[Bertus]

Hi guys, I've checked a fair bit around the forums but haven't come across any useful info on my problem, sorry if it's a repost though.

the problem/question is this:

I just changed my oil for the second time since having owned my car (3.2L Euro).

Every time I change the oil though, it only seems to drain about 2litres, even though the dipstick is reading over full when I begin the process. So I roll the car forward a bit onto a bit of a slope, then more oil comes out. Anyway, I still can't seem to get it all out; there's meant to be about 6litres in there, especially with an overfull reading. Only about 3litres ends up in the drain pan.

(btw, the car is hot and is placed on 100% level ground and the oil filter is replaced as per usual workshop procedure on first attempts, etc.)

then, when I top it back up, it only accepts about 3litres and reads over full again once finished. (I realise it doesn't take a serious mathematician to calculate that I've put too much in. I only do this so there is plenty of oil to dilute all the old oil that's left in there which won't come out.)

I cant figure out why all the oil wont come out in the first place though. Is there something Ive missed? However, my main question is this:

What are the possible drawbacks or repercussions to running the engine with a little more oil, as in, a good centimeter over the full mark? Is it critical that I drain some out?

Sorry about my Aussie measurements. It's overfull by about the thickness of a cigarette or even a cigar on the dipstick and it only drains about half of what the manufacturer's handbook says is in there.

Any help would be seriously appreciated.

PS. I check the oil both straight after a drive and fresh in the morning before I've even started the thing. Either way, it reads overfull.
cheers

[Oogie_M]

From my understanding, the 3.2 liter euro-spec vehicles are equipped with an oil cooler mounted underneath the radiator. This oil cooler along with the oil lines can hold some of the "missing" liters in question during your oil change.

reference: http://www.realoem.com/bmw/showparts...03&hg=17&fg=05

The assumption would be that disconnecting these lines to drain the remaining fluid would yield more of the used oil during every oil change. However because the US-spec cars do not have this feature, I cannot comment on this procedure. I'd assume also that your oil pressure light would be on slightly longer than normal after your oil change if you did drain the old oil from the cooler (since the oil pump would have to circulate oil through the system and through the cooler first)

[Bertus]

Thanks a lot for your info! An oil cooler would explain everything, cheers.

And what do you think about running with more oil?
Only thing I can think* of is it might not be able to rev as responsive because of the further load on the crank to spin through the extra oil in the sump, although, the power loss would be very minute. Also, I think* it puts a bit of extra pressure on gaskets and seals.

*I don't have any proof, I don't actually know, I'm just assuming.

[zottyzot]

Originally Posted by Bertus

Only thing I can think* of is it might not be able to rev as responsive because of the further load on the crank to spin through the extra oil in the sump, although, the power loss would be very minute. Also, I think* it puts a bit of extra pressure on gaskets and seals.

I think that is a pretty accurate assumption.

Don't run it over full.

[M3Works4Me]

How much over full does it read?

Unless it is overfilled by way too much, it shouldn't be an issue.

For the North American cars, many of us overfill the oil by enough to bring the level up the dipstick into the first or second part numbers on the stick, and that can actually help prevent oil starvation during track or auto-X driving, but it would be less than say a whole liter more than the typical "full" mark.

If it's only a little overfilled it should be OK, but obviously there's a point where it becomes a bad idea if the level is too high.

[tbaker474]

Originally Posted by Bertus

Thanks a lot for your info! An oil cooler would explain everything, cheers.

And what do you think about running with more oil?
Only thing I can think* of is it might not be able to rev as responsive because of the further load on the crank to spin through the extra oil in the sump, although, the power loss would be very minute. Also, I think* it puts a bit of extra pressure on gaskets and seals.

*I don't have any proof, I don't actually know, I'm just assuming.

From what I've heard, overfilling the oil can lead to the oil frothing up. Oil frothing = 0 lubrication. This is just what I've heard and I'm not sure how much extra oil would make this happen.

[Oogie_M]

Originally Posted by Bertus

Thanks a lot for your info! An oil cooler would explain everything, cheers.

And what do you think about running with more oil?
Only thing I can think* of is it might not be able to rev as responsive because of the further load on the crank to spin through the extra oil in the sump, although, the power loss would be very minute. Also, I think* it puts a bit of extra pressure on gaskets and seals.

*I don't have any proof, I don't actually know, I'm just assuming.

Too much oil could risk whipping air into the oil, thereby causing foam/bubbles to form, which would lead to less lubrication and bearing failure (I believe the term is called cavitation).

[OahuMPower]

I dont know, I run close to 8 quarts with zero issues

I know a bunch of my track buddies without a dual oil pickup run close to 8 quarts as well

[M3Works4Me]

Originally Posted by OahuMPower

I dont know, I run close to 8 quarts with zero issues

I know a bunch of my track buddies without a dual oil pickup run close to 8 quarts as well

Exactly. Same here & no issues. You'd have to seriously overfill the oil to cause a problem, but foaming, cavitation & bearing failure would not be the result. Oil coming out all over the place might be, among other things, but even hydrolocking could result if you fill the block up enough...

Taking a high speed sweeping corner with low oil & high revs could cause cavitation and bearing failure, plain old high revs can cause foaming and valve train ticking depending on the oil, but a little more oil is always better than not enough.

[Oogie_M]

Originally Posted by OahuMPower

I dont know, I run close to 8 quarts with zero issues

I know a bunch of my track buddies without a dual oil pickup run close to 8 quarts as well

According to the Bentley manual, S50 engine oil capacity is 6.9 US quarts and S52 engine oil capacity is 6.3 US quarts. I've read that overfilling roughly 1 US quart is still safe for the engine.