run cooler, it is assumed that the water was moving so fast that it doesn't absorb heat, or radiate it. The fact is, the restrictor raises the pressure in the block, removing the steam pockets. and the system cools more efficiently. That is how that myth is interpreted, but pressure increase in the block is never considered as a factor that eliminated the overheat problem.

Pontiac engineers probably made the most efficient design impeller many years ago. Same engineers that in the 55-59 models used reverse cooling to cool the Stratosteak engine. it was a more efficient system, but it cost more to make, and there was corrosion problems with the gusher system made of sheet metal in the cylinder heads. Pontiac then switched over to the same conventional system that other engines had been using. In the 90s Chevy brought back the reverse cooling system, A system that Pontiac engineers had used 40 years previously, as all new....LOL

I owned a reverse cooled LT1 in a 97 T/A for a while, the system worked fine while I owned it. It suffered a fuel leak and had a minor engine fire at 150,000 miles, and I sold it. Never any cooling problems with it.

GM made another engine that was subject to overheating, the 6.5 turbo diesel. In the mid 90s the reconfigured the cooling system to use a high output water pump (said to pump 40% more water through the engine) a 2 thermostat water crossover to handle the extra flow, and a fan clutch that was engaged longer, plus a redesigned 7 blade fan to move more air. These changes did stop the OH problem, further proving that coolant speed, or volume, will not inhibit engine cooling, it makes the cooling system more efficient.

[GoreMaker]

Yeah I wasn't gonna argue with the "too much flow" thing. That pretty much goes against any rules of thermodynamics, but I hear it all the time and there's no point trying to correct it. There's something to be said for the flow being fast enough to potentially bypass some passages, thereby leading to hot spots that lead to steam pockets, but I don't see that being an issue with a mechanical water pump running at stock speed no matter how efficient it is. Hadn't considered that the Flowkooler impeller design might be less efficient. I also have a new cast impeller water pump here, might be fund to try back-to-back comparisons with the Flowkooler to see which one does best. Though that sounds messy...

The water pump I was running before had a crappy stamped steel impeller, and the divider plate had at least 1/4" gap. I had zero engine cooling issues with that setup, so I'm not too concerned with this new setup. I've set the divider plate 0.030" from the impeller on the Flowkooler, which is basically the thickness of the gasket.

[Sirrotica]

Originally Posted by GoreMaker

Yeah I wasn't gonna argue with the "too much flow" thing. That pretty much goes against any rules of thermodynamics, but I hear it all the time and there's no point trying to correct it. There's something to be said for the flow being fast enough to potentially bypass some passages, thereby leading to hot spots that lead to steam pockets, but I don't see that being an issue with a mechanical water pump running at stock speed no matter how efficient it is. Hadn't considered that the Flowkooler impeller design might be less efficient. I also have a new cast impeller water pump here, might be fund to try back-to-back comparisons with the Flowkooler to see which one does best. Though that sounds messy...

The water pump I was running before had a crappy stamped steel impeller, and the divider plate had at least 1/4" gap. I had zero engine cooling issues with that setup, so I'm not too concerned with this new setup. I've set the divider plate 0.030" from the impeller on the Flowkooler, which is basically the thickness of the gasket.

You're correct, some people don't factor in pressure in a closed cooling system also entering into the equation, but pressure to minimize steam pockets is very important. Having wrestled with cooling Pontiacs on an oval track, you get to factor in everything, not just theorists repeating the too fast to cool idea.

Heat travels from one unequal object to another at the speed of electricity, watts enter into the formulation of heat transfer. Coolant will never surpass the speed of electricity. As I've already listed, GM/Pontiac engineers did speed up coolant flow, and pressure, to aid in efficiency.

[GoreMaker]

hah! If you want to roll your eyes until they fall back into your head, read this "helpful article" on this extended warranty site that's CHOCK FULL of complete misinformation and potentially damaging advice: https://blog.protectmycar.com/can-yo...engine-coolant

It's the second search result in Google when looking up "best water for antifreeze". It's freaking terrifying that information like this exists and gets pushed to people who don't know any better. The internet certainly didn't do us any favors as far as debunking myths...

[nUcLeArEnVoY]

My 79' has trouble reaching operating temp after I went through the cooling system recently. Right now I'm running a Flowkooler 11-bolt unit clearanced to .045" with gasket, Cold Case radiator, stock shroud sealed all around with weatherstrip, heavy duty fan clutch on stock 7 blader, and 160-degree balanced sleeve stat. I've never seen my gauge needle pass the first tick even in SoFlo 85 degree weather after these changes, so I may need to put in a 180, but then summer is coming up so I'm on the fence about it. I can straight up grip and hold my hand on the radiator hose after 30 mins of running and not get burnt/injured. All I can tell you is that Flowkoolers and CC radiators cool really well and are best used with stock shroud and fans.

[GoreMaker]

Ended up going with a Cold Case aluminum radiator.

Fun fact;

- OEM brass/copper 4-core radiator: 26.8 pounds
- Cold Case aluminum radiator: 15.5 pounds

(both completely dry, both for manual trans, both with radiator cap on and nothing else)

[Elarson]

Originally Posted by Sirrotica

FWIW, you can not push water through a cooling system too fast that it won't transfer heat. If the Flow Kooler makes the engine heat up, it's not for that reason. Quote below is from "9 cooling system myths".



On all Pontiacs, the factory increased the water pump speed on all of their "Heavy Duty" cooling applications" If increased water pump speed decreased cooling this would not have worked. It does work, so the water cannot travel too fast to absorb, or release heat. Flow Kooler deviated from the factory impeller design, and I believe that their design is less efficient in the Pontiac application, not too efficient. Hence switching back to a factory style impeller provides better efficiency over the Flow Kooler.

One other thing that can impede cooling directly related to the water pump is too little pressure in the top of the engine. This allows steam pockets to form. Steam will absolutely will not allow the coolant to absorb heat, because the gases insulate the top pockets in the cooling system, causing even more steam to form, leading to overheating. It starts a vicious cycle that multiplies.

This phenomenon is what also causes a meltdown in a nuclear reactor, steam forms to the point there is little heat transfer, and the reactor core is no longer covered by water, it's covered by steam. The reason that the domes are plumbed to be able to vent steam in an emergency.

Pressure, and flow are two things that aid in heat transfer. As soon as gasses form in the system, is when the overheat cycle starts. Some of the later automotive designs have provisions to vent steam out of the block and heads where it forms, to head off the formation of steam.

Removing a thermostat lowers the pressure in a cooling system, further multiplying the overheating problem. When a restrictor is put in place in a automotive cooling system, in place of a thermostat, and the car will run cooler, it is assumed that the water was moving so fast that it doesn't absorb heat, or radiate it. The fact is, the restrictor raises the pressure in the block, removing the steam pockets. and the system cools more efficiently. That is how that myth is interpreted, but pressure increase in the block is never considered as a factor that eliminated the overheat problem.


GM made another engine that was subject to overheating, the 6.5 turbo diesel. In the mid 90s the reconfigured the cooling system to use a high output water pump (said to pump 40% more water through the engine) a 2 thermostat water crossover to handle the extra flow, and a fan clutch that was engaged longer, plus a redesigned 7 blade fan to move more air. These changes did stop the OH problem, further proving that coolant speed, or volume, will not inhibit engine cooling, it makes the cooling system more efficient.

1000% correct in every detail.

Eric