97 SL2 radiator cooling fan problem

The radiator cooling fan runs and keeps engine cool when the air
conditioning A/C switch is turned on, but will not run and engine overheats
when air conditioning A/C switch is turned off. I understand that the fan is
supposed to run constantly when A/C compressor is engaged to move air
through the condenser core. Any suggestions as to why the cooling fan will
not run while A/C switched off.

 

Define 'overheats'.

How high does the needle go on the temp gauge?

Lane [ l a n e @ p a i r . c o m ]

 

Your fan is not getting the signal to turn on. The signal comes from your
coolant temperature sensor. Your car is 7 years old and this might need
replacing.

Unless you flush your radiator anually, it's not uncommon for this thing to
fail. I'm pretty careful with my car and mine has failed finally at 10
years / 156,000 miles. Saturn wants about $140 to change it.

The coolant temp sensor costs between $15 and $20. The thermostat costs
about $30-35.

There's a difference between the thermostat, which regulates flow of coolant
to the engine, and the coolant temp sensor.

The temp sensor is what sends the signal to your fan to turn on and off.

Chilton's manual shows how to replace the thermostat. Not sure about the
sensor.

Barry

 

I recently have a problem on my SL2 1993. The fan start only when the temp
reach the red zone on my gage. I changed my TCS ( Temperature coolant
sensor ) and now he work fine.

This sensor send the temperature to the PCM ( computer ) and an output on
the PCM unit start the fan.

Claude

 

....with Dexcool you don't flush yearly (typically).

 

No, GM says you don't have to because the EPA wants them to say that. I
sure as hell wouldn't trust that dexcool stuff, given the troubles
they've had with it....

 

....yeah, I remember a while back on a coolant thread one guy mentioned
getting the Dexcool out of his vehicles and using vanilla ethylene glycol
and flushing regularly.