Burning oil @ altitude

[JohnShannon]

I have a meticulously maintained 99 M3 with 110k miles. I ran synthetic for about the last 5k miles and after taking it into the shop I was informed it had lost atleast several quarts of oil. The car has 0 leaks and is bone dry underneath. Shop is a reputable place and they could not find any cause of the burning oil-crank case vent value appeared to be new and no loss of oil there. I do live in Denver and drive the car pretty hard-mostly highway miles between 70-90 mph. I have also taken the car to even higher altitudes for mountain drives.

My questions:
Given the altitude and driving conditions, can this be common to burn this much oil?
Are there any hidden/uncommon areas for the oil to be burning that my mechanic may have missed?

Any thoughts/feedback would be greatly appreciated as I'd like to keep the car as nice as possible. Thanks for your time!

[mitch500]

If you burnt 7 quarts you would have been completely empty.

So you say oil cyclone separator is new?


Sent from my iPhone using Tapatalk

[JohnShannon]

If you burnt 7 quarts you would have been completely empty.

So you say oil cyclone separator is new?


Sent from my iPhone using Tapatalk

Several quarts, not seven. If oil cyclone separator means crank case vent valve, yes, the mechanic said it looked to have been replaced and was not causing the issue. (Sorry im not a mechanic)

[marvinstockman]

Before you dial 911, how many miles for how many quarts?

Also, what grade did you previously use, and what grade are you currently using?

[Midnightfreak12]

Hey I live in Denver too! I lose about 1qt of oil ish per oil change but i've read thats normal. the only time I've ever lost more than 1qt was when I went to the track. Like most people stated here, how many quarts are you losing per miles?

[mitch500]

Several quarts, not seven. If oil cyclone separator means crank case vent valve, yes, the mechanic said it looked to have been replaced and was not causing the issue. (Sorry im not a mechanic)

I don't get it. You brought the car to a shop and they said you burnt several quarts? As in all at once or over time? How do they know this? Have you been adding oil every once in a while and your keeping track of how much you have been using?

Also how does a cyclone separator or crank case vent valve look new? Literally the cyclone separator is buried under the intake manifold. Yes one can say it looks new but how do you know? It's a sealed unit, they would have to remove it, physically open it and look inside of it. You can't just look at the separator and say "oh it looks new"

My bet is its the oil cyclone separator. My 2 cents

I am using about 1 litre per 1400kms, I don't think is unusual. These engines use oil. I'm about to change my separator as I don't think it's ever been changed and I'm at 240,000kms (not miles)


Sent from my iPhone using Tapatalk

[boarder2k7]

I changed my cyclonic separator at around 145,000 miles. For me there was no discernable impact on oil consumption, or build up in the manifold. Upon opening the old one up it looked fine inside, the rubber diaphragm was still soft and moved properly.

I just rebuilt the head including a valve job, which I suspect should lower consumption. It won't be a fair test though because the mainseals, pan gasket, and oil filter housing seals were all changed at the same time as well.

[JohnShannon]

I don't get it. You brought the car to a shop and they said you burnt several quarts? As in all at once or over time? How do they know this? Have you been adding oil every once in a while and your keeping track of how much you have been using?

Also how does a cyclone separator or crank case vent valve look new? Literally the cyclone separator is buried under the intake manifold. Yes one can say it looks new but how do you know? It's a sealed unit, they would have to remove it, physically open it and look inside of it. You can't just look at the separator and say "oh it looks new"



My bet is its the oil cyclone separator. My 2 cents

I am using about 1 litre per 1400kms, I don't think is unusual. These engines use oil. I'm about to change my separator as I don't think it's ever been changed and I'm at 240,000kms (not miles)


Sent from my iPhone using Tapatalk

I took car to shop 1 who first changed the oil, 5k miles later I took it to shop 2 for another oil change. Shop 2 said oil was very low, and zero leaks on the car so they say it's burning- I can smell burning oil sometimes, kinda like vcg is bad but it's not. I'm assuming due to no leaks and driving 5k miles the oil loss was overtime- I didn't add any oil in-between changes not check the level. Shop said oil cyclone separator 'appeared to look new' from the appearance on the outside but said they could not confirm, just their observation. I've only driven the car 500 miles since the last oil change and oil is still full, Ill keep a close eye from here on out and keep you guys posted. Thank you all for your help so far!

[MauiM3Mania]

Some might consider me overly cautious, but I'd suggest that you check the oil level a few times between oil change intervals.

[Vitaliy]

Some might consider me overly cautious, but I'd suggest that you check the oil level a few times between oil change intervals.
This. Bmw even put a sticker on the gauge cluster saying this. Whats to say shop 1 even put in the correct amount of oil in the first place? I cringe when i read about people who never check their oil.

Sent from my SGH-M919 using Tapatalk

[DocWyte]

No way of knowing how much and how fast you're burning oil without you checking it regularly and charting how much you're adding. So start doing that and then you'll have a data point.

I live in Denver, my M3 is mostly a track car and I basically don't burn any appreciable amount of oil...

[jhott66]

This. Bmw even put a sticker on the gauge cluster saying this. Whats to say shop 1 even put in the correct amount of oil in the first place? I cringe when i read about people who never check their oil.

Sent from my SGH-M919 using Tapatalk

Agreed.
Also a sample of 1 is not sufficient to make and recommendations or conclusions.

My bet is the oil was not set properly at fill or shop 2 did not check it correctly.
Add oil as required, set the level correctly (typically to max mark on dipstick), check oil level at EVERY gasoline tank fill. This will tell you whether or not you are burning oil.


Sent from my iPhone using Tapatalk

[Ex36]

Doesn't BMW say oil consumption as much as 1 qt. per 1,200 miles (IIRC) for these engines is at the high end of acceptable? So, if you're at the high end and went 5,000 miles without checking it, all of your data makes sense. It just means you've got to check your oil frequently. I'm kind of in the same boat. I bought a very pristine 109K-mile car and assumed it must not use oil, but it does. Yet, there's no easy way to see where it's going (must be burned since it's not in a puddle on the ground). However, the car doesn't smell bad or run with smoke ever. Not at start-up, not flooring it. Also, I find that the consumption seems to vary considerably. If I have a period of many, super-short trips where the car doesn't even get up to operating temperature I use more than if I do a bunch of long hauls. I did replace the cyclone separator, BTW, and it didn't matter (I've seen this bandied around so much at this point I think it's internet lore and they are rarely bad).

[boarder2k7]

I did replace the cyclone separator, BTW, and it didn't matter (I've seen this bandied around so much at this point I think it's internet lore and they are rarely bad).

I'm pretty sure this is correct as well, based on the post replacement necropsy of mine.