this is from scoobymods.com and im gonna post it here in case some of you don't know about that site or check it very often.
Originally posted by MisterX over on WRXFanatics.com in this thread
I learned about this problem on a post on NASIOC where I've seen pics of coolant systems clogged pretty badly with paint chips. This mod is a bit obscure but that doesn't mean it's not important. The facts of the matter are, Subaru painted the lid of coolant reservoir for the turbo on earlier models. On later models, the lid remains unpainted. The problem is, the paint on the underside of the lid of the coolant reservoir blisters, peels, and clogs your coolant system. Later models are unpainted. I guess Subaru decided there was a problem.
If your turbo coolant reservoir is painted black, you're going to have a problem. Here is a pic of me removing the coolant hoses from the top of the turbo coolant reservoir. Notice, it's painted black. As I said before, later models are unpainted.
Ensure engine is cooled down.
Remove Radiator Cap
Remove 3 coolant hoses and make sure to hold them upright so they don't leak alot of coolant
Remove the six 10mm bolts
Use paint thinner or remover to remove the paint on the underside of the lid. Or use a dremel on the lowest setting and grind it off (like i did)
Wash off with water
hope this helps people out who are anal about thier REX, like i am, plus, it only takes about 10-20 minutes to do.