'02 3.0i, 92k, burning quite a bit of oil now. Switch to 10w-40?

[TurnAround]

Starting around 56k my 3.0i started burning a bit of oil. Half a quart every 5k. That seemed somewhat within normal. Then around 65k it started burning more. A quart every 5k. I've always used 5w-40 (BMW recommended), and up to that point I was using BMW Castrol.

At that same time (65k) I had a discussion with my indi mechanic and did some posts on this board about a progressively higher and higher amount of yellow / gold paste sludge build up under the cap. The indi encouraged me to switch to Mobil 1 synthetic 5w-40. Many on this board did as well. The feeling here was that the Castrol did indeed lead to heavier sludge build up (iow, the normal accumulating condensation in the engine after shut off, wasn't then burning off very successfully on the next use).

I've been on Mobil 1 5w-40 since then, and up to my 92k now.

In the last few months I've noticed that I'm burning 1 quart of oil every one thousand miles. Umm.. that seems drastic. Not good.

I was thinking.. with those of you with higher mileage engines, have you switched to 10w-40? Would you recommend doing that?

But then also, I just did a search on the board here and I read a couple of posts that said do NOT use Mobil 1 because even though it says 5w-40 its actually still too thin by comparison to BMW's branded Castrol 5w-40. To the group here... do you agree with this? So like.. maybe the BMW Castrol rebranded thing isn't false after all?? I'm wondering, so maybe its indeed thicker, but also, that's the sludge build up cause as well.

Recommendations?

Thanks so much!

[mrbmwx5]

I'm at 200k+ and still running BMW 5w-30..
You need to check for leak at oil filter housing and oil separator.

[squeasel]

@ 130K on 2003 3.0 ... have always used 5-30 BMW Full Synthetic API SL. I would guess we use a quart every 4-6K miles. The SL-API has the right amount of ZDDP and I am unsure of Mobil 1 SM/SN so I didn't use it. Theoretically SM/SN should be fine (easier on the Cat Conv but with a little less lubricity). I have not been pleased with Mobile 1 0-20 in a Honda Civic Hybrid (though I am still in the early testing stages).

[motordavid]

Originally Posted by TurnAround

...I've been on Mobil 1 5w-40 since then, and up to my 92k now.

In the last few months I've noticed that I'm burning 1 quart of oil every one thousand miles. Umm.. that seems drastic. Not good.

...But then also, I just did a search on the board here and I read a couple of posts that said do NOT use Mobil 1 because even though it says 5w-40 its actually still too thin by comparison to BMW's branded Castrol 5w-40. To the group here... do you agree with this? So like.. maybe the BMW Castrol rebranded thing isn't false after all?? I'm wondering, so maybe its indeed thicker, but also, that's the sludge build up cause as well.

Recommendations?

Thanks so much!

That qt every thou miles is still well within BMW's 'spec', fwiw. Did you check for leaks? If none, the oil is being combusted via several possibilities.
None of us can know which is the cause, and a qt every thou would not send me to the rebuild dept.

A couple posts on Mobil1 being "too thin"? If you want some serious reading and even more opins, read the arm wrestles and tech stuff on BobTheOilGuy:
Passenger Car Motor Oil (PCMO) - Gasoline Cars/Pickups/Vans/SUVs - Bob Is The Oil Guy

I haven't memorized every poster's 'fave oil', but not many here are running 5W-40 of any brand; doesn't mean that is necessarily bad, just not a popular viscosity for E53s... Some of us run M1 0W-40, most run 5W-30 of a few brands.

You didn't mention whether or not your yellow sludge is gone...not sure I have recommendations other than maybe doing a change, (0W-40 or 5W-30), followed by a short time, 2nd 'hot change', and see how consumption is. But, you should look closely for leaks, too, imo.

Hey, another Oil Thread. ;>)
GL, mD

PS: I bet JCL, et al, the Mavens here, will have additional opins and ideas.

[JCL]

I wouldn't call it sludge, the yellow/gold paste is condensation that has emulsified. Oil sludge is black, and is caused by breakdown of the oil due to heat. The confusion is that real sludge is changed by which oil you use, but the condensate isn't much affected.

I like 5w-30, usually the BMW oil or sometimes Castrol, but I think Mobil 1 is fine, usually in a 0w-30 or 0w-40.

I wouldn't expect to see any change in oil consumption due to changing between oils in this approved range.

As MD says, you are within the BMW spec for oil consumption, although it would bug me too.

The most likely change to increase oil consumption will be driving habits. That is likely what caused more build up of the paste as well.

[caisson12]

Turnaround stated sludge/condensation under the (oil filler) cap.

I don't know how the CVV works but is it possible that the CVV is gunked up and routing oil to the intake and burning it in combustion instead of returning it to the crankcase?

[JCL]

Originally Posted by caisson12

Turnaround stated sludge/condensation under the (oil filler) cap.

I don't know how the CVV works but is it possible that the CVV is gunked up and routing oil to the intake and burning it in combustion instead of returning it to the crankcase?

Not likely. If it is clogged enough to not vent then it will pressurize the crankcase and push a gasket out, usually the valve cover gasket

If it is frozen it can freeze open and then siphon oil from the crankcase. That usually draws enough to make large clouds of smoke, it isn't metered to just a small amount

[amacman]

caisson 12 may be correct if the oil drain is blocked .
I think the oil drain links to the dipstick tube on the 3.0i engine .

[boostd92]

If the rubber diaphram in the CCV is torn, there will not be any external leaks, but the engine will actually suck oil from the dipstick tube (and combust it... your cats will catch it and because it's not a huge amount all at once, you won't see smoke out your tailpipe until it gets REALLY bad - but unchecked it's a good way to ruin a cat and those are BIG MONEY).

If you have no external leaks, I can almost garauntee you that your oil consumption problem is separator related.

The V8's are known to eat more oil (valve seals, etc), but the 3.0's shouldn't be eating any more than 3-4 quarts between 15,000 mile oil change intervals.

I'm an SA, and have had several M54 cars. When well maintained, I average 1-2 quarts between 15k intervals.