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stupid question, DIY common sense

Joined
23 July 2003
Messages
3,732
Location
Seattle, WA.
Since the search is down, I need to ask the following question..and yes I'm being oxymoron again...

I found that based on owners manual, it suggests whenever the oil at the oil dip stick reach the lower mark, put in one quart oil to bring it up to full mark...

The question is, when should I check the oil?? I had changed oil for all my family cars, but the nsx is the one that had "drastically" reach different mark according how long the engine sit from running...

If I just shut down the warm engine and check the dip stick, it's at the lower mark.

If I waited 5 minutes, it's actually showing 2/3 to the full mark.

I just checked it while I left the car sit for an hour, now it's probably less than 1/5 from the full mark.

:confused: so, is my car low on oil???
 
NO.

You are fine!

Oil is distributed throughout the entire engine via small bored out tunnels in the block and cylinder head called oil passages.

When you turn the car on, the oil pump, driven by the engine pumps oil from the sump (pan) to the rest of the engine. This is how you circulate oil through various moving parts needing lubrication, the pistons, crank, connection rods, heat-exchangers to cool the oil, and lastly the oil filter.

When you shut down a piston engine, there is still a significant amount of oil left in the cylinder heads, adhereing to the valve train, rocker arms, cams, etc. There is also oil remaining on the connecting rods and crank journals. Due to the viscosity of oil (compared to water) there will be some time before gravity can pull it back down through all of the passages and back into the main oil supply - the sump.
 
I believe the owner's manual to tell you to check the car after it's warm and has been shut off for 5-10 minutes. However, the reading should be similar to the reading when it's stone cold.
 
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