Today I had the engine running at idle and took the oil cap off and notice a good amount of air rushing out with a little spray of oil. Is this normal on a 99 corolla 148k on engine? Should I be concerned? Thanks.
Usually if air is rushing out of the oil cap, it is a sign of high crankcase pressure, usually caused from a plugged PCV valve or a hole in the piston.
If the engine is running fine, replace the PCV valve.
I guess it depends on the engine, I pulled the cap off a V6 Toyota motor once while it was running and the motor stalled. Wouldn't idle until the cap was back in-place. I'm thinking it had something to do with vacuum but never pursued it.
Usually if air is rushing out of the oil cap, it is a sign of high crankcase pressure, usually caused from a plugged PCV valve or a hole in the piston.
If the engine is running fine, replace the PCV valve.
No, because the combustion will half push the piston down and half go into the crankcase. It's rare to get a hole in the piston without the entire thing shattering, but it does happen.
