Fan cuts on randomly
Thread Starter
Racer
Joined: Mar 2002
Posts: 312
Likes: 6
From: Troy Al
Fan cuts on randomly
Hi. My 93 coupe has a situation where the cooling fan cuts on randomly, and sometimes not when it's supposed to. I have been reading up, mostly older posts here, that the PCM controls it. That and the temp sensor. I would assume that's the one on the front of the engine. Digital meter reads normal, but is often hard to see. I turn on the parking lights for a brighter view. It comes on at first start up when the engine is cold, and sometimes when driving it does not come on. Has anyone else experienced that?
Melting Slicks
Joined: May 2013
Posts: 2,692
Likes: 349
From: Sacramento California
Hi. My 93 coupe has a situation where the cooling fan cuts on randomly, and sometimes not when it's supposed to. I have been reading up, mostly older posts here, that the PCM controls it. That and the temp sensor. I would assume that's the one on the front of the engine. Digital meter reads normal, but is often hard to see. I turn on the parking lights for a brighter view. It comes on at first start up when the engine is cold, and sometimes when driving it does not come on. Has anyone else experienced that?
It's not supposed to come on simply because you are driving.
Thread Starter
Racer
Joined: Mar 2002
Posts: 312
Likes: 6
From: Troy Al
It comes on at first start up. This is to say when the engine is cold. It did not come on when I was going down the highway on a hot day. 95 degrees out. The car was heating to like upper 220-230. pretty hot. I was able to limp home by running the AC, thus moving some air over the radiator and avoiding stops as much as possible, so the airflow keeps it cool.
Melting Slicks
Joined: May 2013
Posts: 2,692
Likes: 349
From: Sacramento California
If you haven't already, read this thread full of helpful cooling information on these cars: Corvettes, Summer, and High Coolant Temperatures
This seems strange. My 1995 LT1 does not run the fans at cold start.
In stock form, the fans don't come on at speeds above 35 MPH because at this speed the airflow across radiators is as good as the fans could do by themselves. This speed restriction is programmed into the computer, IIRC. Also, in stock form the fans don't come on until the digital gauge hits 228F, this is normal. Yes you can turn on AC to force the fans on, I do this sometimes to ease pressure on the system in ongoing slow traffic. But I don't think the fans will come on above 35 even if the AC is on (I could be wrong), this *may* address your concern about the fans not coming on at highway speeds.
If your car is running above 220F at highway speeds, you have other issues. The cooling thread linked above has many suggestions including cleaning debris from the radiator / condenser area. I mounted a couple layers of mesh screen ("hardware cloth") over the air intake to keep future debris out of the radiator, works awesome.
Hope this helps you
This seems strange. My 1995 LT1 does not run the fans at cold start.
It did not come on when I was going down the highway on a hot day. 95 degrees out. The car was heating to like upper 220-230. pretty hot. I was able to limp home by running the AC, thus moving some air over the radiator and avoiding stops as much as possible, so the airflow keeps it cool.
If your car is running above 220F at highway speeds, you have other issues. The cooling thread linked above has many suggestions including cleaning debris from the radiator / condenser area. I mounted a couple layers of mesh screen ("hardware cloth") over the air intake to keep future debris out of the radiator, works awesome.
Hope this helps you
Last edited by DGXR; Sep 15, 2020 at 03:04 PM.
