Hi guys,

I have a 2006 Impreza sti spec d. Had it a few months now and everything is fine. Up until last Thursday I was driving to work and noticed the temp gauge had climbing to the top of the middle section so I pulled over and turned the car off to let it cool down abit before going into work. The drive home, to and for work on Friday and today were fine. Then I went to the shops and on the way home the same thing happened again. So I let it cool and got it home.

The car was serviced recently but the coolant wasn't changed only the oil and filters etc.

I've read a lot of different things people saying it could be a sticky thermostat or the head gasket.

Is there any way I can tell which one is easily?

I've checked the oil both the cap and the dipstick and fine and clean. It's brand new oil and doesn't look like it's been mixing with coolant.

The coolant is a dirty black colour but again doesn't look to have oil in it.

What else can I check before I replace the thermostat and coolant?

 

Id start off with a coolant change, maybe a flush through. Dont think of the dreaded head gaskets yet as it might be a case of good,clean fluid . If theres any doubt on the thermostat, then id change that while the systems empty and theyre cheap enough . When you fill up, try and fill via the coolant feed to the turbo as its got less chance to airlck that way.Then go from there.

 

first port of call, check cooling system is bled properly then get a sniff test done to check for hg failure

 

Thanks for the replies guys. I'm hoping it's not the head gasket. I'll try the coolant and thermostat tonight after work.

What kind of coolant does the car take? Do I need to get it from Subaru or can I get it out of halfords or somewhere?

 

Does it loose any coolant when you drive off boost or after being driven on boost.

 

No it doesnt use any coolant. I topped the system up after the first time it overheated and checked it this morning and it was at the same level

 

Coolant from a decent motor factors, ask for stuff suitable for an ally engine and with corrosion inhibitors.

Mix to 50%, system takes abt 7 ltres.

 

Is a sniff test done by removing some of the coolant from the tank next to the manifold or will the one on the front next to the radiator do?

Cheers