Questions and Answers

Nissan Stanza No Compression, Knocks Q. When the engine revs up over 2,000 rpm or has a load applied to it the engine will start knocking. Ran compression check, cylinder #1, 3 and 4 have 160 to 170 psi, cylinder #2 has 0 psi. Timing chain is tight. Pulled head, valves appear to be seated correctly, head gasket looks okay, no trails, piston is tight, no side movement, no marks on cylinder wall, broken ring.

Also when engine was running it had a lot of vacuum in valve cover when opening oil fill cap. Hope someone can give me some ideas on what to look for.

• 1992 Nissan Stanza
• 2.4 liter
• Automatic transmission
• 172,000 miles
• P/S, A/C, Cruise control

Thank you,
Rich

A. If you 0 psi in cylinder # 2, there is a reason for it. The cause can be either bad valves, bad rings, or cracked cylinder head. Usually bad valves are accompanied by backfires either through the intake or exhaust.

If you can see nothing obvious, then you will need to dig deeper into the engine. It's impossible for me to try and imagine what the knocking sound you heard is, but if it came from the bottom end, you probably have bad bearings, although you would still have some compression.

Did you try turning the engine over by hand and watching the piston to see if it moves? Sometimes an engine will throw a rod, and it will make a loud knocking sound.

I think the next step would be to take the oil pan off and have a look inside there. I'm almost willing to bet that a rod is thrown.