1993 SL2, 156K miles I have had this car since new, normal driving temp gauge always has read at the 11 oclock position( 10 oclock being cold and 2 oclock being redline) Just recently, when stoped at idle in traffic, fan not running, gauge would move up to near redline (2 oclock). Took it to dealer, installed new fan motor. Still did the same think except fan comes on when gauge reaches 1 oclock position. Took it back to dealer, they hooked engine up to computer, said fan comes on when coolant temp reaches 225 degrees (seems too high to me) and then cools down to 180 degrees. They say this is normal and my temp gauge is inaccurate. In the 16 years I've owned this car, the temp gauge has never gone past the 12 oclock postion. At hwy speeds, temp gauge reads 11 oclock. Had coolant temp sensor replaced 2 years ago. Fan runs when a/c is on and gauge reads normal (11 oclock). Ideas anyone? Thanks.

 

When was the last time you had your cooling system cleaned and flushed?

 

so is the 11 position where the 1st line is over cold (checking to see if I understand your positions right)? have you replaced the thermostat at all? 225 is when the fan is supposed to kick on and drop it to a little less then the 1/2 mark (12 position). it could be your gauge is off but you also have a sensor above the ects that tells the gauge what the temp is (single wire pretty much straight up from ects and kinda looks like the ects) maybe go to the dealer and ask for that sensor and see if that makes any difference.

I can't say I've seen my temp gauge budge when on the freeway unless its already above 1/2 from idling or moving slow in traffic first. the fan is supposed to kick on when the a/c is on so thats normal

 

indeed -- 93's had two separate temp sensors -- one (ECTS) for the PCM and a second single wire device for the dash gauge.....

 

Thanks for everyone's comments. Had cooling system flushed, thermostat replaced, coolant temp. sensor replaced 2 years ago(about 20k miles ago). 11 oclock position is first mark above cold. That's where it has stayed always and where it stays now when at cruise speed. Only creeps up when stopped for a few minutes at idle. If Saturn dealer hooked it up and says fan comes on at 225 and is supposed to do that, although dash indicator is at 1 oclock (1 mark before redline) then everything must be OK. Perhaps gauge is bad after all. Just never seen it do this previously.

 

I'd say before condeming the gauge for sure try replacing the sensor that tells the gauge where it should be then if it still does it....