zetan

Armed with a Harbor Freight cylinder pressure tester, and a 19mm 12 point socket for the crank, I began the leak down test yesterday on the 92 Jetta GL 1.8.

Holding a screwdriver in the spark plug hole, I rotated the crank
clockwise and to find TDC when the screwdriver was at the highest.
Also saw that #1 TDC aligned with the timing mark on the
top cog.

All 4 had a little air coming out of the oil filler tube. Air past the rings.
Same amount of flow on all cyls I think.

After several tries making sure I had TDC and the valves closed,
a little air escapes from #1 into #2. Worn rings or gasket?
No sound in the valve cover holes, so probably not valves?

#4 was the only one that actually registered a pressure drop after I set the gauge to 0 (70psi in tank, 15 psi on gauge, % gauge to 0). About 10% drop, but the others had none.
#4 was the only one that had a wet crown
#4 has a crack across the face that I can feel with the screwdriver.

No radiator bubbles. TINY bit of black on floating on top.
No exhaust sounds.
Opening the throttle lever changed the air tone slightly but didn't sound like a leak.

The car still starts, but idles high and misses when I revv it, even gently.
Exhaust coming from the PCV hole.

The timing belt is new as of 2 months ago. Should I attempt to reset the timing?

Thanks
-Z

denisond3

What makes you think the timing or the timing belt needs reset? Usually installing a new timing belt is not something that requires re-doing for maybe 60,000 (Omni, Excel) or 90,000 (Honda) or 100,000 miles (Escort, Avalon, etc.)
Im not familiar with leak down testing. I just go by compression readings and the color of the spark plugs. Worn rings would not be likely to the reason for pressurized air in cyl #1 coming out of cyl #2, since the gases would escape via the oil filler lid or the pcv valving, would it not?
The only sure thing about a leaking headgaset is that it will get worse.