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Discussion Starter · #1 · (Edited)
So, this is becoming increasingly worrying, especially as just now it lost about half a quart or so in ~55 miles.

My usual consumption has been low enough that I haven't had to think of it much, I'd say around 1/1000 or 1/1500, which is perfectly fine and certainly what I would expect of this car.

I've been making many long-distance trips to Chicago from the Milwaukee area in the last 3 weeks, in preparation for a move there. So, lots of freeway driving, higher speeds (90+ mph) but generally steady-state and with cruise control often times. Almost all driving between 80-100 mph.

This started on a trip about 3 weeks ago, I noticed the oil level had dropped on the way down, which meant little, but then it dropped again on the way back, and this mean it was time to add a quart. When I returned home, I added a liter out of my LiquiMoly jug, and that was that. I drove it around town and a bit on the freeway, short trips. for the rest of the week. And didn't really notice that it decreased by a particularly large amount. This took me through Christmas, although by the end of the holiday weekend it had dropped a "peg" and so I was keeping an eye on it. On the next trip down that week, last Thursday, it dropped another peg on the trip down, and stayed there for a while...on the trip back, it then again asked for more oil. This seemed strange to me, as of course that meant it went through that liter in about 500 miles or so. I was concerned as I had to drive almost the whole way back that way, but I kept my speeds reasonable and never went full-throttle. I had also noticed that it went down from the halfway mark in the OBC screen to "add a quart" without stopping in between. That was the first time I ever remembered it skipping a level. That was also concerning.

I added another liter the next day. The following day, I made another trip to the same area. Sure enough, it lost about half on the way down, and once again, on the way back, asked for more. That was extremely concerning, as it seemed to make rather large "jumps" once again, and of course this only about 250 miles of driving in total. Extremely alarming. But, the car seemed fine. Apart from the system telling me the car needed more oil, there was seemingly no change in any behaviors whatsoever, no smell, no drips, nothing. So, I added more. I made another trip 2 days after that in a different car because I was concerned, but even in the brief driving I had done since adding that last liter it had dropped to half again by today.

Today, when setting off, it was still at half, and then after about 50 miles or so, suddenly it asked for more. Once again skipping the next lowest level. At this point, I'm thinking if it was something serious inside the engine, I'd know about it by now...must be a leak. But still concerned. I made a detour to Knauz BMW in Lake Bluff to buy a quart, dumped it in, and finished my trip. It was another 33 miles. On the return trip, it was fine for a bit, but after about 22 miles, it dropped from being completely full to one notch about "add a quart" - 55 miles in total travelled. And there it stayed for the rest of the trip, another 90 miles or so. And that's currently where it sits.

At this point, I'm extremely lost as to what could be happening, apart from quite a massive leak. However, no spots on the driveway, so it must be from somewhere that's pressurized while the engine is running. Oil cooler seems to look as it always has, engine bay seems clean, the filler spout and cap are new and remain clean. Engine runs exactly perfectly, no smoke, no smell, nothing. I know what burning oil smells like, the exhaust smells about as good as you'd want it to smell given a proper AFR and proper oil burn rates. Nothing has changed, except the oil is magically disappearing somehow. This change seemingly happened overnight, nothing like this has ever happened before.

The car needs an oil change, and I'm thinking I will take it to the local indy shop to have it done, and tell them to look for leaks as well. Are there any common places I should have them look? This car has never really leaked a drop of anything, really. There's not much visible without a lift, but I don't have access to one myself. Just want to know if anyone else has any ideas at all.

EDIT: I suppose this would all be helpful - car is an '08, ~90,450 miles, I use Liqui Moly 10w60, and that's all I've ever used. Consumption has always been very reasonable until now. Car had TWS in it when I bought it, and that seemed to burn about the same.

Thanks so much.
 

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Discussion Starter · #3 ·
I would not add more oil to it. Get the oil changed and check how much comes out. If it is really consuming so much oil, you should get smoke from the exhaust.

I suspect the oil level sensor is not functioning properly.

Good luck
I had thought about that, due to the extreme cold I wondered if that might cause a failure. I thought the same re: the burning, such a high rate of burn I'm sure would have an extremely noticeable effect on how it ran and would smoke like an oil fire. So at least I feel somewhat confident that it's not internal. But I am worried about a wild goose chase tearing half the car apart looking for a leak since it hasn't presented itself yet. Calling the shop tomorrow, going to avoid driving it until then.
 

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Yeah, I would not add more oil. Check your exhaust tips -are they black and covered with oily residue? If not, you are not burning oil.
 

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Discussion Starter · #6 ·
Exhaust is fine, nothing at all to indicate it’s being burned. Especially not at such a rate.

I do have some indication it might be leaking, at least under pressure while the engine is running - was visiting a friend shortly before this started, at one point I remember having it idle in one of the driveways for quite a while. He just let me know today that it left an oil spot, although I don’t know the size. However, seeing as it’s never left an oil spot anywhere before - that’s reason enough to think it’s leaking out. I will have it up on a lift tomorrow, going to measure how much oil comes out, hopefully the leak isn’t something major.


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That might not be a leak but rather it finally blowing out of some vent or intake etc. If it was leaking and you have added that much oil then the EPA would be calling you. Lol good luck. Hope it's just a sensor

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Discussion Starter · #8 ·
Quick update - car is in the air, whole front underneath is covered in oil. Trying to find the leak right now with the engine running. Quite a mess.


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Good luck. Check the oil cooler first
 

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If it's indeed a leak then you are lucky besides a bad oil sensor. Hope for the best and a oil cooler.

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Discussion Starter · #11 ·
So, as expected by many, it is indeed the oil cooler. Drips quite a bit while running. But something else is concerning, one of the VANOS lines also seems like it might be leaking? Cleaned the whole bottom with brake cleaner and drove it around the block, apart from all the oil that had already leaked out of the cooler, we saw this:


I’m not sure if it’s just spray from the considerable mess the oil cooler is making, but the other two mechanics I’m with seem concerned. Wondering if anyone has thoughts on this. Thanks so much for all the input.


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Discussion Starter · #13 ·
I don't see anything leaking.



Top to bottom you're looking at:

PS hose

Vanos accumulator hose (metal braided)

Secondary air pump hose


Thanks, was trying to figure out the rubber and I knew it wasn’t VANOS. Greatly appreciate it. I have a feeling it’s not leaking either, literally everything was covered by the cooler leak so it seems reasonable to assume that’s what that is.


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The PS hose is known to start leaking. Mine is sweating too, but only a little. Problem is, you have to drop the front suspension to get it out as it runs to the back.
 

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Discussion Starter · #15 ·
The PS hose is known to start leaking. Mine is sweating too, but only a little. Problem is, you have to drop the front suspension to get it out as it runs to the back.


Yeah I noticed that, looks like a huge pain in the *** to replace, not going to bother right now. The steering seems fine and doesn’t make any sounds so I’m not worried about it.

All this right as I really start to feel guilty about my rod bearings. Those are next...pretty soon there will be nothing left to break on this car.


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Yeah I noticed that, looks like a huge pain in the *** to replace, not going to bother right now. The steering seems fine and doesn’t make any sounds so I’m not worried about it.

All this right as I really start to feel guilty about my rod bearings. Those are next...pretty soon there will be nothing left to break on this car.


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Don't screw around with these. Get them replaced if you are above ~65k
 

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Discussion Starter · #17 ·
Don't screw around with these. Get them replaced if you are above ~65k


They’re on the list, have had so much going on lately that I just haven’t time, and every time I’ve set aside the funds something else happens. But it will be happening very soon.


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Oil cooler is definitely an easy DIY. Get a 6-pack and you'll be done in an hour.
 
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