Hey Guys,

I'm finding that when I give my car a good flogging. The coolant pushes into the overflow bottle. Im not game enough to push it any further as Im sure it will burst out of the over flow bottle. I orginally thought it was a head gasket but she doenst over heat at all. She runs really well. Although what bothers me is how the coolant doesnt return back out of the overflow bottle. It seems to just sit in the over flow bottle.

A bit of background on my car. She's running a full 3 inch exhaust and been been tuned. How much power. I have no idea. What I suspect has happened. While it has been tuned by the previous owner. The car has had too much boost put though it and has stretched the head bolts causing head lift. Am I on the money or should I be looking at something else?

Can someone tell me if theyve had a similar issue with their MY06 STi and what was the fix?

Cheers

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MY06 STi

Yes it could be leaking headgasket on boost. Try the simple things first try a new radiator cap make sure it's the right pressure cap for your car being a STI they had a higher pressure cap on originally. That was my prob had same symptoms as yours had the wrong type of cap on because I was running more boost. S technic pick this up on mine and make sure you have a genuine thermostat in. Doug did a tk headgasket test on mine and it was fine put new gen thermostat and uprated cap and has been fine since. Hope yours is as easily fixed.

Mark

Mine had this was hg hopefully not the same case :s .....rj just had a hg fail in similar model too

using the Perth-WRX mobile app

it doesn't have to overheat to be a leaking headgasket issue. the ej257's are prone to head gasket leaks that only show up under sustained boost conditions. take it to stechnic for a tk test after it's been flogged, that's the only way to know for sure. good luck.

Hey Mark,

I've put a new STi cap on the filler bottle aswell as replaced the one on the radiator. Both genuine parts.
I guess my next thing I try is installing a new thermostat. The only thing is I'm not feeling too confident with this as the paperwork for the car shows that MMS replaced the thermostat in a major service done back in early 2014. I highly doubt the thermostat has failed in that time... But I'll give it a go anyway! Fingers crossed!!! I soo do not want to rip this engine out!



Cheers, Steve

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MY06 STi

Sounds like the go dnbosiri...

Btw what kind of cash am I looking at to fix this if it's a boost leak? I was thinking if I have to rip the engine out I may aswell throw in a brand new short motor. Rising Suns prices are pretty good!

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MY06 STi

unfortunately it doesnt matter how big or small the leak, if its the headgasket then it's engine out. you'll pay a workshop in the $3k-$5k range for all parts and labour depending on how much extra work you do while the engine is out (i.e. clutch, timing belt, etc).

unless you take the engine out yourself, which is an excellent learning experience if you have the time.

btw not trying to scare you, best thing you can do is get the TK test done before you make any assumptions. there's a chance (albeit a small one IMHO) it's something small like the radiator cap.

It's all good. I'm not too worried. I'll get the TK test done. If sh'es Fubar I will wack in another short motor while Im at it. I'll most likely pull the engine out with a couple of friends. So Im sure the learning curve is going to be steep!

Mo Money, Mo money Haha

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MY06 STi

This is excellent advice! One thing I will add if it is the head gasket it will get progressively worse.

Swap for Cosworth or Tomei ones if it is. They are extra $ over the OEM but are sooo much better. Especially for the 2.5 which are prone to failure.
But a set of them and some decent headstuds will ensure it doesn't happen again.

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605whp
Quarter Mile in 10.9 seconds @ 135mph /217kph
0-100 kph 3.2 seconds

I was looking into going Cosworth Gaskets and Head Studs. Id be keen to see a comparison on Gaskets. OEM gaskets versus Cosworth gaskets. To see why they are better.

Btw dazdavies. Why did you not go with the Cosworth headstuds?

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MY06 STi