How much back pressure (blow-by) is normal?
It's a '92 2.2L with 166,000 miles. It runs smooth at all rpms and doesn"t
smoke. When I remove oil fill cap on valve cover with the engine idling. I get
a blast of hot air spewing drops of oil coming out. Is this normal? Does it indicate problems or future problems wit valves or rings?
jsatx '92 honda accord LX 2.2L automatic

 

replace your PCV valve. FWIW, back pressure and blow-by are 2 different things.

as far as it being "normal", i wouldn't say it's abnormal.

 

You should have suction into engine at idle, not pressure, so PCV could be faulty as Dr. D suggested.

If you put a piece of paper over the oil fill inlet, it should suck closed. It could be that engine has aged to point where there is enough blowby past rings to cause a net positive pressure.

Worst symptom of this is oil/blowby is pulled into throttle duct PCV air inlet and additional oil consumption. Some have placed an oil trip in the air inlet to reduce amount of oil pulled into engine. All engines occasionally have positive crankcase pressure (under throttle) and pull oil vapor into throttle duct.

good luck

 

Thanks Dr.D and TexasHonda.