Alright: 97 Impreza, 2.2ltr, manual tranny.............

 

so I have been encountering what i felt was an overheating problem.

 

however: i have eliminated the t-stat, radiator, coolant levels/quantity/quality. waterpump is also appearing to function just fine.

Radiator Fans turn on when they need too.

 

So this is what is happening: I turn the key when my car is dead cold(without turning car on) The temp gauge shoots straight to the top H.

 

Then I make the car run, same thing happens. If it is doing this when it is cold: it is not a over heating issue.

 

I replaced the Coolant Temp Sensor: That did not fix this problem.

 

Any ideas guys?

Also: CEL is not on.

I'm not certain, but your engine may have two coolant temp sensors. Some years had one temp sensor for the ECU, and another one for the temp gauge in the dash. If you have two, which one did you replace?

 

Also, a loose, dirty, or corroded, connection at the coolant sensor itself can cause the problem you described.

Well it sounds like you know what is not causing the problem now! From what you have written, this is sounding like an electric issue. Grab those schematics and find the coolant temp circuit in.....engine electrical I think. At least that is where it is for the 04. I would trace the circuit in the car from the meter assembly to the sensor. Probably a short to ground. The temp sensor is a variable resistor so you could get a reading off your old one or disconnect and measure the new one then work through the circuit to see if the meter is getting the same reading you got at the sensor. Also I think the ECU monitors this circuit, again it does on mine but you'll have to check your diagrams. If so, you should unplug that connector from the ECU so don't get funny readings.

 

Good luck. I finally ran down my electrical gremlin in the meter assembly PCB. I suspect though that is rare and an abraided / rodent chewed wire is usually the culprit.

dude: yeah i think i got two. i replaced the one that sends the info to the gauge...not ecu.

 

if it was the one the ecu needs: i dont think my fans would be working the way they always have...could be wrong though.

 

redimpreza: im thinking your hitting on something with a ground somewhere.

 

hoping someone else has seen this: ive googled the ************ out of it, cant find anything.

 

all in all: im not too worried: what i may do is just throw a VDO temp gauge(from an older vw scirocco) on my dash...bypass that damn circuit all together.

There are some screws in the back of the instrument cluster that I've heard can loosen up and cause issues with the speedometer mostly. Don't know that any of those would cause problems with the temp gauge, but it could be worth looking into.

 

 

The sensor you replaced had one wire right? That's the one that works the gauge. Just make sure the wire connector fits snugly on the tab on the sensor. Did you check the wire where it meets the connector? Made sure it's not frayed or corroded?

 

That wiring runs over to one of the three plugs on the bell housing on the passenger side. Those have been known to get corroded inside the connectors. Lots of times unplugging and reconnecting those will fix sensor issues.

from the subies ive worked on, there are usually 3 sensors/switches for the cooling system. the coolant temp SENSOR is for the ECU (and located near the theromstat housing), the radiator fan SWITCH is for the fans (and is located in the radiator), and the coolant temp sending unit or SWITCH is for the guage (and is usually located on the intake or coolant pipe somewhere).

 

this is the set up on my xt6s, and IIRC the same way my OB wagon was also. however the wagon is long gone... the one for the guage on the xt6's is under the intake on a "coolant pipe" towards the back of the motor, and is a M-Fer to get to it.

Edited August 2, 201114 yr by themoneypit

 

 

The sensor you replaced had one wire right? That's the one that works the gauge. Just make sure the wire connector fits snugly on the tab on the sensor. Did you check the wire where it meets the connector? Made sure it's not frayed or corroded?

 

DOH!

I suck sometimes. I replaced the ECU one. The 30 dollar one. Suck. The one your discussing is pretty much next to the ECU one....has one wire plugged into it...

im going to get on this tomorrow...will post back when i learn more info..

 

Thanks fairtax

Happens all the time. Hopefully that will fix it and you will no longer feel the need to cut up your dash to put in some tacky aftermarket add-on gauge.

 

(Don't get me wrong, VDO is one of if not the best manufacturer of automotive gauges. That doesn't mean you need one stuck in the corner of your dash.)

haha

just went out, unplugged the single wire sensor.....and well: gauge didnt shoot up. plugged it back in: gauge shot up.

 

 

ordered new sensor from rockauto. should have it in a few days.

 

thanks again, im betting dollars to donuts this takes care of the problem.