2001 chevy cavalier overheating

[carnewbiee]

I have a 2001 Chevy Cavalier, 66k miles.

The trouble I am having is it is overheating. I start up the car, the temperature gauge creeps to 1/4 mark in a normal manner, goes to 1/2 mark (195 F) normally as well (takes 5-6 minutes when idle) and then starts going past 195 F. I noticed that when I do this with the car idle, the car occasionally sputters a bit around 195 F, as if it wants to turn off.

I have replaced the thermostat.

After replacing thermostat, I refilled the coolant to the top. I noticed that by the time the car got past 195, the coolant level dropped to the FULL line (bit below the top) and didn't drop after.

I never saw any black oil foam in the coolant reservoir. Neither did I see coolant foam on engine oil dipstick. I also don't notice any visible leaks. I don't notice sweet anti-freeze smell. I am not sure about white smoke from tailpipe, I could be wrong but it doesn't really look white to me.

I have bought four new spark plugs to replace, as I plan to do a compression test to check for head gasket issues.

Can anyone think of other (easier) ways to troubleshoot this?

[J-Ri]

Does it overheat while driving as well? It may be the cooling fan isn't coming on if it's only getting hot at idle. How hot does it actually get? As the sensor and wiring ages, the gauge can get less accurate (from corrosion) and the gauge itself can go bad too. Check the ECT reading with a scan tool. The fans should come on at 222 degrees F, which from what I've seen looks like about 205 on most gauges. They're designed so that in the normal range they don't move much. The drop in coolant level is normal, when the thermostat opens you get some air that comes out of the system. As long as it doesn't get much lower, you're fine for leaks. A small drop is normal, as there may be small air pockets left in the system that will come out as you drive it.

For the sputter, it's hard to say. Check for any codes if the spark plugs don't fix it.

[carnewbiee]

I will get an OBD to scan for codes... could be that there is a "pending code".

It overheats within half a mile when driving... gets past 3/4 mark (250 F, I think) and seems like it can go all the way to red. I haven't checked if the fan comes on when it goes past 3/4 mark. I don't know if I want it to go that far as I have heard it can take many miles of the engine.

For the compression test, should I remove all the spark plugs at once? or do it one by one? I have heard/read of both ways? Also, should I remove the spark plug hot because the compression test says remove plugs after warming up the engine to normal temp.

[manicmechanix]

Originally Posted by carnewbiee

I will get an OBD to scan for codes... could be that there is a "pending code".

It overheats within half a mile when driving... gets past 3/4 mark (250 F, I think) and seems like it can go all the way to red. I haven't checked if the fan comes on when it goes past 3/4 mark. I don't know if I want it to go that far as I have heard it can take many miles of the engine.

Does the cooling fan come on? Also does your ehater put out hot air? Yeah put a scanner on it. The car mightnot be actually overheating if the guage or sender is incorrect.

For the compression test, should I remove all the spark plugs at once? or do it one by one? I have heard/read of both ways? Also, should I remove the spark plug hot because the compression test says remove plugs after warming up the engine to normal temp.

Remove all the plugs with the engine cool to do the compression test. Pull the fuel injector use and ign fuse so you won't have or spark or fuel while testing compression. It's not necessary for the engine to be hot to test compression as long as your battery and starter are strong.

[carnewbiee]

Originally Posted by manicmechanix

Does the cooling fan come on? Also does your ehater put out hot air? Yeah put a scanner on it. The car mightnot be actually overheating if the guage or sender is incorrect.

Haven't seen the fan in front of the radiator come on yet. But I have also heard that it takes a while to get it to come on when idle.

The heater does put out hot air.

[J-Ri]

After you get the scan tool, let it idle and watch the fan as the temp approaches 222 degrees, should turn on there. If not check the fuse and relay, but most often the fan itself is bad.

If you're driving and it overheats, I'd bet the gauge is inaccurate, you should have plenty of airflow through the radiator over 15 MPH (especially in this cold). You have a new thermostat and if the heater works the water pump works.

[joeuser742]

Weird, I have a 2002 and I just noticed mine creaping up just over the 195 mark also, which I've never seen before. The fan does come on. Have you tried flushing the coolant? Could be a clogged radiator? Water pump? Is the engine louder than usual, whining noise?

[carnewbiee]

I couldn't get my hands on an OBD II yet... so no results on pending codes.

I did an engine compression test. This is how I did it:

Started the car, warmed it upto 195 F, removed spark plug wire, and spent some time cleaning around the plug before removing it. Then I removed one spark plug (left rest 3 installed), and did compression test for Cylinder 4.

Cylinder 4 - 180 psi, engine didn't turn over (car didn't start), engine was at 150 when I did this because I spent some time cleaning
Cylinder 3 - 162 psi, engine didn't turn over (car didn't start), engine wasn't warm at all because I spent sometime cleaning

Now, I cleaned the area around the spark plug first, than I restarted the car and let it idle to 195 F, and did compression test for cylinder 2 and 1

Cylinder 2 - 210 psi, engine turned over (car started), engine was at 195 when did this
Cylinder 1 - 210 psi, engine turned over (car started), engine was at 195 when did this


I think cylinder 3 and 4 are bit low because the engine was not as warm and the car didn't start? How do the numbers look? Head gasket failure?

Also, now the car doesn't get past 195 F so easy, it takes it a while when idle and gets to 198 F at best. Not sure why?

I moved the car from garage to driveway 5-10 times and notice the fan came on. I redid this couple hours after installed 4 new spark plugs and the fan didn't come on. I will take it on the road tomorrow to see if it overheats.

Btw, why is the water pump ok if the heater works?

[J-Ri]

We're not really concerned with pending codes, just comparing the ECT sensor to what the gauge reads.

Ideally you should have done the compression test cold, throttle held wide open and with all the plugs removed. Also a good idea to remove the fuel pump relay with the car running and let it die, that way you're not injecting fuel which will wash the oil off the cylinder walls. Having it warmer for the last two could have affected the numbers a bit. But those numbers are very good, I think 150 PSI with the lowest cylinder not less than 75% of the highest is what they say.

The water pump is OK if the heater works because it circulates water through both the radiator and heater core. Flow through heater core=flow through radiator (unless it's plugged up).

Edit: I just re-read that and saw that the engine started for the higher compression readings. They're that high because the engine pulls in much more air running than just cranking. Don't know why it didn't start the first two times, but you need to disable the engine from starting before doing a compression test. Having it at higher RPMs makes differences less apparent, any leaks don't affect the pressure as much as if the engine is cranking slowly.

[carnewbiee]

I would find it hard to believe that the numbers go down to 15-30 psi if I do it cold? I was under the impression that 150+ psi indicates that it is not a head gasket failure... but if you think I should redo cold, I can try that. I don't know where the fuel pump relay is, fuel injector fuse, and ignition fuses are... so I let the car start. I didn't think it would affect results a lot.

Any other easy to do ideas?

[J-Ri]

Doing it hot, the rings are going to seal better than cold. I'm not sure of the difference, as I've never done it hot and cold on the same vehicle for comparison. The big reason for the 210 PSI was that the engine started, try it again cold, and pull the fuel pump relay to keep it from starting, and see if you have more even numbers. You should unplug the ignition module too, an open circuit isn't very good on the coils.

I'd wait until you get the scan tool before doing anything else, I think the problem is most likely with the gauge.

[carnewbiee]

Originally Posted by J-Ri

I'd wait until you get the scan tool before doing anything else, I think the problem is most likely with the gauge.

Not that I know about cars, but based on one of your response, I am beginning to think it is clogged radiator. The water pump works, and the gauge goes past 195 sometimes quick sometimes takes a while. Maybe there is some clog somewhere.

[J-Ri]

I wouldn't say it couldn't be plugged, but we're at roughly the same latitude. Assuming it's been in the 20's (F) there, you should be able to let it idle with the heater on high and it shouldn't ever overheat. I start my car 10-20 minutes before I leave home, any time in that range when I get in the ECT reads 150 degrees on the gauge. I usually get to work before the boss gets there to open the shop, and the temp drops back down while I'm sitting there idling. There's a good chance that I'm burning a bit more fuel than you too... unless you have some mods

If the fans do come on, but don't come on when it "overheats", it almost has to be a gauge/sender malfunction. I really think your next step should be to confirm that the ECT is actually high. A low cost alternative to a scan tool is a meat thermometer taped to the upper radiator hose with reflective silver tape... maybe 5 wraps around the thermometer to try to keep some heat in. It will probably read 10-20 degrees cooler than the ECT sensor is, but if it shows 190 degrees and the gauge shows red, you have your answer.

[Jessicasdd]

Were you able to get this fixed? I just had this same problem with my car and I changed the Temperature Sensor and the car is fine now. Just a suggestion if you are still having an issue.

[Jessicasdd]

NO this car is still not fixed. It is still overheating. I put anti-freeze in it and it runs for 3 days and tries to overheat again and the anti-freeze is gone. I see no evidence of it ever leaving the car. But then again this happens while I am driving, not parked. I changed the temperature sensor a couple times. There are actually 2 or 3 different temperature sensors and they have all been replaced. One in the air line on top - air temp sensor, one in the anti-freeze, and another one in the lines down under the anti-freeze container, I think.

Anyway, any ideas?