Oil Pressure Question

[jmp]

Yeah, somebody at the BCCC suggested an oil change too, so I was planning on doing one. I also figured it would help determine:
a) the quality of the old oil
b) how much oil is in the car now
c) how much oil the car will hold
d) if the dipstick read correctly
e) how much oil is in the car before it registers on the stick

Your method sounds pretty good (and pretty thorough), so I'll do that. Thx.

One question though: why clean the engine before hand? The engine is very clean; there was no (obvious) oil leak.

Oh, btw, now that I'm overfull, the oil pressure needle stayed constant; it was only when I was low that it jumped about. I'm still doing an oil change though!!!

 

[Jack]

/jmp ... One question though: why clean the engine before hand? The engine is very clean; there was no (obvious) oil leak.

jmp:
If it's already clean ... no need to repeat. Will be of interest to know how gage acts/reads from idle thru cruise ... with known 5 qt fill, no leaks and at full operating temp. Let us know.
JACK:gap

 

[vettepilot]

from what you have described about the oil level being low, then was way too high I would suggest you pull the rocker arm covers and look at your oil return holes on the head. If they are partially clogged with sludge, they will not allow the oil to drain back as rapidly as it is needed by the oil pump. This could lead to cavitation of the oil pump, and fluctuations in pressure. Then when you check the oil immediately after shutdown, it would show (incorrectly) low oil level. After sitting for a while, the oil has had a chance to drain back into the pan, and if you did add oil to bring it back up to the normal level, it would now present an overfiled condition. You might even avoid pulling the rocker covers in the following manner:
1. Check the oil level before starting the engine.
2. Start the engine, let it warm up to normal temperature.
3. Increase the RPM to about what you would see at highway speeds, (about 2000-2500), and hold it there for about a minute.
4. Now back to idle for a few seconds, then shut the engine off.
5. Check the oil level within 1 minute after shutdown.
6. If it is low, how low? Now check the level once every 60 seconds, until it indicates the level before you started the engine.
If it is taking that long to drainback then I would be looking for clogged return holes.
vettepilot