Cooling problems with 72 350, 4 speed

[Tony L.]

Need some information: I recently installed Vintage Air in my survivor 72 convertible. I am original owner with 16k miles. Installed Vintage Air due to move to Florida. Installed a new radiator matching the original ( 350 4 speed convertible ) radiator and installed high flow water pump. It seems that any stopping ( traffic lights etc. ) for anytime over a few minutes causes the temp to soar. Car must be in motion. Car did not have A/C originally. Do I need a larger radiator, electric fans etc. Any advise is welcome. Thanks TL

[Alan S.]

Re: Cooling problems with 72 350, 4 speed

Hi Tony,
First an easy one to check…
All the various seals around the radiator to core support, the core support to hood, and core support to front valance, are really vital to engine cooling since they ensure that the fan pulls the air THROUGH the core rather than AROUND it.
Have you checked to make sure they're ALL in place?
Regards,
Alan

[Joe L.]

Re: Cooling problems with 72 350, 4 speed

Need some information: I recently installed Vintage Air in my survivor 72 convertible. I am original owner with 16k miles. Installed Vintage Air due to move to Florida. Installed a new radiator matching the original ( 350 4 speed convertible ) radiator and installed high flow water pump. It seems that any stopping ( traffic lights etc. ) for anytime over a few minutes causes the temp to soar. Car must be in motion. Car did not have A/C originally. Do I need a larger radiator, electric fans etc. Any advise is welcome. Thanks TL

Tony------

If your car is a base engine with 4 speed and without original A/C, it should have had a Harrison aluminum radiator of GM #3155316. Is that the radiator that you replaced with a reproduction of the original (i.e. DeWitts)? This radiator used a circular, sheet metal fan shroud.

1972 with A/C did not originally use this radiator. Rather, that application used a copper/brass radiator. However, the cooling capacity of that radiator and the 3155316 are about the same. Nevertheless, with A/C I'd probably want to use the original type copper/brass radiator and the reinforced plastic fan shroud.

[Edward J.]

Re: Cooling problems with 72 350, 4 speed

Tony, Not sure how many blades your fan is, but my 72 has a/c and has a 7 blade fan to move more air, and as Alan says check the seals around the shroud .you'll want to pull as much air in front of the shroud through the radiator as possible. How is the clutch fan. when the temp on gauge is showing a rise you should feel air being pulled through the shroud at about 1500 RPMS.

[Tony L.]

Re: Cooling problems with 72 350, 4 speed

The shroud is tight. I replaced the fan clutch with a direct drive unit to keep it spinning full time. Do you kow if the AC cars had a larger capacity radiator? I will check the number of blades. THe heat rises so fast soon as the car stops. Anyone know of electric fans for the 72?

[Joe L.]

Re: Cooling problems with 72 350, 4 speed

The shroud is tight. I replaced the fan clutch with a direct drive unit to keep it spinning full time. Do you kow if the AC cars had a larger capacity radiator? I will check the number of blades. THe heat rises so fast soon as the car stops. Anyone know of electric fans for the 72?

Tony------


Which radiator do you have in the car now?

[Tony L.]

Re: Cooling problems with 72 350, 4 speed

I did replace with a reporduction of the origial. DeWitts. Mine uses the circular metal fan shroud. I will investigate that copper/brass radiator and the plastic fan shroud. Question, do you know if I can switch to that radiator and keep the metal shroud?

[Michael W.]

Re: Cooling problems with 72 350, 4 speed

If a full time direct drive mechanical fan won't cool it, neither will an electric.

I'd swap the pump for an OEM unit. No need for a high flow unit.

[Tony L.]

Re: Cooling problems with 72 350, 4 speed

The DeWitt replacement

[Joe L.]

Re: Cooling problems with 72 350, 4 speed

I did replace with a reporduction of the origial. DeWitts. Mine uses the circular metal fan shroud. I will investigate that copper/brass radiator and the plastic fan shroud. Question, do you know if I can switch to that radiator and keep the metal shroud?

Tony------


Unfortunately, the metal shroud is quite inefficient. However, you cannot use the plastic shroud with the original or reproduction of the 3155316 radiator.

Cooling-wise, the 3155316 has about the same capacity as the copper/brass radiator used with small blocks with A/C and/or THM transmission. I think the big cooling difference between the two has to do with the efficiency of the shroud.

The 3155316 aluminum radiator was never used for a 1969-72 Corvette with A/C. However, it was used for all C2 small block with A/C. So, this strongly implies that the radiator, itself, has sufficient cooling capacity for an A/C application.

[Michael G.]

Re: Cooling problems with 72 350, 4 speed

Curious, have you pulled and discarded the thermostat in an effort to solve the problem. This could actually be a cause.

[Joe R.]

Re: Cooling problems with 72 350, 4 speed

Tony,

Your Corvette will never cool properly unless you change the radiator to an aluminum high capacity radiator with two electric fans. DeWitt's sells such a combination along with other suppliers. The package has the high capacity radiator, shroud and two electric fans with thermostat controls. This is the only way to cool your Corvette.

JR

[Daniel K.]

Re: Cooling problems with 72 350, 4 speed

Hi Tony. Just curious what other modifications/updates/replacements you've made to your car over the years. The fact that you're the sole owner of this 16,000 mile car seems a significant factor in this thread. Would you consider solving all this by pulling the vintage air, dropping the top and going a little heavier on the accelerator pedal?

[Edward J.]

Re: Cooling problems with 72 350, 4 speed

Tony, not sure but you really have not said anything about the temp. how high is it going on the gauge? and do you have access to a Infrared gun to check the engines temp. at the thermostat housing and upper and lower hoses areas at radiator. this should give you and idea just how the radiator and fan are doing there job. and the thermostat operation.

[Gene M.]

Re: Cooling problems with 72 350, 4 speed

Tony,
I can share what I did with my 65 327 & 5 speed w/Vintage air. Brand new hi performance radiator from Dewitt, 160 thermostat, 7 blade BB fan blade from a Pontiac, centrifugal fan clutch that stays locks up at lower temperatures. Also extended the metal fan shroud so the fan blade is about 60 - 75% inside the shroud. The shroud is sealed good to the radiator surface. The front of the radiator has a piece of fiberglass screen so I can fling off the bugs and they don't get imbedded in the core. Handles heat well except the 107 degrees we had on the road tour. But that is not normal for us in northeast. We don't have any extra electric fans as of yet do not see the need.