Engine Oil Level

[Wezzel]

When I check my engine oil level first thing in the morning on a cold engine the level is on the max.

If, however, I run the engine, leave it to cool for a while (whether it's 5 minutes or 1 hour) the level is quite a bit lower.

Which is the correct way of checking? I know it's not a good idea to overfill.

 

[nickmann]

The oil has drained into the sump overnight, and the sump is where the level is read.

When you start then engine, oil is pumped around inside the engine. It fills passageways (called galleries), also the oil filter, and sploshes and pools a bit under the cam cover.

When you turn it off, it starts draining back down toward the sump. At the moment of turning off the engine, the level will read quite low, as a fair amount of oil is still up in the motor. As each minute passes, more oil drains into the sump, and the level will read higher, until after an overnight rest it will show its highest.

I would suggest that waiting about 15 minutes is about right. As your highest ever reading is on max, I suggest your level is OK.

 

[silverarrow]

over night best cold block

 

[Brian WH]

over night best cold block

I agree, that is the only time to get a "True" reading. Ensure the car is on a level surface or you will get a false reading.