The 2.1 in my 89 syncro is showing low compression , 110, 132, 150, and 160 this is after engine is warm. When checked with engine cold it is much higher. why is this? My main question is I was told to do a leak down test. I know what gauge to get but thats about all I know. How much pressure do I put in and how can I tell if it's the valves or rings leaking down or what else can be learned from this test?

Thanks,
Chip