Help! Lumina overheating!

Hi my 1995 lumina overheats when in low speed traffic and the gauge seems to stay in place when at a total stop, like if the gauge is more than half-way over and I'm at a total stop the gauge will just sit there.. The only way the gauge goes back down is when driving at high speed.. what could it be? I have made it so the cooling fans under the hood are on consistantly, it still has the same problem, I took it to a local mobil shop and they said it seems to be bleeding out the air and you can see bubbles in the coolant tank. They said it might be a head gasket, I really hope it isn't, has anyone else had this problem? and if it is a head gasket is there any way to find out 100% sure without taking the whole engine apart?

did they bleed the air out of your coolant system? does it keep recurring?

if you keep getting air into the coolant system, it just might be the head gasket as it would take alot of pressure to push air into the coolant (your coolant system is pressurized when it's hot, 15psi or so). wouldn't be an intake gasket as that is a vacuum, it would pull coolant into the intake if anything.

what else could push air into the coolant other than the high compression in your cylinders? ntohing i can think of.

do you have enough antifreeze to prevent boilover/steam from occuring?

one other idea... when your car is cooling... perhaps there is a leak somewhere that is letting air bleed into the coolant system as the pressure is stabilizing?

and do you have any sludge buildup in your coolant recovery tank?

just brainstorming

did they bleed the air out of your coolant system? does it keep recurring?

if you keep getting air into the coolant system, it just might be the head gasket as it would take alot of pressure to push air into the coolant (your coolant system is pressurized when it's hot, 15psi or so). wouldn't be an intake gasket as that is a vacuum, it would pull coolant into the intake if anything.

what else could push air into the coolant other than the high compression in your cylinders? ntohing i can think of.

do you have enough antifreeze to prevent boilover/steam from occuring?

one other idea... when your car is cooling... perhaps there is a leak somewhere that is letting air bleed into the coolant system as the pressure is stabilizing?

and do you have any sludge buildup in your coolant recovery tank?

just brainstorming

I'm not 100% sure if the problem is air in the coolant system, the person at mobil told me that it was indeed bleeding out the air, there is enough antifreeze there. Do you think it could be the water pump? any way to check?

i thought water pumps only need replacing because the seal fails. that's an iron impeller, so long as your pulley is spinning, that impeller is spinning too. stuck thermostat? that is a *mother* to get to. To check flow... I don't know... be nice if the radiator hose had a window where you could see the flow

BTW, if you think there's air in your cooling system, you could do the following to take it out.

Find the bleeding valve (easily accesible under your hood) which is usually located at the top of a thick black hose near the radiator.
Get a wrench that will unscrew the valve.
Fill the coolant reservoir to the FULL level if needed.
Drive the car until it heats up to the MID or more.
Park it but don't let it cool down.
Open the valve slightly until a stream of (green) liquid pours out. Don't worry if it gets on any parts (it's harmless).
Close the valve and let car cool for a bit.
Test drive it!


I had the same problem and I didn't know why I kept getting air in the system. Now I do this once a month during the summer and I get by with my 95 eagle vision.

You say lumina.
I have a 95 APV with a 3.1 and the thermost was bad. Temp up and down depending on speed.
Swapped it out in about 2 minutes. Its right on top at end of hose.
Don't know what you have though.

I switched out the thermostat already, it didn't help :(

My first guess was the thermostat. It would not be a water pump, because if a water pump went, all you would have to do is start it, and let it idle for about 5 mins, and it would be overheated, the fact that you can drive it, tells me that it is indeed a head gasket. Sorry to tell you this, but I had a car that kept doing the same thing, and I sold it before the problem got too bad, and before I did any repairs, I found out two months later, the buyer had a new head gasket put in it. Good luck. I head the 3.1's are said to not have the best head gaskets.

I had the same problem when I purchased my previously owned 1994 Lumina APV w/ 114,000 miles. I changed the coolant temperature sensor and did a radiator flush. Not the 10 minute flush but the "cleaning" which requires one to leave the cleaner in the system between 3 to 6 hours of operation. A lot of sludge came out. I believe the radiator was partially plugged. It is worth a try before you spend a lot of money at the mechanic shop. Hope it helps.

The coolant temperature sensor is located at the rear of the engine next to the oxygen sensor, just behind the bracket that holds the ignition coil.

man now the car doesn't even start anymore, a belt snapped and I replaced the belt but all i hear is a "clicking" noise coming from the hood. a friend of mine told me it could be the ac compressor belt that is causing a problem? im probably gonna have to junk this car :(

did your water pump seize up and cause the belt to break?

this tip helped me quite a bit, thanks!

Sorry to bump this back up but I've been having the same problem with my '95 lumina. A couple years ago, I had the thermostat replaced and the coolant tank flushed out after having overheating problems. Since then its only overheated a couple times, none of them recently. Today on my way to work and back I could smell oil burning and after checking under the hood, noticed that the coolant tank had foamy bubbles in it and the coolant had turned dark black (from sludge?) from the normal green color. Could this be a head gasket problem or worse?

Your coolant is green? I have factory installed Dex Cool in mine still, And its red. I think I'm going to get it flushed, any ideas on what I should put in? Dex Cool again to be safe? Thanks

Slim_D ouch I think you may have blown a head or intake gasket! oil is blowing past the gasket and getting into your coolant.

I had just changed my intake gasket myself 2-3 months ago, I caught mine in time. I still have reservations about using DexCool [google: DexCool class action lawsuit] - many people think it is corrosive... But I'm using it anyway until I know for sure.

dont rule out your water pump, my 96 3.4L has overheating probs, changed the therm., nothing, I dont think any sensors are out, I just pulled the pump today since haynes says to squeeze the upper hose and let go while running and I should feel a fluid surge, I felt nothing. The water pump is not squeeling, or leaking, BUT it was turning only with some effort, which to me indicates that the fluid was circulating, but barely, I will find out tomorrow when I put a new one in, if thats not it, I dont know what i'll do