Oil Question - hot and cold

[mac456]

Hi Guys,

i checked my oil this morning when the car was cold and it was reporting that it was just under the lowest mark. "GOOD Job i checked when I did" I thought.

Went and bought some oil from halfords (castrol 10w 40), came home, re checked when it was warm and the level was at the middle mark.

Any ideas? I put abit in anyway just incase.

Also is ok to mix brands of oil?

Thanks

Mac

[new to vw]

Best to check oil when engine is cold bud....as long as the oil is the same viscoity eg 10w40w should be ok...Dont mix semi and synthetic though bud.....
The reason the oil has moved up the dipstick is down to when the car goes around corners, stops and starts accellerating the forces push the oil up the dipstick tube.....If I remember correctly there are no baffles in the sump to stop the oil from sloshing around...

[Agreeable Slick]

The reason the oil has moved up the dipstick is down to when the car goes around corners, stops and starts accellerating the forces push the oil up the dipstick tube.....

B+ for trying.

Reason for it being higher is because it's hot. Hot = expansion & it's a pressurised system.

Oh and you should measure it 10mins+ after turning the engine off. Water temp should be around the 90degree level. Reasoning = the cold oil has been sitting (lets say overnight) and it in its thickest state. Running the engine up to temp, letting it sit for 10mins or so, means the oil is now in it's fluid state and the time you wait has let it drain down to the sump from various galleys, this will give you a much truer reading.

[new to vw]

Learn something new everyday.

[mac456]

Thanks for the replies guys, Will do that on my lunch break.

So just to clarify, Turn the engine on till car is up to temp. turn it off for 10mins and then recheck?

Say after doing this check and the level is around the middle mark. Where would it usually be if it was cold?

[Agreeable Slick]

So just to clarify, Turn the engine on till car is up to temp. turn it off for 10mins and then recheck?

Correct.

Say after doing this check and the level is around the middle mark. Where would it usually be if it was cold?

It would be roughly 6-8mm lower. When cold the oil is like treacle, but as it warms up the viscosity of it drops so it gains a bit on the dip stick as it expands to occupy more volume of the sump. Ideally the oil should sit between the top and middle marks after doing the above procedure.

[mac456]

cheers :-)