Help with temp gauge moving up and down

[gandi240sx]

Ijust picked up a 1993 240. The car is all stock but the needle for the temperature when warm goes from normal to almost high when driving, up and down, then stays normal for 30milesthen back up for 2 miles then back and forth. But it doesn't stay in one area all the time but mostly in the normal range. The guy stated that it has always done this. He had a newwater pumpand thermostat put in about a year ago but the needle did this before this. There are no lights that go on when it does this and the car runs great. No smoking or weird things going on. I noticed the heat is luke warm but not hot like it should be. Please respond with any help? Is it the temperature sensor and where could I get one and where is it located?

[480sx]

First, make sure your radiator is full of fluid.

Could be a CLT sensor going out.

It could also be a bad engine ground.

[chrismo240sx]

wtf? i just started having the same problems with mine...93 hatch, im afraid to let it go too high tho so i shut the car off and wait a minute or two

i checked my fluids and im good, never changed the water pump or thermostat but if ur saying u did, it might not work for me either.

how do u check ground wires? newb q!

[Bakani]

I had the same thing happen to me last month. I suggest a quick thing whitch solved mine get some radiator flush and use it on yer car only about 6 bucks at an automotive shop. It might be as easy as something clogged in the system.