04 E46 ZHP Burning Oil

[Scorpius]

So i've been throwing a few various codes, 171 and 174's mostly. Car has 245k on it.

Been going through about 1 qt of oil every 500 - 700 miles. which for me is weekly. Had my brother driving by me one day and he said under acceleration, especially heavy accel, that a black grey smoke comes out.

Of course two local mechanics tell me 1. replace engine 2. valve seals. BMW dealer says with this M54 engine he's yet to see bad seals, thinks it's the CCV valve ($1k job uhh nah DIY).

So what does the hive think? My engine isn't spotless mind you, but i also have no drips on floor, the under cover or anything anywhere on engine explaining the 1 qt usage.

VCG isn't leaking. So i don't mind doing the CCV but if i do, i'm going to go in from the front and just hit the OFH gasket since that's a MUCH easier path to hit this chnage out (I did it by the book from the right side (DISA area) about 2-3 yrs ago...shortly after my OFH gasket went and i was like dayum...this would have been much easier this way!)

as for the smoking...mind you I rarely see it in the mirror, when i have its been under heavy acceleration TRYING to see if i see smoke. At idle I don't see anything when i exit the car, though it does smell oily.

If i do this again i'm doing CCV, OFH, injectors (refurbs), new coils/plugs.

Thanks for the hive responses.

[BADCLOWN]

what are the 171 and 174 codes specifically, I'm unfamiliar.


recently i threw bank 1/bank 2 lean codes and it turns out my CCV is leaking. replacing the entire system (plumbing and all). mine was burning a small amount of oil due to the leak. i don't know/again unfamiliar with how much oil it would burn in a week if the CCV was the issue.

[Avetiso]

The codes are lean codes. You probably have a vacuum leak somewhere.

[BADCLOWN]

there we go........so they are lean codes.


A. vacuum
B. o2 sensors
C. CCV


do you know when the CCV was last done if at all? i just bought my 2nd ZHP recently (1 owner from NC with 89k miles) and the first freezing temps here in KY a few days ago did the CCV system in. id venture to bet if you're seeing smoke mixed with the codes the CCV may be your first potential culprit.

[Scorpius]

The codes are lean codes. You probably have a vacuum leak somewhere.

Yea codes are lean codes, i can check for leaks, but a leak wouldn't explain burning oil. O2 sensors are likely to get hosed eventually if car is burning oil. So guess i'll go in safe with the CCV and just replace it. As o2 and vacuums won't cause the oil burn.

[alexandre]

I'm in the same boat at ~232k. Losing about a qt/1000 miles. CCV has 50k on it and doesn't seem to have any sludge build-up from inspecting where the hoses connect. Oil pan gasket and rear main seal are seeping but VCG and OFHG are new. While seals haven't actually failed they can certainly be worn out - I just chalked up the problem to mileage and don't really bother with it. M1 0W40 top-ups and slightly shortened O2 sensor life are certainly cheaper than a valve seal job...

[Scorpius]

I'm in the same boat at ~232k. Losing about a qt/1000 miles. CCV has 50k on it and doesn't seem to have any sludge build-up from inspecting where the hoses connect. Oil pan gasket and rear main seal are seeping but VCG and OFHG are new. While seals haven't actually failed they can certainly be worn out - I just chalked up the problem to mileage and don't really bother with it. M1 0W40 top-ups and slightly shortened O2 sensor life are certainly cheaper than a valve seal job...

Sounds exactly like the examination of my car, except my CCV is at least 3-4 yrs old since i replaced it, though i'm not seeing anything in the hoses either to suggest anything. I'll proceed with the CCV, OFHG, new coils/plugs and see what happens. If that doesn't resolve it...welp...drive it till she blows I suppose.

[LivesNearCostco]

The OFHG, VCG, VANOS feed line, oil pan gasket, and rear main seal can all leak oil but normally don't cause a vacuum leak and lean codes. The intake boots, DISA, oil filler cap, and CCV hoses can cause a vacuum leak but don't normally leak oil externally (except if drain hose from CCV to dipstick tube breaks). The CCV might be the only one that can both cause a lean code and leak oil, and it can leak oil externally into the engine compartment or cause extra oil burning and blue smoke.

But you could have two issues, one causing oil leak and other causing lean codes.

When I got my car the VCG, VANOS line, and OFHG were all leaking and after fixing them oil consumption was pretty low. Then my oil pan gasket started leaking, and I suspect the OFHG has started leaking again, 3 years and 50,000 miles after I replaced it.

[Scorpius]

So got my new CCV, I noticed there doesn't seem to be any diaphragm in this part, blow on any of the three holes and air will come out of the others. I take it this is ok?

About to start this job, still debating on going the route from the right of the engine vs. just going straight up front and replacing my OFH gasket (not needed) but looks like it's easier to do this from there. (at least as I recall) would hate to do that and find it isn't :-/