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E63 / E64 6 Series (2004 - 2010)
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  #1  
Old 09-15-2019, 10:55 AM
John Davis John Davis is offline
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Mystery oil leak

My 2006 650 has a slow oil leak; I have to add half a quart every couple of weeks or so.

Normally this wouldn't worry me (I know these cars tend to leak oil), but in late June of this year I replaced all this: engine oil pan and gasket, alternator bracket gasket, 2 oil cooler hoses, and the oil cooler O-rings.

I can't think of anything else that would account for a slow oil leak at this point, and my mechanic didn't find any other problems.

Any thoughts?
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  #2  
Old 09-15-2019, 11:24 AM
Waitingondapig Waitingondapig is offline
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No oil spots under the car that might give an indication of where? Does it puff some smoke after idling for a while...might be burning it through the PCV system due to some bad diaphragms?
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Old 09-15-2019, 11:47 AM
BabyUnicornTaco BabyUnicornTaco is offline
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How many miles are you driving every couple of weeks?


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  #4  
Old 09-15-2019, 12:48 PM
John Davis John Davis is offline
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Quote:
Originally Posted by Waitingondapig View Post
No oil spots under the car that might give an indication of where? Does it puff some smoke after idling for a while...might be burning it through the PCV system due to some bad diaphragms?
Come to think of it, yes, I think I've noticed some smoke from the exhaust after idling a bit in traffic. I haven't noticed an oil spot yet, though we have old oil spots that make new spots hard to discern. If there are any, they are from the engine area.
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Old 09-15-2019, 12:50 PM
John Davis John Davis is offline
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Originally Posted by BabyUnicornTaco View Post
How many miles are you driving every couple of weeks?


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Probably 250 miles a week, or more.
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Old 09-15-2019, 02:20 PM
HerbP HerbP is offline
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Could be signs of failing valve stems seals. The CCV valves could also do the same.
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Old 09-15-2019, 02:26 PM
John Davis John Davis is offline
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Originally Posted by HerbP View Post
Could be signs of failing valve stems seals. The CCV valves could also do the same.
I know that valve stem seals can cause puffs of smoke upon startup, but would they also explain the slow oil leak?

Edit: I just googled and found my answer about the oil leak.

Well, if it's the valve stem seals, I knew that day would come sooner or later. If that's what it is, I'd like to put off the expensive repair job for a few months, if possible. If the problem is in its infancy, how long can I put it off?
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Last edited by John Davis; 09-15-2019 at 02:31 PM.
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Old 09-15-2019, 03:10 PM
BabyUnicornTaco BabyUnicornTaco is offline
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Mystery oil leak

Quote:
Originally Posted by John Davis View Post
I know that valve stem seals can cause puffs of smoke upon startup, but would they also explain the slow oil leak?

Edit: I just googled and found my answer about the oil leak.

Well, if it's the valve stem seals, I knew that day would come sooner or later. If that's what it is, I'd like to put off the expensive repair job for a few months, if possible. If the problem is in its infancy, how long can I put it off?


The CCV system is fairly easy to inspect and will be first in line to rule out as your issue. Even after some replace the CCV diaphragms and clean some of the hoses they still can cause smoke out of your exhaust. This is because the intake is coated with oil on the inside and has to burn off. I have an N62 with original valve stem seals at 163,000 miles. No issues. Both the CCV and valve stem seals can cause oil consumption. I was down to a quart every 750 miles and now back up to 8,000 with the original valve stem seals. I cleaned the CCV system, replaced the diaphragms, and resealed the top half of the engine to get there. Left the valve stem seals untouched. If it is your valve stem seals that have failed, some people leave for months. The longer you wait the more risk you have of ruining your cats.


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Last edited by BabyUnicornTaco; 09-15-2019 at 03:11 PM.
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  #9  
Old 09-15-2019, 04:15 PM
John Davis John Davis is offline
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Quote:
Originally Posted by BabyUnicornTaco View Post
The CCV system is fairly easy to inspect and will be first in line to rule out as your issue. Even after some replace the CCV diaphragms and clean some of the hoses they still can cause smoke out of your exhaust. This is because the intake is coated with oil on the inside and has to burn off. I have an N62 with original valve stem seals at 163,000 miles. No issues. Both the CCV and valve stem seals can cause oil consumption. I was down to a quart every 750 miles and now back up to 8,000 with the original valve stem seals. I cleaned the CCV system, replaced the diaphragms, and resealed the top half of the engine to get there. Left the valve stem seals untouched. If it is your valve stem seals that have failed, some people leave for months. The longer you wait the more risk you have of ruining your cats.


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Thanks! That gives me some hope. I'll check out the CCV first.
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  #10  
Old 10-18-2019, 02:39 PM
John Davis John Davis is offline
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Update.

My mechanic said he thinks it's a valve stem seal issue, but doesn't require attention for the moment.

However, since that visit I've noticed that bluish smoke comes out of the right tailpipe on my 650 (when the car starts or has been idling in traffic), but not the left.

What's the significance of the fact that smoke comes from the right tailpipe but not the left tailpipe?

Thanks--
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  #11  
Old 10-18-2019, 03:58 PM
HerbP HerbP is offline
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Quote:
Originally Posted by John Davis View Post
Update.

My mechanic said he thinks it's a valve stem seal issue, but doesn't require attention for the moment.

However, since that visit I've noticed that bluish smoke comes out of the right tailpipe on my 650 (when the car starts or has been idling in traffic), but not the left.

What's the significance of the fact that smoke comes from the right tailpipe but not the left tailpipe?

Thanks--
The right side might have more wear for some reason, but that is just a guess. If the smoke gets worse, bump up to a straight 40w oil to slow it down, I read somewhere the other day that the Synthetic/mineral oil blend works better with the valve seals. This is the 1st time I have heard this, so I don't know if it is true. Changing to a high mileage oil will also help since it has additives in the oil to help keep the rubber seals from failing faster. Mobil1 makes this in a synthetic called High Mileage oil. This can be purchased in most any weight, but it does not meet the BMW spec. I have been running this foe around a year now, with no problems.
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  #12  
Old 10-18-2019, 04:08 PM
John Davis John Davis is offline
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Quote:
Originally Posted by HerbP View Post
The right side might have more wear for some reason, but that is just a guess. If the smoke gets worse, bump up to a straight 40w oil to slow it down, I read somewhere the other day that the Synthetic/mineral oil blend works better with the valve seals. This is the 1st time I have heard this, so I don't know if it is true. Changing to a high mileage oil will also help since it has additives in the oil to help keep the rubber seals from failing faster. Mobil1 makes this in a synthetic called High Mileage oil. This can be purchased in most any weight, but it does not meet the BMW spec. I have been running this foe around a year now, with no problems.
Thanks, Herb, I'll give that a try.
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Old 10-18-2019, 04:15 PM
BabyUnicornTaco BabyUnicornTaco is offline
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Mystery oil leak

Iím not usually one to recommend snake oils but as long as you donít expect it to be a solution, ATP AT-205 is supposed to be a conditioner of seals and is not supposed to swell seals. It has helped some people. I think my Original VSS just blew at 165,000 miles. Iíll be replacing myself with the help of AGA valve stem seal tools once I verify.


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  #14  
Old 10-24-2019, 12:20 PM
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Mulchman Mulchman is offline
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So replace both CCV's. One on the left valve cover, the other in the vacuum hose that connects both valve covers to the intake.

Then replace the o-ring for the aux vacuum pump located on the front of the engine, right hand side. While their replace the oil pressure switch directly under the pump. These are the two most common leaks on the N62. I have these part coming from ebay now, it will be the third or fourth time I have replaced them on my 6. 2007 w/ 165k. Look at the two VVT solenoid plugs on the right front of the motor; Are they coated in oil? Or below the pump? I would put money on it. Good luck
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Old 10-29-2019, 10:36 AM
oRIDDLERo oRIDDLERo is offline
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155k 2006 650 here. Running 10w40 Mobil one High Mileage oil for years (add 1.5 bottles of at-205). Change vacuum pump seals, both the seal to the block and the internal seal... use the good ones or you will be back again in 2 years (ask me how i know). The second time i used these double walled babd boys -- https://www.ebay.com/itm/RKX-PREMIUM...72.m2749.l2649 , Check for leaks @ alternator mounting bracket gasket, valve cover gaskets, upper timing chain gaskets, CCV diaphragms . My valve stem seals seem fine (no smoke).

I still consume some oil (around 1qt per 5000 miles), but no drips and no visible smoke. I highly recommend AT205 and upping your viscosity to 40w oil to help.
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