Riddle me this C2 Cooling Problem

[Steve L.]

Re: Riddle me this C2 Cooling Problem

Clutch is a factory correct and I see not evidence of a tab or setting. Timing is correct to the book,vacuum is not a problem and advance curve is good. Radiator has been cleaned, flushed, flow tested, water wetter added.

Once the car overheated on the Power tour we gave it a very thorough once over, We really left no stone we know of un-turned. Still after our test drives, she is overheating.

[Steve L.]

Re: Riddle me this C2 Cooling Problem

Clutch is a factory correct and I see not evidence of a tab or setting. Timing is correct to the book,vacuum is not a problem and advance curve is good. Radiator has been cleaned, flushed, flow tested, water wetter added.

Once the car overheated on the Power tour we gave it a very thorough once over, We really left no stone we know of un-turned. Still after our test drives, she is overheating.

[Donald T.]

Re: Riddle me this C2 Cooling Problem

Any thoughts on reducing the amount of antifreeze to 75/25 or so? I don't know if it is true or not but I read somewhere that antifreeze does not dissipate heat as well as plain ol' water. The term coolant is really a misnomer; it's just antifreeze. If you drive your car during the winter you may have to adjust the mix back to 50/50, but it certainly wouldn't hurt to reduce antifreeze in the summer. Just a thought; don't know if it will help any.

[Donald T.]

Re: Riddle me this C2 Cooling Problem

Any thoughts on reducing the amount of antifreeze to 75/25 or so? I don't know if it is true or not but I read somewhere that antifreeze does not dissipate heat as well as plain ol' water. The term coolant is really a misnomer; it's just antifreeze. If you drive your car during the winter you may have to adjust the mix back to 50/50, but it certainly wouldn't hurt to reduce antifreeze in the summer. Just a thought; don't know if it will help any.

[Steve L.]

Re: Riddle me this C2 Cooling Problem

Thermostat is the second one in the car. Both thermostat acted the same with the same operting tempertatures. The current thermostat is a fail safe model. 180 degree.

[Steve L.]

Re: Riddle me this C2 Cooling Problem

Thermostat is the second one in the car. Both thermostat acted the same with the same operting tempertatures. The current thermostat is a fail safe model. 180 degree.

[Mike Cobine]

Re: Riddle me this C2 Cooling Problem

Well, antifreeze isn't just antifreeze, it is anti-boil to a point. If you ran an old car back then on plain water, and tried to run the air, it would boil over. Go to a 50/50 mix and the air could run without the car overheating.

However, the mix must be right. If you get more antifreeze than water (60/40, 75/25, etc.), you can expect it to overheat. If you changed the radiator and didn't flush the block out, including the block drain plugs, you could have too much antifreeze in there. Usually not a problem but Corvettes are on the edge anyway.

You could have also managed to get junk in the bottom tubes of the radiator, if you flushed the block through the radiator and not through the drain plugs. Block one tube with scale or rust and you lost a lot of cooling capacity.

But a antifreeze mix of AF 25/75 water should be enough to prevent boiling over and freezing.

The problem still sounds like one where you are marginal on capacity. In the high heat load of city traffic (slow air movement, maximum heat soak of area), you can't shed enough heat and it goes to 210-220.

On the highway, with little heat soak of the area around the car and greater air flow, you are fine at 180.

Now the reason is probably what has changed: water pump, tune-up settings, radiator, and coolant.

If you went to a larger fan and used the same fan clutch, then it needs readjusting as the greater mass of a larger fan will not spin as fast and will actually pull less air as a result.

You also haven't mentioned if you were running the air. Or if you have had it recharged between last year and this year.

[Mike Cobine]

Re: Riddle me this C2 Cooling Problem

Well, antifreeze isn't just antifreeze, it is anti-boil to a point. If you ran an old car back then on plain water, and tried to run the air, it would boil over. Go to a 50/50 mix and the air could run without the car overheating.

However, the mix must be right. If you get more antifreeze than water (60/40, 75/25, etc.), you can expect it to overheat. If you changed the radiator and didn't flush the block out, including the block drain plugs, you could have too much antifreeze in there. Usually not a problem but Corvettes are on the edge anyway.

You could have also managed to get junk in the bottom tubes of the radiator, if you flushed the block through the radiator and not through the drain plugs. Block one tube with scale or rust and you lost a lot of cooling capacity.

But a antifreeze mix of AF 25/75 water should be enough to prevent boiling over and freezing.

The problem still sounds like one where you are marginal on capacity. In the high heat load of city traffic (slow air movement, maximum heat soak of area), you can't shed enough heat and it goes to 210-220.

On the highway, with little heat soak of the area around the car and greater air flow, you are fine at 180.

Now the reason is probably what has changed: water pump, tune-up settings, radiator, and coolant.

If you went to a larger fan and used the same fan clutch, then it needs readjusting as the greater mass of a larger fan will not spin as fast and will actually pull less air as a result.

You also haven't mentioned if you were running the air. Or if you have had it recharged between last year and this year.

[Gary C.]

Re: Riddle me this C2 Cooling Problem

Steve

Clarify 4 core aluminum radiator. If it is some type of replacement, I would call Tom DeWitt for an explanation of the heat dissipating capacities of the the original Harrison type versus what you have installed. Might be telling.

[Gary C.]

Re: Riddle me this C2 Cooling Problem

Steve

Clarify 4 core aluminum radiator. If it is some type of replacement, I would call Tom DeWitt for an explanation of the heat dissipating capacities of the the original Harrison type versus what you have installed. Might be telling.

[terry leeker]

Re: Riddle me this C2 Cooling Problem

Does the lower radiator hose have an internal spring. I have seen the suction hose collapse (usually at speed and not traffic thought) when omitted. FYI, a 50/50 ethanol glychol mixture has about 10% less heat conductivity property than pure water. In a pinch, pure water with Reline in it will mask some cooling problems but pursuing as you are the real culprit is the right way to go.

[terry leeker]

Re: Riddle me this C2 Cooling Problem

Does the lower radiator hose have an internal spring. I have seen the suction hose collapse (usually at speed and not traffic thought) when omitted. FYI, a 50/50 ethanol glychol mixture has about 10% less heat conductivity property than pure water. In a pinch, pure water with Reline in it will mask some cooling problems but pursuing as you are the real culprit is the right way to go.

[Steve L.]

Re: Riddle me this C2 Cooling Problem

Radiator was flushed seperate from the Block. anitfreeze levels 50/50 or 25/75 have made no difference. Fan and fan clutch are stock.

A/C is always on. The Power tour was from Dallas Tx to Green Bay.

[Steve L.]

Re: Riddle me this C2 Cooling Problem

Radiator was flushed seperate from the Block. anitfreeze levels 50/50 or 25/75 have made no difference. Fan and fan clutch are stock.

A/C is always on. The Power tour was from Dallas Tx to Green Bay.

[Thomas D.]

Re: Riddle me this C2 Cooling Problem

I guess the old guys are on vacation or just too tired of answering cooling questions, so I'll jump in here. Steve, you stated new "aluminum four core". I'm going to guess that you went with an aftermarket brass/copper radiator. Later you said you it tested out, flushed out, flow tested, etc. This sounds like an old radiator. You need to explain exactly what type (material) and brand (company) the existing radiator is before anyone can (should) make recommendations.
We all grew up hearing the term "four core" and since we didn't know anything about radiators, everyone keeps using the term. A "core" is the center section of the radiator that includes the "tubes" and fin and side channels. This is what you buy when a radiator shop "re-cores" a brass/copper radiator.
The passage ways in the core are refered to as "tubes" or "rows". So if you have a copper radiator, the correct term is a four row. It's pretty easy to spot a replacement c/b radiator because it consists of a "core" and tanks on each end. Whereas the stock aluminum radiator has no end tanks, and the part number 3155316 is clearly stamped on the top. This radiator did not use "tubes" as it was made by stacking plates. The plates formed a passage way 3" wide and that's why the stock radiator works so well.
You could purchase an aftermarket aluminum radiator built like the c/b design but no one makes more than a two row. These typically use two 1" tubes and even this design is a downgrade from the original specs.
See the picture below. Is this what you have? If not, that's probably the problem.