Cavalier is overheating

Hi,

I have tried reading some of the other threads regarding this but can't quite find one that fits.

I have a 96 cavalier 2.2L. It just started over heating by it self yesterday not sure why. If the car runs to long it goes all the way up to red. The heat is working at first but once it starts to over heat the heat stops working and starts blowing cold air instead.

It has been leaking engine coolant for a while but I am not sure why and haven't been able to figure it out. It is a very slow leak so I just fill it up every so often. I put in some gunk to fill up holes that is put directly into the overifll tank of the rad to try and stop it. This usually stops it for a month or two but eventually it starts leaking again. When it first started to overheat I checked the overfill tank and noticed it was empty so I filled it up because I thought this might be the problem. The light was not on that says it is low on engine coolant which is weird because it usually turns on. Once I put more in it still overheated. Also the check engine light came on with the code P0440. The code does not relate to the rad or anything just trying to give as much info as possible.

I was wondering if it could be the thermostat? Or that the overfill tank is blocked to the rad so there is no engine coolant in there either.

ANy help would be appreciated.

How many times have you added stop leak (gunk to fill holes)????

Could be block radiator, thermostat. Symptoms point to low on coolant.

Do a compression test for blown head gasket. Post compression for each clyinder.

How many miles on engine???

How many times have you added stop leak (gunk to fill holes)????

Could be block radiator, thermostat. Symptoms point to low on coolant.

Do a compression test for blown head gasket. Post compression for each clyinder.

How many miles on engine???

Theres around 115,000 miles on it. How would i perform a compression test?

I have used the stop leak around 4 times over the past year and a half.

Today when i tried the heat it did not work at all.

There is coolant in the overflow tank but maybe there is none in the rad it self, how would I test this? And could a brokenthemrostat block the coolant from going into the rad?

To perform a compression test, remove all the spark plugs and disable the fuel injection. Thread a compression tester into each cylinder (one at a time) and crank the engine with the throttle wide open until the pressure stops rising.

Stop leak should only be used in an emergency, it hardens when exposed to air. That means it may seal the leak as it passes through the hole, but if it doesn't, the coolant gets lower and lower, and the stop leak hardens inside the block, radiator, and heater core as air is introduced into the cooling system. (not good)

Heat not working when the ECT is high points to air in the cooling system, which is why the compression test to confirm a leaking head gasket was suggested. (although a small leak may not show up in a compression test, as the variation allowed can hide a small)

If there is coolant in the reservoir, there is coolant in the radiator. The big hose out of the bottom of the reservoir "T"s into the lower radiator hose, and gravity explains the rest.

The thermostat is what regulates the flow of coolant into the radiator, but if it was stuck shut causing the engine to overheat, the heater would work very well. When the heater stops working like that, it means there is no (or very little) coolant in the heater core

Thermostat is the thing to check here. You said you have put in the gunk crap (which i recommend to never do) because it only clogs up everything including your thermostat.

WHen your thermostat can not open, it will over heat your car in no time after start. Also that gunk crap can clog up a heater core easily restrcting flow dramatically causing no heat to blow out, and your engine can over heat that way.

Thermostat is the thing to check here. You said you have put in the gunk crap (which i recommend to never do) because it only clogs up everything including your thermostat.

WHen your thermostat can not open, it will over heat your car in no time after start. Also that gunk crap can clog up a heater core easily restrcting flow dramatically causing no heat to blow out, and your engine can over heat that way.


Clearly that was a big mistake putting it in. Just lucky it wasn't a new car/more expesnive! I changed the thermostat today but still it is not working properly. It overheats and also the heat works sometimes, but most of the time it does not. Could it be the water pump? I want to try the cheap fixes first and if they don't work I'll take it in to get looked at and decide.

I changed the water pump about 1.5 years ago also.

could def be the water pump.. sometimes a sign of a bad water pump is hearing a chirping type noise which is coolant going through the veins of the pump.

But that could be a good step to check at this point. Again that crap you put in can damage the pump.

id start by draining the coolant system first and starting over with a 50/50 mix and make sure all the air is out. could be a air pocket somewhere. just so that way there's a good base line. I'd even run a thing of flush through it. i know there's a back flush kit you can get. i don't know if its any good or if it will work.

As for the original leak, take a close look at the head gasket. This is a common leak point on earlier 134" engines. There was a TSB and early recall on these:

http://mysite.verizon.net/strey/files/HeadGasket3.jpg

could def be the water pump.. sometimes a sign of a bad water pump is hearing a chirping type noise which is coolant going through the veins of the pump.

It could not be the water pump, water pumps don't fail intermittently, so it wouldn't make the heat not work occasionally. The chirping noise water pumps make is from the bearing, not the "veins", water pumps do not have veins, they have an impeller which some water is always constantly "slipping" past

thanks for all of the information and suggestions, i am going to try to get to them asap! just very busy at the moment.

One more thing that is happening now is when it overheats it backflows out the top of the overfill tank cap. I assume that this means it is blocked somewhere? or an air pocket could cause it? The coolant is not hot and the overfill tank coolant is not either. The heat seems to work now, and if the heat works does this mean the water pump is working?

thanks for all of the information and suggestions, i am going to try to get to them asap! just very busy at the moment.

One more thing that is happening now is when it overheats it backflows out the top of the overfill tank cap. I assume that this means it is blocked somewhere? or an air pocket could cause it? The coolant is not hot and the overfill tank coolant is not either. The heat seems to work now, and if the heat works does this mean the water pump is working?

When it overheats, the water in the block boils which forces coolant out. An air pocket could cause that, and boiling makes an even bigger air pocket until it cools. If the coolant is not hot, by definition it is not overheating. Your gauge could be off (connect a scan tool and read ECT, or use an infrared thermometer to confirm). Also pressure test your cap, it may not be holding pressure, which would cause the coolant to boil at a much lower temperature, and would allow coolant to flow out much easier. If the heater works, the water pump is working. I have never seen a cavalier water pump stop moving water. Some vehicles with plastic impellers (Fords especially) will have fins break off, but I believe the cavaliers have metal fins, I know the 2.4 does. I have never replaced a water pump on a 2.2L, so that says something about them.

The first thing I would do is flush the cooling system, then pressurize it so you can see where any leaks may be. You may have more than you know about, once that stopleak is out of the system. Once you find them, fix them. That will probably fix the overheating, but with all the stopleak in there, it is possible you plugged the radiator and block. You'll just have to see once you fix it.

When it overheats, the water in the block boils which forces coolant out. An air pocket could cause that, and boiling makes an even bigger air pocket until it cools. If the coolant is not hot, by definition it is not overheating. Your gauge could be off (connect a scan tool and read ECT, or use an infrared thermometer to confirm). Also pressure test your cap, it may not be holding pressure, which would cause the coolant to boil at a much lower temperature, and would allow coolant to flow out much easier. If the heater works, the water pump is working. I have never seen a cavalier water pump stop moving water. Some vehicles with plastic impellers (Fords especially) will have fins break off, but I believe the cavaliers have metal fins, I know the 2.4 does. I have never replaced a water pump on a 2.2L, so that says something about them.

The first thing I would do is flush the cooling system, then pressurize it so you can see where any leaks may be. You may have more than you know about, once that stopleak is out of the system. Once you find them, fix them. That will probably fix the overheating, but with all the stopleak in there, it is possible you plugged the radiator and block. You'll just have to see once you fix it.


alright thanks! Is it hard to flush the cooling system? I am sure I can figure it out if its not to hard or is it worth bringing into the shop for this kind of job?

Probably not too hard... we have a flush machine at the shop, so it's really pretty easy. I did see a (Prestone?) flush kit in an Advance Auto a while back, looked like it had a bottle of flush chemical and a garden hose adapter. You really should recycle used antifreeze, so it may be better to take it to a shop... up to you.

With our machine, you remove whichever end of the upper radiator hose is easier to remove, install the adapters for that size hose between the hose and the rad/water outlet and add the chemical. Then you start the engine and let it get to operating temperature and then run for 15 min after the thermostat opens. Shut the car off, then you close the valve in the adapter's hose and the machine pumps pre-mixed antifreeze backwards into the system. If it's noticeably dirty, use plain water until it comes out clean, then start the antifreeze mix.

Probably not too hard... we have a flush machine at the shop, so it's really pretty easy. I did see a (Prestone?) flush kit in an Advance Auto a while back, looked like it had a bottle of flush chemical and a garden hose adapter. You really should recycle used antifreeze, so it may be better to take it to a shop... up to you.

With our machine, you remove whichever end of the upper radiator hose is easier to remove, install the adapters for that size hose between the hose and the rad/water outlet and add the chemical. Then you start the engine and let it get to operating temperature and then run for 15 min after the thermostat opens. Shut the car off, then you close the valve in the adapter's hose and the machine pumps pre-mixed antifreeze backwards into the system. If it's noticeably dirty, use plain water until it comes out clean, then start the antifreeze mix.


Kk well got the system flushed. Also installed a new thermostat and had just water in the car and the thermostat opened! So we flushed it again and put in 50/50 but now the thermostat won't open anymore, and I have no idea why. The whole problem seems to be the thermostat nto opening when there is coolant in the system.

I had a 96 Beretta with the 2.2L, and I got 4 bad thermostats in a row (except mine stuck open). If it opens with water, it should open with coolant... did you let it run until it almost overheated? Sometimes (but very rarely) a new thermostat will stick mostly shut until it opens/closes a few times.

Yeah sometimes when you refill the cooling system and don't have all the air out yet, the thermostat won't open till the car gets pretty hot and it might take a while for it to pop open. Or you could've gotten a bad thermostat as was said. It happens.

I had the same problem with my old car (87 Maxima) turned out to be the thermostat which someone tried dumping gunk in the fucking radiator which caused it to fucking explode. I ended up replacing the whole radiator system and it worked fine after, cost me about 400 bucks but it was well worth it. The cap was also replaced.