Checking oil level on V12 XJR-S - oddness occuring...

[fizmo100]

Hi! I have a bit of a weird issue with my XJR-S. It's a 1990 6.0 V12, and checking the oil level has got me scratching my head. If I check the level when the engine is cold, the oil level is bang on where it should be, perfectly level with the 'full' marker on the dipstick. If I drive the car, park it with the engine off, and wait a few minutes, when I check the oil again the level has dropped dramatically, in some cases right off the end of the stick! (Obviously when I first withdraw the dipstick the level is still ok from when it was replaced after the previous check, but after a wipe and a recheck the stick comes out dry).

If I then leave the car overnight and check again while cold the level is back where it should be.

Is this something that is normal and has a perfectly rational explanation, or is it a sign that something is not right? I am open minded to the third possibility that I have pixies who top my engine oil up in the hours of darkness...

One thing I need to check is how long it takes for the level to rise once the car has been run and then parked. I know it takes more than a few minutes, and this strikes me as being odd! There's a small oil weep from the engine somewhere (not been able to track it down yet as it's partially masked by a bigger power steering fluid leak... on my to-do list) but it's nowhere near big enough to be causing these issues.

Any thoughts?

[Hooli]

Sounds normal to me. I don't know how long it'd take the oil to drip back down in those engines, but in any engine the level will drop when running. So it'll take a while for it all to run back down into the sump again.

[richw_82]

fizmo100 said:

Any thoughts?

Thats probably why the amount of oil the engine requires is so much, as once it starts to fill everything under pressure it uses quite a bit. From memory its around 9 litres or so it needs during an oil change.

[naki]

not sure if this applies to the V12, but on AJ6 engines, sometimes, oil pressure relief valves can stick and cause irregular oil level reading. maybe worth checking if its worrying you?

[fizmo100]

Thanks for the replies - that's set my mind at ease! I was just worried something may have been blocked somewhere preventing the oil returning to the sump. When I get a chance I'll run the car and park it, then take a reading at regular intervals and note down what the level is - that'll give me an idea of how quickly the oil returns to the sump.

On other cars I've had after parking up for a couple of minutes the level is fine, but then I guess they have smaller engines with less cylinders etc.

Anyway, I'll stop worrying quite so much! Thanks again!

[biglump]

Normal

[fizmo100]

Cool!