Hey all,
 
 I finished a Frankenmotor build about a month ago. I used the short block out of a '96 OB, and the heads from a '96 Legacy. I surfaced the heads on my own via the flat board/sandpaper method. I used .056" thick Cometic MLS headgasket with their hybrid pattern. This is my third HG replace dealing with a Subaru motor, and I have other background experience with Toyota motors. I'm just trying to convey that I'm not unfamiliar with these things, nor to say that I'm an expert.
 I have found coolant seeping from the passenger-side head upon start up. It'll seep out onto the exhaust and smoke. After running to temperature/driving, the seepage stops and all is dry underneath. I have not seen any white smoke from out of the tailpipe; usage from the over-flow tank is not unreasonable. I followed the directions for headbolt tightening via the FSM. Doing this before, I've yet to see this seepage. But I was also using OEM headgaskets from Subaru. The MLS HG was pretty beefy. The rings surrounding the combustion chambers were aggressive. I've talked with some big-power-turbo Subaru enthusiasts, and they've mentioned different specifics for the torque. They use 30-60-90ft-lbs (I believe those were the numbers they referenced...) increment increases (first tightening is 30ft-lbs, second go around 60ft-lbs...).
 Is it possible that the FSM procedure doesn't squeeze the MLS HG enough? Can I safely tighten the head bolts now? Say another 25-45 degrees? Or is there an torque end-value that is actually achieved via the FSM process? Or is this a moot point, and I should be preparing for a HG replacement? I watch my gauges and fluids religiously, so I know that I could probably get away with driving it more without overheating.
 
Any advice will be appreciated.
 
Greg

 

Easily could not be enough pressure, the FSM procedure is for the factory HG gasket replacement. I'm not entirely sure if tightening the head bolts more is going to cause something else to happen. Strange that it is only doing it upon start up, if the bolts simply were not tight enough wouldn't it seep all the time?

Edited November 23, 201411 yr by TKFlight

Maybe it does seep slightly during use? I'm not sure. I just noticed that after driving, things were dry where they were once wet (during start up). Is it possible for expansion to take place after reaching operating temperature? It's just enough to stop or slow the seepage?

According to mitchel on demand there is a retourque procedure of 33 ft pounds after engine has been warmed up, but this is in the older composit gaskets the first gen 2.2 used

If you torque the head bolts down the same way on the drivers side, why isn't it seeping from the drivers side also? The coolant does expand when the car is at operating temp. Could one area of the passenger side head still have to much warp?

If you torque the head bolts down the same way on the drivers side, why isn't it seeping from the drivers side also? The coolant does expand when the car is at operating temp. Could one area of the passenger side head still have to much warp?

 

Unsure of the other side... I was wandering about the expansion of the head/block/gasket...

they normally don't leak so something is compromised if you think the torque procedure was followed correctly.

 

i would wonder about the block flatness - check it when you go to do the repair again.

ivansimports resurfaces every block he sees (which is a lot - like dozens a month) - i would guess he does that for a reason.

 

this doesn't usually work for Phase I's, but neither do Phase I's normally have your symptoms you're describing.  so...would it be worth using Subaru coolant conditioner which works in Phase II's?

Edited November 23, 201411 yr by grossgary

Are you sure its coming from between the head and block?

Seepage from the upper radiator hose would run down the front of the block into the same area on the passenger side.

 

If its at the back it could be from the crossover pipe on top of the block, or it could be from one of the small hoses that go to the TB and IAC.