Hi, having overheating problem.

[Theophilus]

Hello,

I searched but didn't find a clear solution for my problem.

I have a 2001 4 cyl. a/c, auto PT w/64k on it. The fan operates automatically at about the mid point on the temp gauge, and comes on immediately on a/c. I cannot hear or feel any difference in sound or air flow. I replaced the thermostat, cap and did musical chairs with a high/low fan relay with no change.

Here are the symptoms. Temp gauge stays mid point for 30 minutes or so no matter the conditions, driving, in park, in drive w/foot on brake, a/c on or off. In another 5 to ten minutes the temp climbs slowly until it boils over. The only thing that may be odd that I noticed is the fan doesn't come on with the key in the on position w/the engine not running when it is hot.

I hope I've stated this clearly.

Can someone help me?

Thanks,

Joe

[Taggert_LOA]

sounds like your rad cap isn't holding the pressure. i'd replace it.

[bobs turbo pt]

i agree with taggert

[Theophilus]

Thanks for the replies. Yes the cap is new, and the system has and holds pressure. I'll edit the post to reflect this.

[CREWZIN]

Welcome to the forum.
The fan comes on at mid point but when the engine is cold (when you first start up in the morning) and you turn on the AC, does the fan immediately come on? It should. If not, one of the speeds (2 speed fan) is burnt out. If it does, the only other suggestion is that you might have air in the system and it needs to be bled of any excess air. The bleed valve is located under the radiator cap.

[Theophilus]

Thanks for the reply and the welcome. Glad to have found this place.

So I double checked bleeding and that the fan operated on a/c when the engine was cold. Sure enough the fan isn't working on a/c when cold though I was certain I had checked it. It is the fan motor that is defective then, isn't it?

[CREWZIN]

YES!

Want to check it for sure? The pic below show the electrical connection for the fan motor. Slide the red tab to the right and disconnect the wiring. Take a hot and ground wire to the wires connected to the motor and the fan should run on high speed.



You can do it yourself. Fan and housing comes out from the top. Top hose of radiator, section member where hood latch is all have to come out or loose. Radiator has to slant forward to give enough room for the fan housing to come up and out. About 6 bolts on the fan housing hold it in.

[Theophilus]

Thanks, I'll check it out to be certain. Storms here right now and no garage so I'll probably have to do it tomorrow.

Should I replace the whole assembly or just the motor? About $60 difference.

[CREWZIN]

I couldn't find just the motor. Of course that was about 5 or 6 years ago so maybe now someone's come out with just the motor because of all the failures. If you can, sure save some money and just get the motor.

You might be able to replace it without taking out the whole housing too. Not sure of that.

[Theophilus]

Well it took me around 2 hours to complete the r and r of the fan. It went ok. No major hang ups.

Thing is, it did not solve the problem. Fan came on sooner and sounded faster/louder. Still overheating though after around 40 minutes or so with or without the a/c on. Seems it took longer with the a/c off but I would expect that with more load. With the a/c off, running the heater full speed kept the car at the mid point on the gauge.

Called the local big name heat, a/c and rad shop to see about them taking a look. Decided against it when the guy told me it could be the head gasket ($1300+) but the only way to tell was to do a 'sniff test'. Something about gas smell near the firewall. LOL! Heard of this? It is showing no sign of a blown gasket, holds preasure, no bubbles in coolant, no steam, nothing.

I think it is going to be the PCM, but I'm going to let my BIL check it out at the shop he works at tommorrow. Have any suggestions during the mean time?

Thanks again for all the help.