94 Saturn SL over heating

I have a 94 Saturn that seems to have a random over heating problems. Out of
the blue the engine just starts to over heat, usually while idling, some
times while driving. It might go weeks and not have a problem then out of
the blue starts to over heat. Is goes from normal which the needle stays in
the 1st 1/4 marking and then jumps to the last 3/4 marking.. The water pump
seems to be fine, it's not leaking any where. The fluid seems to be good and
full. The A/C is always off and the radiator fan seems to run like normal
when it begins to over heat. It over heats for about 5 minutes then goes
down to normal and usually stays there for a couple of days..

Does any one have any suggestions as to what the problem might be? I am
planning on changing the thermostat and flushing the radiator to see if that
solves the problem..

Thanks..

 

Cooling fan motor. When they fail, they start by failing intermittently.

The brushes wear out and start not making contact. When you start moving, it
spins the fan, which can cause the brush to start making contact.

Replace it and you'll be much better off.

 

I have noticed that is over heats while on the highway some times also??

Thanks for the reply..

 

First of all, I want to say what I say to everyone (again and again) posting
a similar situation to your own.

In the old days, overheating meant that the pressure relief valve on the
cooling system cap popped, or hoses ruptured, and you were blowing steam.
THIS is overheating.

Your car probably isn't "overheating". Normal operating range on the gauge
is half to 3/4. On hot days in slow traffic (or stopped/idling), my 94
SC2's needle will sometimes go above 3/4 and close to the red. I don't
worry - eventually, the fan comes on when it's designed to and reduces the
temp. If it never comes on, then there is a problem there.

First thing I would check is whether the airdam is still there. If that
breaks off (which is easy to do), the engine will not cool as designed. To
see if your fan motor is in working order, turn on your air conditioning and
it should run. Others have also left good advice and mentioned things to
check in this thread. You can also use google groups to do a search of past
posts on this newsgroup and you will find that this has been discussed a lot
in the past.

FYI - I've run my 92 SC race car on the track for 20 minutes, very close to
redline much of that time, on a 95 degree day. Due to my own actions (I had
removed the airdam temporarily), my temp gauge was at the top of the red and
nearly pegged the whole time - even with the fan on. A cooldown lap was all
it took to bring it back down to 1/2. I didn't worry about it because these
engines are pretty durable when it comes to temperature. It's just the
owners who aren't.

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

 

I'd suspect the thermostat may be intermittenly sticking..

 

I have a 94 sc2 that i bought used. It's definitely overheating. When
my needle reaches close to the red...it smells hot and performance is
effected. I have to blast the heater to lower the temp.

 

The first thing I'd check is the coolant temp sensor (about $15). It
provides a signal to turn on the cooling fan.

And it's located upper right of your engine block as you stand looking at
the engine...under the air snorkel. There are two sensors there...they look
like little spark plugs. One sensor has one wire...and that goes to your
temperature gauge.

The other has 2 wires. That's the one you're looking for. You'll lose a
*little* coolant when you remove the sensor...so be careful no to burn
yourself.

You'll need a deep socket 13 mm, I believe...and don't over tighten it.
It's an easy fix, if that's the problem.

In the mean time, hit the A/C button, just long enough to get the compressor
running, then shut it off. If the fan motor is working, the fan will come
on as part of the cooling system, and shut off when the engine reaches
normal operating temps.

I controlled the temp of my engine for almost a year this way before
replacing my coolant temp sensor.

Good luck.