Problem with my car running hot and temp gauge jumping around...

[Joey Link]

Tonight on the way home from the meet I noticed my car was running a little hot, right on the first mark (I guess that means 1/4th?). Normally it runs about two needle-widths below that. As I got on the freeway I noticed it went up to the half mark, then fell back down quickly, then slowly rose back up. When I parked I could see the needle jumping maybe every few seconds very quickly, but only a few needle-widths. Not sure what this is, is my temp sensor going out? Thermostat probably isn't the culprit, but I'm not sure. Anyone experienced this before?

[KenC]

You probably need to replace you SI batteries on your cluster board. However, I would try tightening the grounding nut on the back of the temp gauge first.

[e30frosh]

My thoughts exactly, the ground nut was loose on my 90 325i. Solved the happy needle quickly.

[StereoInstaller1]

Joey, I would take the SI board out...I bet yours is the kind without batteries. Either way, it would be good to know if a maintenance issue is there, waiting.

I have had my batteries and battery holder waiting to go in for nearly as long as I have had my car.

Luke

[Digitalwave]

Your car normally runs BELOW the first 1/4 mark? That is too low... it should at least be between the 1/4 and 1/2 mark once its heated up. Your thermostat might be broken open.

[Joey Link]

Yeah normally runs below. Maybe I should replace the thermostat?

[KenC]

Yeah normally runs below. Maybe I should replace the thermostat?

I'd inspect it. It might also be the coolant temp sensor.

I'd definitely take your gauges out and tighten the grounding nut on the back of the temp one though.

[Digitalwave]

Yeah normally runs below. Maybe I should replace the thermostat?

Even if its not broken I would, and replace it with a higher temp thermostat because its not good for your car to run that cold.

[Jordan]

Even if its not broken I would, and replace it with a higher temp thermostat because its not good for your car to run that cold.

Water temperature, and oil temperature are 2 totally different things TEEJ.

Cooler the water the better. Wicks more heat off the head and helps the engine make its optimum power.

[Digitalwave]

Water temperature, and oil temperature are 2 totally different things TEEJ.

Cooler the water the better. Wicks more heat off the head and helps the engine make its optimum power.

I know they are different, but you are saying its good that his car's water temp is always below the 1/4 line?

[hamann318is]

I know they are different, but you are saying its good that his car's water temp is always below the 1/4 line?

There is a reason there is a thermostat. If BMW wanted cold motors, why even bother throwing one in there?

[StereoInstaller1]

because people want a heater?
LF

[SebSter]

My car has been running like this for 3 years. Changed the thermostat and no help, still stays near the 1/4 or just above it. The heater only heats at FULL red position, otherwise just cold air blows in (in the winter that is).

[Jordan]

because people want a heater?

Ding ding ding.

[E30 Wagen]

I'd inspect it. It might also be the coolant temp sensor.

I'd definitely take your gauges out and tighten the grounding nut on the back of the temp one though.

where is this grounding nut you speak of? It seems mine might need to be tightened as well.