I just tested my 97 legacy outback 2.5 dohc with 188k miles. The car does not overheat, just has a slight blip in the idle. Gets kind of sluggish every once in a while. I hooked up my compressor to the engine using part of my compression tester. The driver side of the engine is tight, just a very slight leak, barely audible, on number 4. But the passenger side, number one, is really bad. But I'm confused. At TDC, I hook up the compressed air and you can hear it leaking out the intake AND the exhaust. enough that I was able to put my hand on the tailpipe and feel the pressure. Same thing with the intake. Now when I think about the leaking, it makes me think it's coming out the valves, like they aren't sealing. Now the number 3 cylinder is leaking out the intake as well. I was expecting to see a blown head gasket, which would cause leaking out of one cylinder, but I guess it could cause leaking out of both. If the gasket blew, how could the air get to the intake and exhaust? I was trying to picture this dohc head, but I have only seen the sohc heads off, so I'm trying to make sure that it's the head gasket. I really hope that the head isn't cracked. I've read a few posts about blown head gaskets, but I haven't seen much comment on cracked heads or symtoms of. One other question is if a normally operating engine is run with the radiator cap off, will the coolant overflow or not. Mine comes out very slow and consistent. Just barely flows over the rim. I only let it do that for about 10 min, and the temp gauge stayed solid in the middle. If it is the head gasket, can you change it in the car, or is that too much trouble? Just take the engine out, I know it's not too bad to pull. Do I change both gaskets? or just the one that's blown? I've heard all the bad stories about this engine and head gaskets, but I figure it's worth $200 to change the gaskets and see if I can get another year or so out of it. I'm about to start on it this afternoon, so any advice is appreciated.