93 xlt heats/cools rapidly??

[Skohler]

I have a 93 xlt with 108k miles. I have noticed recently that the guage for engine temp starts low, goes up to the "o" in "normal" and back down low alternating back and forth as I am driving. This did not happen for the first many years I have drivin it, no matter what the outside temp was, it always hung out to the left of the "n". I know it is getting cold, but it has been doing this for a while now. Does this sound like a thermostat that is stuck open?? I replaced the thermostat once around 60K. Just want to make sure that it isn't something else.

Thanks
Steve

 

[Skohler]

Anyone???

 

[Diff Whack Daddy]

Depending on the outside temperature, this is normal. With a 198 degree thermostat it will actually go all the way up to hot and then when the thermostat opens it will drop back down. With my 180 degree thermostat, it goes up to about half way and then drops back down.

 

[jeffdoerr]

My 94 STX does the same thing. I got 110k on it, it heats up fairly quick, then drops normal for a few miles, then back to the heat gauge roller coaster.

 

[Skohler]

Thanks, I guess this is normal. I still seems odd for the temp to vary that much (back and forth) over the course of a few miles, it is always good to find someone else with the same thing.

Thanks again
Steve

 

[Diff Whack Daddy]

As long as it levels out in the normal range you are okay.

 

[TPLYNCH]

Try replacing your radiator cap. If the spring is bad it doesn't hold at the proper pressure. When your coolant gets to a certain temp/pressure, the cap releases and your temp drops, running this cycle over and over. If if keeps doing it, then the T-stat is probably the culprit.