I recently acquired a Legacy 2001 with the 2.5 normal flat four boxer EJ251. Slowly but surely I have had an increasing overheating problem which recently resulted in me changing the cylinder head gaskets but this has not solved the problem. I have changed the thermostat and water pump along with flushing the radiator (which was a problem).
I am having the same over heating problems and getting worse?
Any ideas what could be wrong?
An mechanic I spoke to suggested that the block was porous and letting in compression gases, this sounded sensible as you can hear a lot of air in the heater matrix the londger you drive, someone else suggested that the cylinder head could be cracked although a crack is not visible??????

 

Seeing as replacing the head gaskets has not cure the problem,I would recommend you have the cylinder heads pressure tested/hot tanked as they can crack internally between the coolant gallery and the exhaust port area.

Mick

 

air lock ?

 

With regards to an air block I have put a bleed vent between the engine and heater manifold to fully bleed any air out but it still builds up as if compression gases are entering.

 

k-seal it see if that sorts it

 

Sounds logical but also expensive, in the mean time I have brought an MX5 to keep me mobile so I dont need to rush into anything. Thanks