Temp gauge readings

How high can the temprature gauge go without the car over heating?
I have a 93 SC2, and usually run the A/C when I see the temperature gauge
get a little more than half way on the gauge, just to turn the cooling fan
on just to bring the temperature down. This happens when I'm stuck in
traffic.

If I don't do this, the guage keeps climbing. Today I just let it get
about just before the red area, then switched the A/C to cool the car
down.

When should the fan come on without me needing to turn on the A/C? I'm
afraid if I just let the temperature climb without doing anything, the fan
will never switch on.

 

There are 2 sensors on this car. One for the gauge, and another for control.
The control feed the PCM to control both rad fan and fuel injector pulse
width based on coolant temp. It seems that is not that uncommon for the
control sensor to go bad. Even though your gage goes up, it is possible the
PCM always sees a cool engine temp.

 

This has been discussed at length here in the past. You can find it all in
Google groups:

http://www.google.com/groups?as_q=temperature gauge red&as_ugroup=*saturn*

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

 

It's perfectly normal for the engine temp to get a hiar abouve the three
quarter mark. At that point, the cooling fan kicks in until the temp is back
down around the quarter mark.
Your engine is going to heat up in traffic because there's no air hitting your
radiator, cooling it down.
If the cooling fan does NOT kick in when it starts to tip towards the very edge
of the red, I'd suggest getting the cooling fan relay checked - it might be bad
if you have to turn the fan on maually.

 

My 97's gage was like that when new, and then when a temp sensor was
replaced the point where the fan kicks in is at the halfway mark. Whether
it was the sensor alone or a PCM flash (updated EPROM programming) I don't
remember.

 

Guys,

The radiator fan motor is a DC motor that uses brushes. It is a wear item!
It's also a sealed motor (no brush replacement caps) so you have to simply
replace the whole motor when it dies. While the relay can also wear out,
this is far less common than fan motors wearing out.

So, if your temperature is going too high, check to see if the fan is
working.

If the fan is not working, suspect the fan motor first.

 

Had same problem. It's not supposed to go to 3/4ths then have the fan kick
on. Mine kicks on just beyond half after I fixed it. Service manager
confirms that sensors get green corrosion on them (I think it's brass or
copper,) and the line to the fan corroded as well. This stops it from
kicking on because the corrosion causes it to short. Bought a new line and
sensor and all is well.
Joe