Originally Posted by crankshift
Hope everyone is doing well.. I am very close to buying a 2005 legacy GT w 97,000km and came across this thread.
If I check all cylinder compression and it looks good would it be safe to say the car does not suffer from this burnt valve issue ? What should each cylinder read?
I would suggest a leakdown test if you want to know for sure if the exhaust valves are sealing ok.
A compression test is not as telling. If one of the cylinders is experiencing a serious compression problem you can easily see that with this test but if there are multiple issues in multiple cylinders, or there is only a slight leak (like a slightly bad valve), you may think everything is fine.
As far as # readings for compression tests, you are looking for the numbers to be close to eachother for the test to be considered a success. The actual values are not as important as the relation to the others. Also, I have since forgot what the Subaru spec says for this.
(keep in mind that if you take someone's car and have it checked that you need to tell the mechanic to not completely disconnect the ECM from power... if so, the adaptive idle program will be lost and it will idle like poo for a weeks while it get re-learned.)