Temperature gauge never moves
 

Hi all,
The temp gauge on my 92 never moves from about 1/3 of the way up from the bottom of the gauge. It is truly stationary from when the key is off to cold start to operating temp. Any thoughts on what I should look at first?
Steve

Probably the engine temperature sensor. It is easy to replace, and is cheap, and they are pretty faulty. It is located on the back side of the engine in front of the driver side. Ill try to find a picture for you.

Don't go jumping the gun and waste your money on something that isn't broken. The temp gauge uses a different sensor than the ECU engine temp sensor. Also even if the gauge sensor is bad, the needle should still return to the bottom when the power is off.

KuoH

Yeah, my gauge never moves at all. Makes me wonder if the problem is with the gauge itself.
Steve

Take a pic if you can. I feel my temp sensor acts kinda weird at times.

Thanks!

i believe if the temp sensor is to blame, then it will be the one on the front of the engine behind the alternator with the one wire connection on top of it. the sensor on the back of the engine is for the ecu i believe. you can also test the sensor to see if it's working. i know someone on here knows how and the values you should be looking for when you test it. good luck.

What happens with mine is when the engine warms up and reaches equilibrium, if I drive on a long downhill section of road, the temp needle just steadily drops down. I know the cooling to my engine will improve, but it shouldn't drop off like that under light engine loads at high speeds (65 mph+).

-Chike

Both temp sensors are right next to each other on the water cross over pipe located beneath the intake manifold. The sensor with two wires is the ECU sensor, the guage sensor has one wire.

http://www.subaruparts.com/diag/?mod...ategory=036A-1


number 21203 and 22630

Dave

I believe you're describing either the knock sensor or the oil pressure sensor.



Dave

How hard is it to replace the gauge sensor (part #22630)? Is it an easy reach with the air pipe and vacuum lines out of the way? I'll probably do this maintenance over the winter...

-Chike

I'm not sure. I know they are easy on the Legacy's:)

It's rare to have a guage fail. I would absolutely replace the sensor first...it retails for about $40 versus about $172 for a new gauge.


Dave

I have replaced both of my sensors, and they are very easy to do. They take about 3 minutes a piece. I will take a picture of the location of my sensors so that you will know what to look for.

Yeah, I was planning on doing the sesnor. My gauge appears to work just fine.

Thanks!

-Chike

Merci! :)

-Chike

Before replacing anything and wasting money unnecessarily, I would try some simple diagnostic steps. Most temperature senders work by reducing resistance as the temperature rises. A very simple check would be to just disconnect the wire at the sensor and see if the gauge goes to cold and stays there. It should not float at any other position. You can optionally ground the wire using 50 ohm resistor, or thereabouts, and watch the gauge. If the needle still doesn't move at all, then the problem is more likely to be in the gauge or the wiring between it and the sender.

You can also test the sensor using a multimeter by grounding the negative lead to the engine and probing the connector, with the wire disconnected ofcourse. The resistance should fall as the engine warms up. You may want to make note of the reading you get at cold, warm and hot to compare with what the service manual says it should be at.

KuoH