CCA Corvette Parts

The low speed cooling fan comes on when the coolant temperature reaches 226°. It goes off if the coolant temperature goes below 219°. The high speed cooling fan comes on when the coolant temperature reaches 235°. It is turned off if the coolant temperature goes below 226. If the A/C is on and the coolant temperature reaches 185° the low speed cooling fan is turned on when the car is going 35 MPH or less.

I think you have a blockage in your cooling system...

Peace
Chip

TEXHAWK0

The sensor in the tank is only a level sensor. I don't think it has anything to do with temperature sensing and the control of the fans. Those temperature sensors are usually on the engine block.

ptindall

I agree with everything you wrote except your conclusion. I understand that it is variable, but not much. Boil one on your stove. Closed to wide open happens in a very short window. And you still have one major flaw. Let's say you are correct and a stuck open causes your car to reach 230 degrees. Now will you agree that the thermostat is always wide open? But in an otherwise healthy cooling system, hitting 230 does not mean you are on a runnaway train to 260, does it? And think about the system as a whole. All the system has to do is pull more heat of out the radiator than the engine is generating, correct? The radiator will radiate the most heat (airflow constant) when the coolant inside is hotter because there will be the biggest temp difference between inside and outside of the radiator. This "hotter and hotter" idea about a stuck open thermostat makes no sense because when an engine is aleady slightly above it's normal operating range, the thermostat is supposed to be wide open anyway. It might cause the engine to run slightly hotter than normal, but not a runnaway train effect to the piont of boiling the coolant and causing a head to warp like the post that started this debate. You pionted out that a healthy cooling system has lots more cooling power than the engine generates under normal driving conditions. When the thermostat is wide open and the coolant is nice and hot, that's when the cooling system is working to capacity, and therefor removing more heat than is being generated, not less.

97C5driver

Well today I replaced the resovoir, replaced the thermostat/housing, and flushed my coolant system and installed fresh dex cool/distilled water.

First- how many gallons of liquid(dex-cool/water) does the C5 hold?
I put two gallons of dex-cool and 1.5 gallons of water and its overfilled!

Ok so when I removed the old resovoir i discovered the stem (north of the cap, where the hose connects) had a hairline crack in it!
Could this have cause any of my probs.? Im thinking partly.

So tomorrow I will fix the coolant level and take her for a test drive and pray that there are no problems.

DeeGee

I'd say a hairline crack would do it

I've seen quite a bubbling of coolant when I took the cap of a pressurised cooling system once. I only made that mistake once:o

OSCS Ret

12.1 Quarts I believe, or just a hair over 3 gallons...

VRROOOM2

Only once??? WOW!! Fast learner... Me?

ptindall

I bet your problems were the cap and that crack. I bet you'll be fine now. Good luck!

TEXHAWK0

Just a lucky guess!!

Also, one of my previous notes points out that you will likely only be able to drain about 2 gallons (of the 3 gallon system capacity), out of the system, so you should only need 1 gallon of Dexcool and 1 gallon of distilled water.
See post #25.

97C5driver

actually i got all 3 gallons out the two times i flushed it and the original draining!

still havent had a chance to test drive it! will do so today and post ...

thanks to everyone for the help. It has been of great help.

froggy47

Thanks for correcting that nutty post.

gpracer1

Try reading post# 40 and tell me if that makes sense.

ptindall

I'm not at war with you gpracer1, but I enjoy a good debate and I think I'm right here. You did not respond to my post #43, and I was hoping you would. Please try to explian the following senario. You have a perfectly functioning factory original car and cooling system. You go towing a trailer up a long hill on a hot day and get your coolant temp up to 230. Possible, correct? At this time, a functioning thermostat will never partially close, correct? Now your trailer breaks off and you hit level ground. Now the cooling system is pulling more heat out of the radiator than the engine is generating and the coolant temp will fall back down to the piont where the thermostat will partially close, correct? So during this time where the temp is dropping, the thermostat is wide open and the temp is falling. How is that different than if the thermostat was stuck open? According to your theory, the temp will continue to spiral up.
You have expained the correct functioning of a cooling system, but you have not explained how a functioning thermostat can recover from running hot while a stuck open thermostat will cause runaway overheating to the piont of boiling and head warpage.

97C5driver

well to lighten the mood, i ran my car for about 25 minutes and no problems!

Tomorrow I will drive around town and see what happens.

gpracer1

No war here, I have just been working on cars for
20 years and I know the operation of the cooling system more than the average garage queen owner
If I read your post correctly, your trailer falls off when running hotter than normal........thermo is open wide because you have exceeded the ability of the radiator and airflow amount, to cool the engine. ( ie, pulling trailer, slow speed air, WOT, high rpm.) Now the trailer falls off, you have less load, heat and more speed (air flow) the radiator can now handle the heat with less load and more air flow and cools the system. "So during this time where the temp is dropping, the thermostat is wide open and the temp is falling. How is that different than if the thermostat was stuck open? According to your theory, the temp will continue to spiral up." <----only if load exceeds capacity. (Lower heat load now, lower rpms as in lower flow of coolant through radiator and higher airflow speed.
Since the system is now able to cool due to the load rating not being exceeded, the thermo will reduce size according to the load which is lighter.
All is good, I love a good civil debate

froggy47

"Some cars overheat, some cars overcool with a stuck thermo. Depends on driving conditions, airflow and cooling system capacity."

Good post, but, I think maybe theoretically, a car could circulate water "too fast" to cool with a stuck open stat, but for practical purposes, in the real world, I don't believe it would happen.

Stuck open, to me, it's like a safety thing, so as not to overheat.

Aren't stats designed so that if/when they fail, they fail open, not closed?

gpracer1

Well if your last sentence were true, then most people with overheating problems due to stuck thermostats have stuck wide open thermostats.
But on a real note, they stick closed, partially open and wide open. Just depends on how much friction or corrosion there is on the metal parts, or if the wax pellet inside is bad.

ptindall

The thermostat will not reduce size according to load. It does not know load. It works purely on coolant temp. It will reduce size only when the coolant temp drops to the piont where it starts to close. That will happen as a result of reduced load, but it is not the thermostat reducing size that causes the reduction in temp. See my piont? Do you agree that it is wide open while the temp is dropping down to the piont that it starts to reduce in size? While that is happening, the system is functioning exactly the same as if it were stuck open.
In the real world, there may be a lot of reasons people could come to the conclusion that a stuck open thermostat has indeed caused overheating, but that does not mean that's exactly what happened. I have agreed that it is possible that a stuck open may cause a car to run a little hotter than normal. Maybe a customer freaked out when they saw this and had the car towed in. You find the thermostat and it functions perfectly afterward. In the real world, if the thermostat is stuck open, there is a high probability that the rest of the system is not in tip top shape. Maybe in changing a thermostat you shifted just enouph sludge or debris somewhere else to improve the systems cooling capacity. Who knows?
I have not been a mechanic for 20 years. But I'm no nooB either. I was a customer at Robert's Performance Garage when I was layed off from Bombardeir. Based on what he knew of my automotive knowledge, Robot offered me a job upon hearing I had lost mine. I worked there for a year and got nothing but priase, but getting dirty pulling trannies on 4X4 Chevy trucks from the '80's in the desert heat was not something I wanted to do for a lifetime. So I became a machinist. I turn down work from friends, but do all the work on all my family's cars.

gpracer1

All I can say is that the thermostat is constantly opening and closing partially. Yes it is purely controlled by the coolant temp, but coolant temp is controlled by radiator efficiency, airflow, BTU's of heat produced by the motor, and coolant flow (thermo opening size and rpms.)
Its all related to each other, thats why its more complicated than just putting it in a glass of hot water and seeing what happens.

Looks like we covered this one pretty good

fr0stb1t3

I'm a computer nerd trying to become a car nut

And I will agree that at least on a computer, you can have too much flow in a closed water cooling based system. I had a pump to large in my computer at one time and it was moving so fast that my radiator didn't have time to cool it. It is a run away affect so it seems to get exponentially hotter as it goes on.


Now how well that apply's to cars I'm not sure. Just my experience with water systems :P