HG gone as I lose water on overflow
 

During my map the water temp was a bit on the high side, so I suspect the thermostat may be playing up, anyway I have been keeping an eye on the temps and all was ok. After I had been pushing the car a bit hard it instantly overheated ( temp went up near the red ).
I slowed down and the temp stayed the same, up high but not in the red.
Any way got home and I am loosing water on the overflow on the rad so I suppose the head has lifted and the HG has gone.

Options I have will be new HG (cosworth) and uprated studs as I thing its got standard ones in.

Should I split the bottom end to change the shells ?

I ask as its more expense and the engines just been rebuilt , its covered about 400 miles.

I have changed the thermostat to a low temp one but i still loose water as soon at the car is up to temp.

its a 2.5 with V4 heads and forged. I run a 20G billet with 1 bar of boost @ 280 bhp, so very conservative map and its a little on the rich side.

1 pot is a little over tolerance , off the previous build, tiny bit of slap if you have det cans on , you can hear it when its running. I think it has CP non offset pistons.

With the engine loosing water its only done the odd stop start after the thermostat change , but it loosing water.

LOsing, one "o"........

Loosing means to let loose;)

OK, have you had a sniff test done? It MIGHT just be airlocked, if whoever built/fitted the engine didn't take sufficient care filling with coolant.

Get that done, then come back to us.

def no air locks, its been filled lots and done correctly , just dribbles water all the time. Engines gonna come out , just dont want to split it really.

Any steam from under the bonnet? You may have a pin-prick hole in a hose?
It seems quite a low state of tune to experience head lift?

nope , no steam, just dripping water. its a HI comp engine , pulls really strong low down.

water loss only from the overflow

Sorry, just trying to eliminate the simple (cheap) stuff before you take the heads off... I've experienced failures of the expansion tank, and the filler cap. Possibly try a 1.2 or 1.4bar filler cap (if I remember correctly, this goes directly to the overflow but I might be wrong!)

interesting point I will give this a go, just for piece of mind. its a good upgrade anyway to get new caps. Also I am going to change the rad to.

Caps are pretty universal, if you have any other Japanese cars from the same era, you should get away with a temporary swap..

I am out of the country for a while, so it will be a while before I get a chance to sort it. Strange it only started to have problems after a spirited drive , I do like to rev my wrx, so thats a bad thing, maybe I should drop the rev limit

That's what made me think airlock, the revving thing.

DO get a sniff test done before doing anything silly.

DO tell us EXACTLY how it was filled in order to ensure no airlocks.

It was filled by a pall of mine who is a bit of a Subaru specialist, the car was ok for about 2 tanks of fuel , no probs, but as I knew the temps were high when it was being mapped I keep one eye on the temp needle, and I saw it rise. I was shifting at about 7.5K along a (private) B road , quite a handful LOL

The garage I use always says its a problem not to air lock a subaru and spends a lot of time to fill the engine, about an hour he says. Cant help think I just pushed it too hard, the prob has got worse to, so changed the thermostat for 70 Deg, and now I have just stopped running it. I will change the caps to see that there is not a simple s/ change them solution, if this fails then I suppose I have a bigger problem. What about the bearings ? change them or risk it ?

Is your oil contaminated? If not, leave them be...

Thanks for the reply, I will see who can do the work in the North East area and get the oil inspected when I get back and get some prices for the worst case scenario ..

North East:

AS Performance.
DLM Motors, Percy Road, Darlington.

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