Over heating 2.5L STI 2007 Hawk
 

Hi everyone this is my first post here, I have recently bought my first Subaru 6 months ago after always wanting one, it is a 2007 Impreza Sti completely standard with blitz catback exhaust and 94,000 miles on it.

When I bought it it wanted a new clutch so I have replaced this but recently it started to overheat on the way back from Sheffield one day so I replaced the water pump thermostat timing belt and tensioners etc.

The water pump was quite tight so expected this was the problem and it seemed fine for a week or so but now has started to over heat again. I have also noticed a slight misfire under acceleration and on cold start up for the first few seconds of idling. The oil is not contaminated as I have just changed it and neither is the coolant however it throws water into the overflow bottle and then overheats. It is fine as long as I keep topping up the header tank but only lasts around 5 miles before needing topping up and overflow emptying again.

I'm now assuming the head gasket may be at fault as I can see a little bubbling in the header tank but I don't want to go through a costly engine rebuild if not necessary so wanted to see what you guys thought? I have taken it to my local garage who I trust with all my previous cars but they won't touch it.

The bottom end of engine was rebuilt once before approx 40,000 miles ago for failed pistons which I have receipts for so the head gaskets were replaced then but doesn't say the heads were skimmed do may not have been

Is there anything I have missed before taking to a specialist at more expense?

I am considering doing the job myself as I have experience rebuilding engines as I am stock car driver although have never done one if these, has anyone ever tried this before? Is it do able from home?

Thanks in advance for any help.

Kyle

Yep headgaskets
Take the over flow pipe from the overflow & attach it under your wiper blade , take it for a spin & watch the water piss out as you hit boost ( as the heads are lifting under pressure,
Failing that you have ringland failure , poss a combination of both
You have replaced the thermo & water pump so 99% it’s the above