Only compression on 3 cylinders. One cylinder no compression. What could be the problem ?
Bent, stuck or burnt valve.
Possible head gasket - after all it is a Subaru.
or possible head gasket. F_O_R is correct, after all it IS a Subaru.
Do you have a leak down tester? It could also be rings. Leak down test can help you identify between intake vs exhaust valves, rings, and head gasket.
No compression on one cylinder is likely not the rings.
Agree with Bob. Bad rings would mean low compression but probably not no compression.
Way to miss the forest for the trees boys
Much more likely to be a dropped valve guide related. Drop exhaust and look for it hanging there.
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