I'm working on a friend's 84 Cabriolet. It's a 1.8 JH engine. It was leaking a lot of oil, but running fine until last week, then, no poop.
Dry/wet compression test: Cylinder #1 has 76 lbs of compression , the others all 175-180 . Squirting oil in #1 produced no change.
Leakdown test: big hissing sound at 100 psi (correct setting for this gauge), 80% leak on #1. All the others 15-20%.
Pushed on top of valve spacers to open each valve on #1, leak went to 90% but right back to 80% when I released pressure, both valves. I think this means they're both OK.
With air to #1, heard hiss everywhere with metal probe on mechanic's stethoscope, so removed the metal probe and listened around with just the hose.
Listening to air intake hose, no hiss. Listening at exhaust, no hiss. Listening at dipstick, no hiss. No bubbles in coolant. Leaning over #1 cylinder (valve cover off), feel air on my cheek. listen around #1, hear hissing, air seems to be coming from hole right next to headbolt in front left side of engine (engine's in car sideways - this is the corner headbolt closest to the firewall).
So: Head gasket around #1? Busted ring(s) in #1? Chipped/busted #1 piston? Any road, I think the next step is to remove the head, but wondering if there are any other steps before I undo all that stuff and take the top off this engine. Any advice?