I have a STI3 Wagon.
Just done Trax this weekend and after the first session the temp needle went through the roof - hit the very top of the gauge.
Car was still fine - all the fans working etc.
Let it cool off and everthing seemed to be ok. Did the second session and the we were stopped half way thought and again the needle went to Hot.
As soon as we started the needle went down agin,
On the way home the needle would go from normal to Red line hot in 2 seconds and then back down again.
Any ideas?>?
Again the engine did not seem especailly hot.
It had not done anything like this before the track day.
Thanks
Michael

 

MMmmm

You say the engine does not seem overly hot, this could meant the the thermostat is stuck or only opening a small way, if this is not the case it may be the sender unit has gone mad.

 

If the needle's moving that quickly right to the max, I think it's likely there is an intermittent short in the sender or wire to ground. Coolant temperature just cant change that quickly.

Rich

 

Yosser
It may be the voltage stabiliser for the dash board have it checked.
Jack C

 

Thanks folks
Took it down to Scooby this weekend - couldn't find anything wrong.
It's going in for it's 30,000 servce so I'll watch it till then and see what happens.
Fans are coming on at the right tem etc so it all looks ok !
Cheers
Michael

 

Yosser. You sound like you need a new sender unit. It happened to my WRX a few months ago. Tried changing collant e.t.c. then was told by subaru dealershioe thermostat was gone. It needed a new sender unit..I dont think it was that expensive

Hope this helps.

Ronaldo