98 SC2 overheat problem-help

I have 98 SC2 with 117K miles. Recently I have been experiencing overheat
problems and am looking for some advice on the best way to check out the
system. should I check the sensor first or the radiator cap? or the fan
motor? Today when I ran it for about 10 miles around town it quickly got
over 3/4 approaching red, and when I opened up the hood and the fan wasn't
on. I would think it would be on at 3/4 or even 1/2. never had an
overheat, this cars always, always runs on the dot of 1/4 for the life of
the car. Coolant was changed last at 90K. In the 98 is the fan tied to
the A/C? I don't think so but don't know for sure.
Any help would be appreciated.

 

Start car, turn on A/C.

If the radiator fan doesn't turn on, suspect the radiator fan motor.

They're sealed motors, but they have brushes in them. Those brushes wear
out. When they do, you get the symptoms that you describe.

Given the 117K miles, your radiator fan is probably worn out. It's a pretty
easy job to replace it.

 

Kirk,

Thanks. That's where I will start tomorrow. Kragen's stock them. should
be a quick fix look at the manual. Any pointers from anyone that has
changed it already? Things to look out for? Looks simple enough though.

 

I just had an overheating problem on my 93 swi and it turned out to be the
coolant temperature sensor. On my car I could not do the fan test with the
A/C because it is not working, so even if you turn the A/C on the fan did
not work. You can do another quick test to check the fan operation by
shorting out the coolant temp sensor. On my SW1 there are two sensors. One
drives the temperature gauge and the other tell the computer the temperature
of the coolant. The one that drives the temp gauge has one wire and the one
that goes to the PCM has two wires. All you have to do is unplug the
connector of the one with two wires and take a very small paper clip or
staple and connected across the two pins on the plug and then turn the motor
on and the fan should turn on. If it does not turn on it is either the motor
or the relay which turn the motor on. If you have a meter you can go to the
fan motor plug and measure if you have 12V.
Alex

 

They're sealed motors, but they have brushes in them. Those brushes wear

First you should check to see if 12volts are present at the fan motor to
properly diagnose the problem. Anyone can throw parts at a problem, especially
when it isn't your money.

Before starting the car, unplug the fan motor. Have a mult-meter or 12v test
light ready. Start car and turn on A/C. Check for voltage at harness plug. If
present, plug fan back in. If fan does not run, then replace motor.

If no voltage present at either wire, then you need to diagnose a bit deeper.

James

 

James,

thanks. I didn't think about testing the connector first for voltage.
Duh.

I'll do that first.

Jason

 

Even if it does run, you might need to replace the fan motor. At the end of
the brush life, the motors become intermittent - they can start working if
they're bumped or jiggled.

But, it's a good idea to confirm that you're getting 12 volts to the
connector.