Let engine cool before checking oil level?

[thevictor390]

Needless to say, I will be checking my oil level a lot

My father and uncle both say to wait and let the engine cool beforehand, to let the oil "settle." On my old car I always followed this, but it would be a bit of a pain now. Yesterday I checked immediately after a drive, and again after the car sat for about an hour. Exactly the same both times. However, the engine was still pretty warm, some parts even uncomfortable to touch.

Is it necessary to let the engine sit/cool before checking the oil? If so, for how long?

And I have to say that for a car that burns oil by design, the dipstick is in a fucking retarded place between two hot pipes at the back of the engine.

 

[LeVeL]

Your father and uncle are correct, you should let the engine cool down. Just check it in the morning before going to work or wherever.

 

[Nabster]

I'm not horribly familiar with rotary engines, but I'd be willing to bet the oil circulation is quite a bit different than a piston engine, so waiting for the oil to settle is probably unnecessary.

 

[narf]

While it is usually recommended to let the oil settle, if all you want to know is when to top up you won't really need any wait, no matter if it makes a difference or not. Check at any time, if it's below minimum then top up. Any amount that may settle will not be a lot, so even if some bits flow back later you should top up anyways

 

[argatoga]

I'm not horribly familiar with rotary engines, but I'd be willing to bet the oil circulation is quite a bit different than a piston engine, so waiting for the oil to settle is probably unnecessary.

The oil still drains into an oil pan.

Anyway, just check the oil after 30 minutes or so. You only need to do it once a week.

 

[Zuhaib]

See this is different then what I have heard or read in the manual of any car/motorcycle I have. The GTI calls for the engine to be at operating temps, shut down, let it cool for the oil to return then check. I do that usually right after I fill up for gas as I had the engine running to get to the station and it cools a bit while I am filling.
Harley same thing, operating temps, shut down and allow oil to return and then check.
Merc has no dip stick o_0 really you check with MFD.

It makes sense as oil expands with heat, so if your checking cold oil you have a chance of overfilling if you think you are short.

 

[thevictor390]

Thanks for the responses. I guess I'll check the manual and see if there's anything in there about it. As long as I'm erring on the side of safety it doesn't seem to make a huge difference.

 

[thedguy]

The most accurate way to tell is to do it before you've started the car for the day (most oil in the pan), obviously if the manual says to check after engine has been warmed and all that then follow it.

I always check my oil before I start the car in the morning, and I also will randomly check it (when I remember) about 20 minutes after I've ran the motor. Warm oil is thin, it'll drain back petty fast, 10minutes should be MORE than enough time for it to get all back in the pan. Your RX8 doesn't have the drain back issues an engine with a valve train and oil restrictors in it so it's likely to be less of an issue to worry about waiting long periods for drain back.