scooby 60

I own an 06 hawkeye sti I have an overheating problem. I have replaced the thermostat but it still does it. When it over heats the heaters in the car don't work has anyone got any ideas what it can be. I thought maybe a faulty water pump it doesn't overheat all the time just every now and then but it's starting to **** me off!

Butty

iTrader: (2)

Head gaskets been checked?

tubbytommy

iTrader: (20)

its a 2.5
the head gasket has failed, they all do this...........

scooby 60

Had a lit and test that came back clear. Yeah it's a 2.5

chopperman

More likely to be a head gasket issue than water pump. Does it fill up the expansion bottle after driving on boost?

scooby 60

I don't even have to drive it on boost it overheated this morning after 5mins of driving. If it was the head gasket would it not overheat all the time?

scooby 60

Yeah the expansion bottle fills up

chopperman

Head gasket mate. One test you can do is take the pipe that goes from the rad to the expansion bottle, attach a longer pipe then run it up to the wind screen. Go for a drive and see if any water comes out the pipe while your driving. If it does you will know its HG. But if you have noticed the expansion bottle fill up after a drive i think it's safe to assume its the head gasket.
The best fix is to replace the standard head bolts with 11mm ARP studs and cosworth stopper gaskets are considered the best. The engine needs to come out to do this so it's the ideal time to replace the standard and troublesome pistons with forged items. Mahle powerpak are very good and reasonably priced compared to other makes. My advice would be to contact
either Paul Finch Motorsport or enginetuner or API or Stockcar to price the job.

scooby 60

Thanks for your help. What price will I be looking at just as an estimate would you say? To say I'm gutted is an understatement.

chopperman

I'm afraid your looking at at least 3k as a ball park figure but could rise a fair bit if there is other damage or work needed to repair the engine or you want to add other parts to the build for future tuning. If you just want a repair that will last running power levels of 400-450max i would just go for :
Mahle forged pistons
11mm ARP struds
Cosworth stopper head gaskets
ACL main bearings
ACL or mahle big end bearing.
That will make it the car it should of been when it left the factory.

I do feel for you buddy, i have been in a similar situation. Mine wasn't head gaskets. It was #2 and #4 piston fractures. Paul Finch motorsport re-built mine and its been great ever since. He goes by the name of MotorsGT on here. The others i mentioned are also very good and recommended by many here.

tubbytommy

iTrader: (20)

if the hg has failed though you still want to replace the bottom end bearings as the water can dilute the oil and wash out the bearings and they fail soon after the rebuild so its cost effective to do it while engine is being repaired.

chopperman

Agreed.

scooby 60

Ok lads thanks for the help don't know what to do now.

tubbytommy

iTrader: (20)

get it checked by a specialist and get some advice, i wouldnt get it done on the cheap either use a subaru specialist garage.

its not going to be cheap im afraid

Donz144

^ Surely that depends how long the HG's have been gone and how much overheating he has experienced? Mine failed last year (saga) and was not recommended to have this done. The 2.5 is semi forged anyway so regardless if you future proof it or not (now of course is a good time if you're in search for bigger power) dont worry too much about it. This has happened 100's of times before so don't loose faith in the car!

I had my Thermo, water pump, headstuds and HG's (cosworth) all uprated and opted to have lots of porting done to improve throttle response and spool time - what a difference, rather than chasing peak figures. This was thousands of miles ago now and it gets some stick! I did opt to have some gauges fitted to monitor things (it took me a while to stop staring at my temp dash gauge!!)

All in it cost me about £1500 (including new belts, tensioners etc). BTW way my WRX wagon puts out 370BHP

scooby 60

It has overheated about 3times but only once I let it get to hot before I turned the engine off. I love the car to bits the best I have ever driven. Mine is putting out 360bhp at the min.

chopperman

even if you dont intend on paying out for beareings it is wise to have them and crank journals checked for wear. Also the 2.5 is NOT semi forged. They use A hypereutectic piston which is a high silicon cast material. The silicon is used to reduce expansion under heat but also makes the ally brittle.

Donz144

Then don't stress dude. I was in bits worrying about it thinking my pride and joy had given up the ghost! It may even be worth you getting up here (Edinburgh) as your so close. I could put you in touch with my mechanic and he'll get you completely sorted (you could even have some porting done too!)

He sent me links to everything I needed to get including oil, coolant, HG's, Studs, Belts, tensioners etc etc and arranged for the heads to be skimmed before putting it all back together. It was off the road for 3 days.

It will then need a remap of course but will run OK (of boost) until then.

Just a thought if you're not hooked up with someone down your way. Of course if you have the money do some forging then you should consider contacting Litchfield or Powerstation that are not so far away from you (?)

tubbytommy

iTrader: (20)

get some specialist advice, as they are not semi forged at all.

Donz144

Thats the one

tubbytommy

iTrader: (20)

and they are sh1te, replace with proper forged ones

scooby 60

I might take you up on that offer Donz144. The garage I go to is ringing subaru up tomorrow for some advice to see what they say and I will go from there.

chopperman

All i will say is "do it properly or pay twice".

tubbytommy

iTrader: (20)

We tried

Donz144

I'm sure. 78,000 miles of happy, hard motoring with these though so I'll give em a wee bit longer

No worries man, I'll give him a nudge and let him know. These guys don't know who I am talking about as I'll not take liberties with his name but they'll probably know him! He's a Subaru specialist building engines and turbos for lots of us up this way with a great track record.

I agree with them completely 'do it properly or pay twice' but that does not always mean spending huge amount of money. I've spent lots of money with lots of tuners over the years so I know a good one when I come across one but don't just rely on my word for it, lots of others will testify to his level of workmanship including Mr Forrest himself who asked me specifically who was responsible for my excellent build while he was mapping it on the road with me!! Testimonials don't get much better than that in the UK scooby tuning scene.