C4 coolant overheated

[tmcorvette]

Last week I went out with my '88 Vette and in few miles the coolant was getting overheated and going out on reservoir cap.

After this I had to fill up coolant reservoir with about 1.5 litres coolant and I've cleared coolant reservoir cap and radiator cap also. Now there isn't any problem with coolant temperature.

What was the problem? Maybe thermostat or waterpump?

Please help me, Thanks.

 

[Robertwav1]

Was the system full to begin with? When was the thermostat changed last? Are the fans or fan working like it's suppose to? More history is needed.

 

[tmcorvette]

Yes, the system was full and the fan was working correctly. I don't know when was the thermostat changed I just bought this Vette few months ago.

 

[Robertwav1]

I would flush the radiator and change the thermostat to start with. It's possible that the radiator is slightly blocked and the water pump forced the coolant out due to back pressure when the stat opened.

 

[tmcorvette]

Thank You very much. I'll try this.

 

[Radar]

The previous Owner may have drained and replaced the coolant and not gotten all of the air out of the block. Then if he did not purge all of the air out of the block, a problem like you described had can happen. With the air bubble in the top of the block passages, the thermostat sensing element would be in air rather than coolant, then when the engine gets super hot, the coolant boils, steam forms and finally opens the thermostat. The coolant then finally can flow to the radiator and some of the air vents out. Hence the problem seems to go away. The trick is to vent that air out before you run the engine.

I would drain, flush, refill, and purge the air. Get a GM shop manual for the Corvette. It shows the proceedures.

Regards,
Bob (Radar)

 

[tmcorvette]

Thanks for your answer, I see and I will do it, but unfortunately there isn't any GM shop in Hungary

Your car is almost the same than my Vette

Thank You,
Tibor

 

[Robertwav1]

Hey tmcorvette,

Let us know how you make out with it....I'm sure someone here will have the answer.

 

[tmcorvette]

OK, Thanks, I will do this on weekend...

 

[wingnut96lt4]

Wow I think you solved my problem. How do you purge the air out of the system?? I added antifreeze to the tank with the pressure cap . Suckced out the tank and refilled it then ran car it overheated and all the water in plastic expantion tank emptyed out Fans work ac and heat . could be AIR or Themostat what do you think ??

 

[Schrade]

Wow I think you solved my problem. How do you purge the air out of the system?? I added antifreeze to the tank with the pressure cap . Suckced out the tank and refilled it then ran car it overheated and all the water in plastic expantion tank emptyed out Fans work ac and heat . could be AIR or Themostat what do you think ??

There might be an air bleed nipple in the line - cannot remember.

Depending on the motor, some systems will push the air through after a few warmed up cycles...

 

[wingnut96lt4]

There might be an air bleed nipple in the line - cannot remember.

Depending on the motor, some systems will push the air through after a few warmed up cycles...

Thanks for that information I removed the intake and found the bleed nipple. On top of the neck of thermostat I will bleed it in the morning Keep you posted

 

[vetteoz]

I will bleed it in the morning

Bleeding A LT1
4th Gen LT1 F-body Tech Articles

 

[wingnut96lt4]

:eyerole Bled the system both hoses hot , heat work BUt I did not see the fan go on. Temp got up tp 240 250 no fa put AC on fans came on temp dropped to 195 200 Could be realy one of THRE which one how do I find it ????:ugh

 

[scout30501]

Same Issue

Last week I went out with my '88 Vette and in few miles the coolant was getting overheated and going out on reservoir cap.

After this I had to fill up coolant reservoir with about 1.5 litres coolant and I've cleared coolant reservoir cap and radiator cap also. Now there isn't any problem with coolant temperature.

What was the problem? Maybe thermostat or waterpump?

Please help me, Thanks.

I am having the same issue here. I have a neighbor who is a mechanic and he said that it is very possible that the thermostat is stuck and not allowing the coolant to pass freely. I am planning to do a flush and fill to see if that will cure the problem. Has the car been sitting for and extended amount of time?

 

[scout30501]

I am having the same issue here. I have a neighbor who is a mechanic and he said that it is very possible that the thermostat is stuck and not allowing the coolant to pass freely. I am planning to do a flush and fill to see if that will cure the problem. Has the car been sitting for and extended amount of time? The reason I am asking is that the previous owner had let the car sit for around 14 months outside and that has caused multiple issues.

 

[catbert]

The first culprit to check for overheating is the thermostat. They stick open they stick closed and they stick partly open. I'd replace it or check the operation in a pot on the stove.

 

[forrest]

The first culprit to check for overheating is the thermostat. They stick open they stick closed and they stick partly open. I'd replace it or check the operation in a pot on the stove.

one thing has not been mentioned all C-4s are vacuum cleaners for the road. take a look under the front bumper and make sure that the radiator is clear of road debris also from inside look from right side of car and look thru were the A/C is mounted in front there is a opening you can see between A/C and radiator. once you know radiator is clear fill the radiator let sit awhile start car let it warm up turn on A/C to get cooling fan to turn, or you can jump A to B to do same raise up idle to around 1500 RPM top off and cap. if your anti freeze is in a proper protection mixture you should not have any problems. if it reoccurs start looking deeper. like thermostat and so on.