Help! Overheated

[wingnut96lt4]

:eyeroleHello guys Last night my vette overheated and boiled all the coolant out of the overflow tank. The other tank{pressure cap} is full. Could fan not be going on?? Thermostat stuck?? Or other. Any help would be great . Thanks

 

[Hib Halverson]

Something is a little funky here...

Are you saying the car overheated at night when it's cool out?

How did you determine the car overheated, actual observation or an assumption after you noted the overflow bottle was empty?

If the engine truly boils over, ie: the cap pressure relief vents, the overflow bottle will contain coolant, but the high-fill bottle (the one the pressure cap is on) might be low. During the overheating incident, did you observe that happening?

After an incident like that, the pressure decrease in the closed system will suck air in from an empty overflow bottle and lower the coolant level.

In any event, you want to check for:


1) excessively low coolant level combined with low coolant level sensor failure
2) cooling fan(s) failure
3) faulty thermostat
4) blown head gasket

The FSM explains how to test for bad head gaskets and how to test the cooling fans.

 

[Tuna]

^
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What he said plus checking for trash blocking the radiator.

 

[wingnut96lt4]

The temp gauge was up around 260 water coming out of a bubling overflow tank Today I checked and fans are both working ac blows cold heat is fine coolant was up. Both top and bottom hoses were soft like not much water folwing. I think the thermostat is a good place to start. Should I be carefull about getting water on opti>??? Not like I will pour it on but may drip???? Thanks

 

[Hib Halverson]

The temp gauge was up around 260 water coming out of a bubling overflow tank Today I checked and fans are both working ac blows cold heat is fine coolant was up. Both top and bottom hoses were soft like not much water folwing. I think the thermostat is a good place to start. Should I be carefull about getting water on opti>??? Not like I will pour it on but may drip???? Thanks

Clearly, you boiled it.

I agree. Check the 'stat.

On the fans, you have to make sure they're working on high and low. The only way to fully test the system is using the diagnostic instructions in the FSM.

If you haven't changed coolant in the last 3 years, now's a great time to do it.

Get the top off the cooling stack and inspect the space in front of the HVAC for debris and also look between the HVAC and the radiator for debris. It's not uncommon to have plastic bags get sucked up by cooling airflow then get stuck on the HVAC condenser or lodge between the HVAC and the radiator.

 

[birdman11]

Clearly, you boiled it.

I agree. Check the 'stat.

On the fans, you have to make sure they're working on high and low. The only way to fully test the system is using the diagnostic instructions in the FSM.

If you haven't changed coolant in the last 3 years, now's a great time to do it.

Get the top off the cooling stack and inspect the space in front of the HVAC for debris and also look between the HVAC and the radiator for debris. It's not uncommon to have plastic bags get sucked up by cooling airflow then get stuck on the HVAC condenser or lodge between the HVAC and the radiator.

I would also look into ditching the stock thermostat for a much cooler one. Especially in the summertime. A custom chip is needed with the corrected fan on/off temps programmed in. Then you should be all set.

 

[roger longman]

It is NOT a good idea to install a 'cooler' thermostat. ie. one that opens at a lower temperature. The only effect that would have would be to increase the amount of time that the engine runs before getting to running temperature, resulting in increased wear. As long as it is functioning correctly, the stock thermostat is the right one. Also setting the fans to come on earlier is a bad idea.......Roger.

 

[birdman11]

It is NOT a good idea to install a 'cooler' thermostat. ie. one that opens at a lower temperature. The only effect that would have would be to increase the amount of time that the engine runs before getting to running temperature, resulting in increased wear. As long as it is functioning correctly, the stock thermostat is the right one. Also setting the fans to come on earlier is a bad idea.......Roger.

Who told you that? I have been programming/tuning these cars for years. That is debatable regarding increased wear. A 180 thermostat is what these cars generally like the best. I have ran all 3 in mine. A 160 ,180,and 195 (stock) thermostat.

 

[gmjunkie]

It is NOT a good idea to install a 'cooler' thermostat. ie. one that opens at a lower temperature. The only effect that would have would be to increase the amount of time that the engine runs before getting to running temperature, resulting in increased wear. As long as it is functioning correctly, the stock thermostat is the right one. Also setting the fans to come on earlier is a bad idea.......Roger.

If it was good enough for the General, It's Good enough for me!~!!

Keep it simple stupid and go from there!~!! I wished I had a $10.00 bill for every time I've encountered a car owner that has had them to every Parts Changer in 3 county's and replaced half the cooling system over a weak 16#Radiator Cap!~!!:L:L:L
These cars run at higher temps for a reason,If everything is right they'll work as the engineers intended!~~!!

 

[larry bud]

If the car is operating at 200F, it doesn't really matter if you have a 160 or 180 thermostat, both will be open anyway. It'll just take a little longer getting from 160 to 180 if you have the 160 in it.

That said, if you live in a cold climate, I think 160 is too cold, as you might not get your engine about 170 if it's 10 degrees outside, which means the hot air coming into the car might not be as hot as you like.

 

[hotmtrsports]

The car's fuel/air ratio is adjusted according to emissions, engine temp, and air intake readings to the computer. If you mess with engine temp like fans and such, the computer is going to think something is or is not satisfied and will be running at the wrong fuel/air mixture. A too lean or too rich condition each have their own premature wear results. Not to mention lower fuel economy.

It's not worth messing with...and for what .2 HP???

Chuck M

 

[birdman11]

The car's fuel/air ratio is adjusted according to emissions, engine temp, and air intake readings to the computer. If you mess with engine temp like fans and such, the computer is going to think something is or is not satisfied and will be running at the wrong fuel/air mixture. A too lean or too rich condition each have their own premature wear results. Not to mention lower fuel economy.

It's not worth messing with...and for what .2 HP???

Chuck M

No, everything else is also adjusted in conjunction when you buy a chip or a custom chip for that matter. Fueling and or air/fuel ratio is also adjusted. The gains with a chip are more like 12-20 hp. Look at the results these guys got with another TPI car. Pontiac Firebird Formula Fastchip Chip Install - GM High-Tech Performance Magazine

 

[birdman11]

The car's fuel/air ratio is adjusted according to emissions, engine temp, and air intake readings to the computer. If you mess with engine temp like fans and such, the computer is going to think something is or is not satisfied and will be running at the wrong fuel/air mixture. A too lean or too rich condition each have their own premature wear results. Not to mention lower fuel economy.

It's not worth messing with...and for what .2 HP???

Chuck M

The computer is not going to think anything. The brain of the computer is the "chip". If the brain/chip is reprogrammed ,then there is nothing that is going to be "not satisfied".

 

[hotmtrsports]

No, everything else is also adjusted in conjunction when you buy a chip or a custom chip for that matter. Fueling and or air/fuel ratio is also adjusted. The gains with a chip are more like 12-20 hp. Look at the results these guys got with another TPI car. Pontiac Firebird Formula Fastchip Chip Install - GM High-Tech Performance Magazine

After reading the article, it took 3 chips. The 1st chip was sent back, then the next 2 chips seemed to work but they had to adjust timing, fuel pressure, etc. So the computer did not compensate for everything. Like I said leave well enough alone. There were a few instances that C4's have come in here and I called Gordon Killebrew for help ( Gordon worked at GM and was responsible for writing service manuals and service bulletins to the Corvette until 1993). This guy knows C4's!!! Every time I called him the 1st thing he asked me was if there was a custom chip in it. If there was, he told me to throw it out and get a stock one in there. He was so against these custom chips for the same reasons I stated.

I don't care if it means adding 12 to 20 HP (which took alot of tweeking outside the custom computer chip's relm), it's NOT worth messing with.

Chuck M

 

[birdman11]

After reading the article, it took 3 chips. The 1st chip was sent back, then the next 2 chips seemed to work but they had to adjust timing, fuel pressure, etc. So the computer did not compensate for everything. Like I said leave well enough alone. There were a few instances that C4's have come in here and I called Gordon Killebrew for help ( Gordon worked at GM and was responsible for writing service manuals and service bulletins to the Corvette until 1993). This guy knows C4's!!! Every time I called him the 1st thing he asked me was if there was a custom chip in it. If there was, he told me to throw it out and get a stock one in there. He was so against these custom chips for the same reasons I stated.

I don't care if it means adding 12 to 20 HP (which took alot of tweeking outside the custom computer chip's relm), it's NOT worth messing with.

Chuck M

Timing and fuel pressure are independent of the computer. That is seperate totally,yet Timing and fueling are still adjustable from within the chip itself though. Fuel pressure can either richen, or lean a mixture out. This same outcome can be accomplished by adjusting the fuel curve or injector constant setting in the chip or bin file. Timing can also be adjusted or re-adjusted in the chip too. They just chose not to burn or try another chip with the timing and fueling adjusted in the chip.

 

[birdman11]

The C4 guy you spoke of probably was asking if there was an aftermarket chip in the car, not a custom chip. Aftermarket chips are the ones to "throw out".

 

[hotmtrsports]

From birdman11:

"Timing and fuel pressure are independent of the computer. That is seperate totally,yet Timing and fueling are still adjustable from within the chip itself."

So you're agreeing with me???

Also:

I'm the one that made the call to that "C4 guy". Out of respect for him, I'll call him by his name, Gordon Killebrew. NO CHIPS OTHER THAN STOCK for him. He went on and on about the shortcomings of any chip other than stock. It was not just a passing remark in his conversations with me.

We can go round and round on this. If you believe in messing with it, that's fine. I was giving my opinion.

An aftermarket chip is a canned "fits all" custom chip, a custom chip is an aftermarket chip that's been fit to a specific parameter. It's still not stock.

I'm for a stock chip period. So you put a different chip in it, then what the heck put higher pressure injectors, then what the heck put lower thermostat, then what the heck adjust fan to turn on early. Let's face it, it's dominoes and before you know it, reliability goes out the door. Then one of these days you or somebody that buys it has problems and everything goes back to stock. I've done it both ways.

Chuck M

 

[gmjunkie]

From birdman11:

"Timing and fuel pressure are independent of the computer. That is seperate totally,yet Timing and fueling are still adjustable from within the chip itself."

So you're agreeing with me???

Also:

I'm the one that made the call to that "C4 guy". Out of respect for him, I'll call him by his name, Gordon Killebrew. NO CHIPS OTHER THAN STOCK for him. He went on and on about the shortcomings of any chip other than stock. It was not just a passing remark in his conversations with me.

We can go round and round on this. If you believe in messing with it, that's fine. I was giving my opinion.

An aftermarket chip is a canned "fits all" custom chip, a custom chip is an aftermarket chip that's been fit to a specific parameter. It's still not stock.

I'm for a stock chip period. So you put a different chip in it, then what the heck put higher pressure injectors, then what the heck put lower thermostat, then what the heck adjust fan to turn on early. Let's face it, it's dominoes and before you know it, reliability goes out the door. Then one of these days you or somebody that buys it has problems and everything goes back to stock. I've done it both ways.

Chuck M

ding.Ding,DING..............We Have a "WINNER"!~!!

I'm No "Gorden Killebrew" But I have conversed with him hundreds of times over the last 30 years since the C4's came out!

The man is a Hands on Walking Talking Service Manuel when it comes C4 Corvettes,He can fart more Critical Information than most will ever comprehend!~!!

 

[Dad]

ding.Ding,DING..............We Have a "WINNER"!~!!

The man is a Hands on Walking Talking Service Manuel when it comes C4 Corvettes,He can fart more Critical Information than most will ever comprehend!~!!

If that was to be his way of delivering information would it be called "Air Mail"?

I'd sure like to meet him some day but not that way............:L

 

[hotmtrsports]

I've got ALL of Gordon Killebrew's test equipment and books. Every time I bought them, it was at Corvettes at Carlisle and the deal was I could bend his ear for as long as he could stand it. His wife is just wonderful and extremely helpful.

I haven't seen them around the last few years.

Knowing him, the only time he will really retire is if he is bedridden, he's so into the Corvette world!!!

Chuck M