temp gauge spiking on warmup?

[_dk]

last weekend i had the first bit of maintenance done on my newly-acquired '95 240sx- k&n drop-in, and changed the oil and coolant.

since then, after a cold start, the temp gauge will read cold for the normal amount of time, and then jump to the top of the gauge for maybe 20-40 seconds before settling back down to its normal position.

this worries me. should it?

[Rev_D21]

um if you did a coolant change then u might have an air pocket in the cooling system, this will cause the temp gauge to do all sorts of crazy things.

[drjohn]

Let the engine cool off and open the radiator. On the intake manifold close to #1 intake runner is a zinc colored 10mm head bolt and under it is a copper washer and possibly a sticker still beside it telling you it's a bleeder screw. Remove this screw being careful not to lose the copper washer. Pour coolant in the radiator until no air bubbles come out of the bleeder. Install the screw and rad. cap start and check.

[neil90s13]

I've had the same problem and it was the temp sensor (for the dash)--the connector is riveted to the sensor, and mine now moves freely. I had to kind of bend it over so it would bind and make a better connection

[float_6969]

air pocket or sticking thermostat. Mostly likely it's just an air pocket. Follow drjohn's instrutions and you should be all fixed up. Watch your coolent level for the next couple of weeks as the level may drop due to working all of the air out of the system.