Cooling Fan Problem, 91 SC2

I just bought a 91 SC2. The cooling fan stopped working so the guy who had it installed one of those adjustable fan controls. He seems to think the computer is the reason why the fan doesn't work. I would like to fix what ever the problem is, so that the fan works the way it should. Could someone please explain the proper procedure to pin point the faulty componant. I hope I'm not asking too much. Please help.

Thanks, Dennis

Reply to
Dennis
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Your model is an SC, not an SC2. In 1991 & 1992, the coupe only had the dual cam motor (no single cam option existed), and its designation was simply the SC. There were no SC1 and SC2 designations in those years.

You NEED a Haynes or Chilton manual for your car. You can pick up one from any auto parts store for around $10. It will give you troubleshooting procedures and wiring diagrams.

The fan usually only turns on when the temperature indicated on the gauge reaches either 3/4 or the red (can't recall which - do a google groups search of this newsgroup and you'll find a lot of info on the subject). Only then is the fan supposed to come on. Most people think the car is running "way too hot" or "overheating" when they see that level on the gauge and realize the fan is not on and that's an incorrect assumption.

The fan also comes on when you turn on the A/C, but the A/C will only turn on when the outdoor temperature is above a certian point (Haynes or Chilton manual would probably tell you what that is). I've never heard of the PCM going bad in such a way to make the fan control not work correctly. Most often, people report here that it is one of the temperature sensors.

Good luck, Lane [ lane (at) evilplastic.com ]

Reply to
Lane

Thank-you. I have a manual ordered. I've never seen a car that was so hard to identify. The person that I bought it from wasn't even sure what model it was. The title said it was a GL or something I can't remember for sure. So thanks for clearing up the mystery.

Dennis

Reply to
Dennis

There is a good chance that the coolant temperature sensor is the problem. On my car the cooling fan would not come on until the gauge was almost all the way up to the H. I found out in my case the coolant temperature sensor was cracked. Replacing it also improved my gas mileage since the old sensor was telling the computer the engine was cooler than it actually was. The sensor tells the computer what the temp of the coolant is, and the computer decides whether that temperature is hot enough to turn the fan on or not. This is usually

3/4 way up the gauge, in my experience, or with the A/C on, as someone else mentioned.

It is only about $10-$15 to replace. Just make sure if that's it, and if you replace it, that you replace the coolant temperature sensor and NOT the temperature sending unit for the gauge on the dash. They look similar and are located in the same general area on the engine- below the air intake.

Model confusion: the older model Saturns, at least, have no model designation anywhere on the car that I know of. You kind of have to know what you have. In the early 90s, if you had black bumpers and had no reflector between the taillights, you had the single overhead cam, less expensive version, usually designated S_1. If you had body color bumpers and had the reflector between the taillights, you had the dual overhead cam motor and had the more expensive version, designated S_2. If it was a coupe, the more expensive version had hidden headlamps, while the less expensive version had normal headlmps.

I did not know in the early years that the coupe only came in one version.

Actually I think the sedan came in 3 versions for a while- SL1, SL2, but also just "SL". This third option was very basic, I think, and was only available with the single overhead cam motor and was a stick shift.

Reply to
njot

You are correct! :)

Reply to
Steve

I have found it is not safe to rely on the computer to turn on the cooling fan. The computer forgot once and I overheated and broke a hose. Since then I installed a backup thermostat switch from JC Whitney. It is a mechanical type that has a sensor that sticks in the fins of the radiator and you can adjust the temperature of when it switches. I put this switch accross the relay contacts that normally turn on the fan. I little more peace of mind!

Fred

94 SC2
Reply to
Fred V.

Uh, what? I've got a 94 SC2 with 142k on it that I bought new, that has been driven for eleven years in temperatures from -30 to 110 degrees, both on and off the race track. I've never had a problem with cooling when allowing the factory PCM to control the fan like it was designed to do.

I also have a 92 SC which is a dedicated race car which often shows frightening temps on a couple of Autometer oil and coolant temp gauges. I also let the stock computer control its fan and I've never had a problem.

Computer forgot once? I like that, I'm gonna use it at work.

Thermostat, coolant, hose integrity, clamps, fan relay, air dam, and a handful of sensors - there's a lot of stuff other than the PCM that needs to work right to allow the fan to work properly and the allow the cooling system to do its job. I hope you checked all of them prior to installing an add-on thermostat/fan controller. Otherwise that solution may have just covered up a different problem.

Lane [ lane (at) evilplastic.com ]

Reply to
Lane

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