I did a search but didn't find any responses to the pilot's (A. Wick) statement that the overheating & warping of the head was due to air left in the cooling system. This would indicate that the headgaskets were not faulty but operator (or mechanic) malfunction when changing out the coolant... leaving just the least bit of air in the system causing the problem. He indicated that a special purging system needed to be installed (just in case?)

I have seen quite descriptive posts regarding the replacement of coolant (burping the system)...

Is this the real answer? does it only amount to a VERY thorough coolant refill?

Since other vehicles have this problem (resolved with this method) & this man risks his (& other's) life to Subaru 2.5 engines.... you can't coast off to the nearest cloud, after all....

Later,

Peter

You could search for my "coolant replacement without the air bubbles" write up. It's taken me a while to refine the method, but it's quite easy and works every time.

 

I do not believe that a small amount of air in the coolant system can take the blame for all the EJ25 problems. Certainly, local overheating would stress any block-gasket-head junction, but in the end it comes down to bad coolant passage design. Why isn't that air purged automatically by the overflow system??

 

I think the newer radiator designs (models from around year 2000 and up) have helped a lot in the air-purge department. That bulge on top, that the radiator hose connects to is now the highest point in the system. Even higher than the cabin heat exchanger in my Impreza. This is a BIG help.

You could search for my "coolant replacement without the air bubbles" write up. It's taken me a while to refine the method, but it's quite easy and works every time.

 

I do not believe that a small amount of air in the coolant system can take the blame for all the EJ25 problems. Certainly, local overheating would stress any block-gasket-head junction, but in the end it comes down to bad coolant passage design. Why isn't that air purged automatically by the overflow system??

 

I think the newer radiator designs (models from around year 2000 and up) have helped a lot in the air-purge department. That bulge on top, that the radiator hose connects to is now the highest point in the system. Even higher than the cabin heat exchanger in my Impreza. This is a BIG help.

Where is this writeup of how to avoid air bubbles? I looked in the USRM and it's not there.

Tadaaa!

 

 

http://www.ultimatesubaru.org/forum/showthread.php?t=21681&highlight=Coolant+Replacement

Very interesting. A lot of this is common sense when you think about how cooling systems are designed, but since when do most people use common sense? You should definitely post that in the USRM now.

You could search for my "coolant replacement without the air bubbles" write up. It's taken me a while to refine the method, but it's quite easy and works every time.

as I recall, I did copy that post so I'd be more prepared for the task... I have found that your posts & responses tend to be more to the point of factual information & a little less emotional replies...

Thanks for that.

Later,

Peter

Thank you :-)

 

Emotions are certainly running high now .....shedding a little tear ;-)