Temperature Gauge Issue
 

Took my 2003 WRX on a long drive today and I noticed that when I stopped at traffic lights and junctions, the temperature gauge would move up from half way to about 3/4's. As soon as I started moving, it dropped back to half way.

I could be imagining it also but at times it seemed like it lacked a little boost.

When I got home, I left the engine running and the gauge went up to 3/4 again and the fan was running but the temperature gauge refused to drop down.

Any ideas what it could be and what I should check?

Possibly unrelated, but I thought I would mention it, the car was occasionally as slow coasting speed making what sounded like a trumpet type mouse occasionally. It did however sound like it was coming from the rear of the car so possibly not related.

Thanks for any help.

Today I checked the oil in the dipstick and all is ok. Checked the oil filler cap and no mayo like gunk. Topped the header tank up and also topped up the expansion tank which was low.

Took it for a spin and checked the heaters were hot under normal driving and boost and all was normal. No sweet smell either from the blowers. I then parked up, left the engine running and check the expansion tank. It looked normal with about three air bubbles a second but not frothing or gunk. The fan came on and went off again but the temp gauge stayed at half way which it wasn't doing last night.

I then drove home and left the engine running and again the temp gauge stayed in the middle and the fan also came on and went off again as normal. I then checked the expansion tank and this time the water level had dropped a fair amount. I could still see it but it had certainly dropped down a couple of inches.

Where should the water level in the expansion tank sit normally?

So far, if I do have an issue, it's looking like radiator or hose rather than head gasket unless anyone has any other thoughts???

Both radiator fans should be running to cool down the coolant temperature.

Thank you, just about to drive the car now so will check to see if they both come on.

I have exactly the same issue - except mine temp gauge stays at half way mark and never moves. its going in to Extreme Scoobies on Tues - will let you know what they say. But I have noticed on my Rad there appears to be a very slight leak as I can see coolant stains on the fins near the top rad hose.

Might be worth checking for any obvious leaks and signs of a leak - i.e coolant stains around pipe clamps etc

Are they any signs of water escaping through the expansion hose? I've been told that is a possible HG failure sign

Would also recommend getting a sniff test done too

Thanks, I think a sniff test is worth doing just to be on the safe side. However, I have just done a 200 mile round trip. I stopped after 100 miles and left the engine running and eventually both fans came on. The temperature gauge didn't once move from half way. I checked again after the other 100 miles and again, both fans came on and the temp gauge didn't move from the centre. Now, compare this to Friday, as soon as I stopped at a junction, traffic lights or just in traffic the gauge shot up.

So the only explanation is that maybe the coolant level was just simply low. Topping it up has maybe cured it. I have never needed to do this is 5 years of ownership and 35k miles but I guess it can happen.

The only test left to check the header tank once the car had cooled down to see if the level is still the same.

Will keep an eye on it and keep checking the levels and for any leaks.