John Gosselin

Just recently my 2001 Cavalier (2.2L) started to run hotter than usual & while it hasn't actually boiled-over (or died on the road), the temp gauge did border on the RED zone for brief periods. I'd pull-over, stop for a for minutes, then resume - it would still run HOT, but I could get where I was going.

I'm the original owner of this car & I've always taken "good care" of it; it's got 161,000 miles, so initially figured that maybe it was just the DEX-COOL which was worn-out (should've changed that about 150,000 according to the manual, but it NEVER had this overheat issue until the last month or so . . .). I drained & changed the DEX-COOL & changed the thermostat as well - an easy enough thing to do if you've already drained the system, and I've changed car thermostats before enough to know how to do so (plus, I keep the Chilton's Guide nearby for reference as well).

At first, it seemed that these two things had done the trick, but after a week or so, (and the weather has been getting WARMER . . ) the issues have returned. When driving on the highway, the engine seems to be running COOLER than it should be - the temp gauge 'hovers' around 145-150 & the heater then only give off "lukewarm" air; as soon as I get off the highway & into city traffic, the temp starts climbing and the heater will then give off VERY WARM air. This is a brand-new thermostat, but could be jammed ????

Also, I'm not sure if the cooling fan is working properly - when I first refilled the fluid & did the initial "testing", the fan DID go on as it should have, but I still get the feeling that it's NOT working as it should.

Anyone have any good ideas here ? I try to do as much of my own car work as possible, but will pay to get things done when I can't handle the job. I've been out-of-work for a while however & $$ is tight right now, else I'd probably have taken it to the dealer by now (something I usually TRY to avoid doing).

Any help & suggestions anyone can offer here will definitely be appreciated.

John Gosselin

I probably should have added that in all other respects, the car is running well & not giving "symptoms" of any other mechanical problems.

EinST

Welcome to the forum. I guess a couple of things could be going on. The cooling fan may not be running when it should. Do you hear it running at all, like when it gets hot enough or when the A/C compressor engages? Concerning the thermostat, did you put it in backwards, perhaps? Also, did you bleed the air out of the system?

deere john

I had the samething happen to my Cavalier. I found steam coming out of the #1 cylinder which lead to blown head gasket.

John Gosselin

The problem appears to be SOMEWHERE in the electrical feed-back loop which activates the cooling fan (or, in this case, DOESN'T activate it). The fan will run if connected directly to the battery - I tested that - but otherwise, it simply will not go on. The fuses & relays all seem to be OK as well (I know another person w/ the same year Cavalier and she let me "swap" her components briefly into my car & this also had no effect, so I'm assuming that mine [fuses & relay] are still 'Good' as well.)

Have ANY idea what else in the electrical system COULD be causing this ?

Could the problem be in the car's computer - I sure hope not . . . ?

66MagicDragon

I am fighting a similar problem with my 94 Pontiac Sunbird. I came to the conclusion that the relay was bad. But when I went to Auto Zone (and then Advanced Auto) I found that they both came up with the wrong relay (a five pin unit). Didn't matter if they looked it up by the number on the old relay (12077867) or if we went in by year/make/model. I'll be trying Car Quest and Bennet Auto tomorrow.

66MagicDragon

Bennet Auto also had the black plastic 5 pin relay, but they also had a wiring diagram for it. The old unit is a normally open relay. The 5th pin on the new unit allows it to function as a normally closed relay also. The other 4 pins function the same as the old unit. The 5th pin does not get in the way when plugging it into the old harness. There is a blank space where it goes. It cost me $28 but it did solve the problem. The part number on the 5 pin unit is DR1059 RY-282T Made in India.

Segfault

All this does not explain over-cooling OP experienced. If this was my car I'd take out the thermostat and inspect it closely. New thermostat does not mean good thermostat.

mgoshert

Here is some information regarding the 2001 Cavalier according to the National Highway Traffic Safety Administration (NHTSA):
-219 Consumer complaints
-6 Car Recalls
-143 Safety Bulletins
-3 Investigations

These reports can be found here: 2001*Chevrolet*Cavalier*Complaint and Car Reports, Ratings and User Comments

Chuzz

Ditto on checking the thermostat. It sounds like it could be stuck open. Also, you need to have a 50/50 mix of distilled water and anti freeze in your system. If the fan isn't kicking on, the you definitely have either a bad relay or a short you need to trace.