Saw the two recent topics, but I wanted to see if you guys had any additional input on my particular situation.

Car is a 1997 Z24 Cavi, ~125k miles.

Car has been running fine, however I believe the fan has issues. A/C always cycles on and off at idle, but stays on while driving, but that's another story. It also leaks coolant slowly over time (maybe 1-2 quarts over several months), which I think may be a worn head gasket, but it has never affected driving, and I've never seen oil in the coolant or vice versa.

Here's the new problem, which just started Wednesday - under acceleration, the car heats up fast - like in seconds the needle goes from 195 to red zone. While cruising or idleing it comes back to the comfort zone. Car was a little low on coolant, so I filled it up, but the problem is still there. I'm leaning toward t-stat or possibly the water pump going? Maybe even a radiator cap?

Any ideas on where to start, and is a water pump replacement difficult for a guy with hand tools and jack stands?

Thanks in advance~
Tom

First thing to do is, I would recommend doin the cheapest things first, Flush the cooling system, New thermostat, New coolant. Then bleed the system free of air. Also It wouldnt hurt to get a compression test on each cyl, Least that will narrow down if its a H/G, Sounds like a H/G issue. Common signs. Then once do the small trouble shooting is done, Then work on the major if so.

Good Luck.

Wow, just came in here to post a similar problem.

My a/c has been cycling on and off at idle, but works fine while driving.

Also, my radiator fan seems to have stopped turning on. I sat idling and temp got pretty far up, (not to red zone) and it never came on....

Oops, also this is on an 05 sunfire, 58k miles

Some times a common coolant flush and thermostat, Refill coolant can correct youre overheat cooling issues, at most imes the temp sendin unit can get gummed up, Causing it not to read correctly, In which delays the car computer instructed what to do. Like people say preventive maintance can help big repair bills.

I followed the direction in the manual about letting it run with the filler cap off, and now the temp seems to be staying where it should. It hasn't gone up enough now to see if the fan comes on or not like it should though.


A/c compressor still is kicking in and out at idle too.

II'm still going to go ahead and flush out the system tomorrow, since I don't think that's ever been done and soon the car will hitting 59k miles.

Still haven't figured this all out.

Someone said when the a/c is turned on the radiator fan should automatically come on. It doesn't. I've tried swapping the engine cooling fan relay and heater blower relay and still get the same result (Blower works, cooling fan does not).