Corsica 3.1L - Overheating

[ITR000]

I just purchased a used 1990 LTZ (3.1L V6), I needed a daily driver / winter beater and this car was in great condition. Rust checked every year with only 69,850 KM's (I am from Toronto, Canada) and only 2,900 dollars. Anyhow, the thing runs at 3/4, which concerns me. I decided to give the car a tune up, (new wires, new plugs, new fuel filter, new PVC valve, new air filter, new rear shocks and mounts (old ones were leaking), new rad, new t-stat, new coolant sensor, new upper and lower rad hoses. Anyhow, the stupid thing still runs hot! I don't under stand it, at idle it climbs to 3/4 and the fan fires up, stays on for 40 - 90 seconds, then its off... temp goes down a tad but not much. I called a GM stealership; the service rep is telling me the gauge should be sitting 1/2 or a tad higher but not 3/4.

I am concerned since, if the head gasket is cracked (which from what I have read is common on this engine) the temp would run hot. I do not think the head gasket is cracked since I do not see bubbles forming in the coolant tank. The plugs would be fouled; my old ones were in good condition.

Can anyone offer any help. It scares me to drive the thing and have the engine overheat, which is bad news.

[SappySE107]

RE: Corsica 3.1L - Overheating

Ive heard of someone having their belt wrapped around the water pump instead of pressing against it on the side. This will make it run backwards and get really hot. Since the fans come on, its probably correct but there are 2 sensors for the temp, one on the head and one on the intake manifold. Did you replace both?

Do a pressure check, and also, make sure you bleed the coolant lines. There should be a spot to bleed air out, though im not familiar with the L body cooling system either.

[ITR000]

Re: RE: Corsica 3.1L - Overheating

Ive heard of someone having their belt wrapped around the water pump instead of pressing against it on the side. This will make it run backwards and get really hot. Since the fans come on, its probably correct but there are 2 sensors for the temp, one on the head and one on the intake manifold. Did you replace both?

Do a pressure check, and also, make sure you bleed the coolant lines. There should be a spot to bleed air out, though im not familiar with the L body cooling system either.

I only changed the coolant temp sensor (top of motor near t-stat housing), I did not change the sensor on the head (back of motor) I thought, I dont want to change this and that and have the problem still occur.

The rad was changed and both upper and lower hose, so the coolant lines were bleed at that time. Pressure check, explain, please.

[SappySE107]

RE: Re: RE: Corsica 3.1L - Overheating

You can rent the setup at autozone. It replaces the radiator cap, and you pump it up to 15 psi. You can then check for external leaks visually or watch to see if the pressure either doesn't build or drops slowly. It should hold its pressure though.

I never remember which sensor goes to the gauge, and which goes the ECM. The problem could be no problem at all though.

[ITR000]

Re: RE: Re: RE: Corsica 3.1L - Overheating

You can rent the setup at autozone. It replaces the radiator cap, and you pump it up to 15 psi. You can then check for external leaks visually or watch to see if the pressure either doesn't build or drops slowly. It should hold its pressure though.

I never remember which sensor goes to the gauge, and which goes the ECM. The problem could be no problem at all though.

AutoZone, we don?t have them in Canada. I guess I can take the car to a local mechanic; the charge for a pressure check can?t be that much. Anyhow, the sensor located at the t-stat housing sends signal to the ECU, the sensor (which I did not change) located on the head (lower rear of engine) sends signal to the gauge. I don?t think the gauge is bad, I used an infrared temp gauge and pointed it at the t-stat housing, the temp was 95c which is 205f, the gauge at this time is reading 3/4 (which is about correct). Once the fan engages and is on between 40 - 90 seconds before switching off, the temp on the t-stat housing is 85 and the temp gauge in the car is slightly below 3/4. The service manual is indicating if you have a Corsica with a temp gauge (if you have a temp gauge then you do not have an overheating dash light) and the gauge is pass the 1/2 way mark, the car is overheating.

I am baffled. It cant be a cracked head gasket or block. The intake gasket looks fine (not dripping coolant). Unless the water pump is bad, but I do not hear any bearing noise and as mentioned there are no signs of coolant leaking. What other ways can I check that the water pump is flowing the coolant properly?

[SappySE107]

RE: Re: RE: Re: RE: Corsica 3.1L - Overheating

The fan turns on at 106 degrees C I believe. Im not familiar with your gauges, but the grand prix gauges are pretty lame. Half way between 2 numbers is not the same has the average of both numbers for temp. Find out what the computer is seeing as far as temp goes. 205 F is not overheating.

[ITR000]

Re: RE: Re: RE: Re: RE: Corsica 3.1L - Overheating

The fan turns on at 106 degrees C I believe. Im not familiar with your gauges, but the grand prix gauges are pretty lame. Half way between 2 numbers is not the same has the average of both numbers for temp. Find out what the computer is seeing as far as temp goes. 205 F is not overheating.

I guess I will change the sensor on the head (the unit that sends signal to the temp guage on the cluster.

Man this car has already cost me 1200 in repairs and I haven driven more then 100 KM's in 2 weeks!!! I thought a 3.1 V6 with only 69 K's would be fairly problem free. Whats the deal? Are these engine lemons?

[SappySE107]

RE: Re: RE: Re: RE: Re: RE: Corsica 3.1L - Overheating

Yes, we built a site based on lemons.

I think your engine is fine. It may have 69k on it but its 15 years old as well. Head gaskets don't usually go bad. Only the gen 3s had issues really, and that was a poor intake gasket design. Unless your motor has a lot of deposits in the coolant passages, there is no real reason for you to have any overheating problems. I honestly have no faith in the gauge, especially when you are telling me the stat housing was reading 205 degrees.

[ITR000]

Re: RE: Re: RE: Re: RE: Re: RE: Corsica 3.1L - Overheating

Yes, we built a site based on lemons.

I think your engine is fine. It may have 69k on it but its 15 years old as well. Head gaskets don't usually go bad. Only the gen 3s had issues really, and that was a poor intake gasket design. Unless your motor has a lot of deposits in the coolant passages, there is no real reason for you to have any overheating problems. I honestly have no faith in the gauge, especially when you are telling me the stat housing was reading 205 degrees.

Well a infrared temp gun pointed at the t-stat housing is telling me 95 degrees... If the guage is not a good measure, why is the dealer telling me that this should be dead center?

[SappySE107]

RE: Re: RE: Re: RE: Re: RE: Re: RE: Corsica 3.1L - Overheati

maybe it should be, im just telling you that if you have 100 and 200, and the needle is half way, it may not be 150. I don't know what your gauge looks like. I go by the ECM on my car.

[ITR000]

Re: RE: Re: RE: Re: RE: Re: RE: Re: RE: Corsica 3.1L - Overh

maybe it should be, im just telling you that if you have 100 and 200, and the needle is half way, it may not be 150. I don't know what your gauge looks like. I go by the ECM on my car.

Ok, thanks. I will check it out. If a scan tool is connected to the ECU can it give me a accurate temp?

ECM explain, please.

[854x4s15]

o.k. I had the same problem with my '93 Corsica. Did the collant pressure check and all that and came up fine. These engines call for 5W30 motor oil. Now, what i did was changed to 10w30 for summer time. Result lower opperating temps. The guage never goes past half. I did this when i reached 120,000 kms. That was about five years ago and never had another cooling problem since so i'm assuming this worked.
One other thing to check is if it might be air locked this would also cause it to overheat. I hope this helps as i've had my Corsica for about 8 years now and it's probably one of the better cars i've ever owned.

[ITR000]

o.k. I had the same problem with my '93 Corsica. Did the collant pressure check and all that and came up fine. These engines call for 5W30 motor oil. Now, what i did was changed to 10w30 for summer time. Result lower opperating temps. The guage never goes past half. I did this when i reached 120,000 kms. That was about five years ago and never had another cooling problem since so i'm assuming this worked.
One other thing to check is if it might be air locked this would also cause it to overheat. I hope this helps as i've had my Corsica for about 8 years now and it's probably one of the better cars i've ever owned.

Well, since I bought the car used, the first item I changed was the oil and filter. I of course used what the owners manual called for - 5w30. There is only 300 KM's on the oil and filter. I will wait until 1000 KM's and I will chnage to 10w30 (not quite sure why slightly thicker oil will effect engine operating temps (assuming the temp guage on the dash is accurate)) In the meantime I will perform a pressure check, if this shows a issue, the oil will not make any difference. I dont think anything is cracked, since, I dont leak coolant, no bubbles in the coolant tank. As well, I have been checking the oil dip stick and its not frothy, which would indicate coolant mixing with the oil. Also, I have pulled the oil filler cap three or four times and the inside is dry, no coolant at all. I also added some Water Wetter from Redline in the coolant today, we will see what happens. I will post my findings as I un-cover them.

Besides this issue, how is the Corsica as a car, reliable or problematic? How is the 3.1 V6 engine, mine is a 1990 what gen is this?

THANKS for all the help guys!

[bszopi]

If the thermostat doesn't open until 195ºF, how is 205ºF at the thermostat housing overheating?

[ITR000]

If the thermostat doesn't open until 195ºF, how is 205ºF at the thermostat housing overheating?

Its not, but the dumb gauge on the dash is 3/4's of the way up. This is odd; since the owner?s manual is indicating that if the gauge is over 1/2 way it?s overheating. Now, the gauge could be screwed (I did not change this sensor), however, I don?t think it is. If the gauge was bad, I am assuming I should see the gauge act erratically, meaning, it should drive up then fall then back up, etc, etc, etc... I do not see these conditions.

Yesterday evening I was on the highway, speed 110 - 120 KPH, RPM's 2500-2900 and the gauge is reading a tad below the red (red is 125). This is concerning me, since last night the outside temps in Toronto were 8 degrees. If its overheating now, what happens mid summer?