I just recently put a new timing belt on my 91 si and if im driving for say like a hour or so or if iam sitting in traffic i notice my temp. gauge go up a little but then as soon as i start moving it goes back to normal and my car doesnt run any different when it does that...iam not sure if my fan is coming on so im thinking it might just be a bad sensor??? anyone haveany ideas? thanks, Mike

 

It sounds like the fan just isn't coming on. Perhaps something happened to the harness or it came unplugged while you were doing the timing belt? My Neon did exactly that last time I was messing with it. Never ran different would just get hot while idling and return to normal once I got moving (just like you say)...finally after a little wading through the crap under the hood I found that it had come unplugged.

 

ok man i appreciate it i will def. check that out..again thanks

 

hey man sorry to bother you again but i just took it for a ride and the fan does come on...so i mean what else do you think it would be

 

Does it go up really high, or just a little above normal? if its just a little its ok

 

nah it goes up really high sometimes but as soon as i get moving it goes back to normal and the fan does come on...

 

Just on general principle, you should replace the thermostat if you haven't already.

When does the fan come on? Maybe your sensor is turning it on late.

 

my 88 does that too...and has been doing that for a while...make sure your radiator is full...i know i have a leak somewhere but i havnt had time to find it or fix it..but usually when my car is doing the whole up down thing i fill it up with water and it stops doing that...

 

Yeah my next suggestion would be thermostat...since its only a couple bucks. And if you cant get to a store tonight to get one you could pull yours and put it in some boiling water to see if it opens. Idk what else after that...the only other thing that comes to mind would be that actual senson that kicks on the fan. I'd say get it warm or let it warm up and watch the temp gauge listening for when the fan kicks on. It should kick on as soon as it starts to climb above the normal temp.

 

yeah i think iam going to replace the thermostat tonight...thanks for all the help everyone..ill let you guys know what happens...