my temp gauge goes directly to overheat when i start up my car. the car isn't overheating, the gauge is just whacked. i replaced it w/another gauge from another cluster. same result.

anyone know what might be causing this and can answer in simple terms for the electronically impaired?

thanks!

I would say your problem lies with the temp sensor, not the gauge.

EDIT: Here is what Haynes says: There is usually a coolant temp sending unit mounted on the t-stat housing. If an overheating indcation occurs, check coolant level, and wiring between gauge and sending unit, and make sure fuses are intact. Test circuit by grounding the wire connected to the sending unit while the ignition is on (Engine not running). Caution: Do not ground the wire for more than 2 seconds! If gauge deflects full scale, replace sending unit. If gauge does not respoond or does not indicate on overheating condition, the gauge wiring is faulty. If you do in install a new one, use sealant for the threads.

Hope this helps,

JB

thanks, i'll give it a try

do a temp sensor swap, a temperature sensor sender (it has one white and brown [i believe] wire to it) and check a different, known good cluster. there is a nicad battery or two in there that go bad and make the gagues go wonkey.

if all else fails run a ground from your neg terminal to your intake manifold with a two foot premade cable, probably available from pep boys. the batt is only grounded through one wire, which is silly to me. another ground can only help. Hell, it fixed my problem.

watch temps in the future, m30's are great fucking motors (I love mine) and will run for 400,000 miles easy, but there is a saying that the only way to kill an m30 is to cook it. that's true, one good overheat and it wont run the same (warped head, bent valves, etc.).

its likely to be a short somewhere between the sensor and the guage. I had a similar issue and it was right at the sensor where the spade terminals were damaged.