Jump to content

Help...2005 Legacy GT 2.5 - Compression


Recommended Posts

Main question: Compression test (cold) 173k miles =





I've read that they are supposed to be above 100 psi. it's also burning oil pretty quick.


So I had a trouble code of P0303...Took off coil of #3 cylinder and the connector just fell apart in my hand and the wires fell out of it. Went to 3 parts stores and the dealer, can't get pigtail to replace it. Dealer found one on amazon. So as I'm waiting for it to arrive, I decide to replace all the spark plugs. "WHAT A PAIN". Took hours to get them all out, no room to work.

So since I had all out, decided to do compression test. Results are above...

I am an honorary mechanic depending on the Internet for assistance with repairs.

Link to comment
Share on other sites

Just call AWD Tuning and order a new longblock. You will have to ship them your heads once you have the old engine out as there is a core charge. They wont want the block/pistons.


Why a long block? Because it is cheaper than having a shop transfer heads, head gaskets, head studs, timing belt, water pump, etc. from the old motor to the new.

Any decent shadetree mechanic (ie: you) should be able to transfer all the external ancillary bits over to the new long block.


Also, you could just order a complete used engine from a reputable online source (like jspecauto). This will be the cheaper option.



I have no affiliation with AWD Tuning other than I buy engines from them and they do good work.

Link to comment
Share on other sites

Most likely, it IS done, given that it's also burning oil, P303, etc.. However, I had my generally trusty "general" mechanic come up with ~70-85 psi of compression all around doing a general "compression test".



Went to a Subaru specialist who did a Leakdown test, not compression, and got something like 5% / 7% leakage (95 / 93% left? Not sure if that's the right terminology), which was just fine for a 130k motor which has been at stage 3+ since ~60k.



Subaru specialist also said he never does compression tests anymore for Subarus, because leakdown is much more reliable. So, if this is your first compression test, it's POSSIBLE (just maybe) that your engine is still ok.. Depends on how much longer you plan on keeping it.





Link to comment
Share on other sites

Sounds like something was up with your compression test.


Because with compression that low you would have been misfiring on all 4 at idle.


I like to do both tests. Compression for the quick block check and leak down to test for leaking valves. Generally I already have an idea of what I am looking for and just need to verify.

Link to comment
Share on other sites

Agreed. But if the OP's car was running ok, then maybe he made a similar error? He did the compression test himself as an amateur (the way I read his post), so I was just saying it's possible his car may (emphasis on may) not need a new shortblock (yet).
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Create New...

Important Information

Terms of Use