Brewski4u1

iTrader: (2)

ok i drive about 45 min to a from school everyday and most of it is on the highway. but while i'm driving on the highway i have been noticing that my temp gauge is jumping all over the place, it usally stays right under 210 but its going all the way up to like 240 and a little above and then the next min its right back down. does anybody have any idea what could be causing this?? and help would be great. maybe this has some thing to do but who knows, the car has about 61000 miles. w/ the stock water pump. could the water pump be dying? just an idea

C4VetteLS1

check the water level of course...your thermostat could be sticking

whitez71

Maybe the gauge is screwed up. I would take a reading with a scan tool and see what is going on.

Constrictor 98TA

As the other guys have said, its either a faulty gauge/temp sender (doubtful), bad thermostat (very possible), or air in the coolant system (somewhat possible).

If its air in the system, its easy to bleed, just let the car run with the radiator cap off til it gets to 210 degrees, then turn the car off, and top off the radiator until it doesnt allow any more fluid to go in.

If its the thermostat, its very easy to replace. Right on front of the water pump, just remove the two hoses going to it, and the thermostat is held on by I think 3 10mm bolts, just pull it off and replace it.

If its the temp sender, thats easy to replace too, just use a 19mm deep socket and pull it off the cylinder head. It is located on the very front of the side of the drivers side head, right above the spark plug for the number 1 cylinder. Unscrew this one and put in a new one.

If its your gauge, I cant help ya there!

Screamin_Z

iTrader: (2)

Mark at Raging Motorsports told me that the gauges in our cars SUCK!!! when I got my computer reprogramed I also had a 160 degree thermo put in plus fans reprogramed he said don't really pay attention to that POS, it isn't accurate at all. If u want an accurate reading ur going to have to install a new gauge like autometer or something.

jimmyblue

iTrader: (11)

The gauge may suck, but it should suck consistently.
If it moves there's either a thermal or electrical
reason. Fast movement can't be thermal. But since
it's an idiot light made to look like a gauge it's
possible that true engine temp is fluctuating about
either side of the "look scary" threshold. Must get
true readings via the ALDL port, maybe a buddy with
Predator or AutoTAP/EFI-Live etc. but something.

Some kind of wiring / fan defect like a dead low-speed
fan could really let you yo-yo, only coming down when
you hit the high speed fan on threshold temp and then
having no cooling when you pass the high speed off temp
threshold. Don't remember where these lie. But low
speed cracks on at 210F and high speed has to be above
that.