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Discussion Starter #1
I had to pull both VANOS solenoid boards to yet again solder a broken joint on one of the boards. I've had to do this several times before; the first time I swapped original rings on both boards to Dr. Vanos rings. One of the subsequent times that I had to pull the driver side board, I replaced the Dr. Vanos rings with OEM rings. This time I replaced the Dr. Vanos rings on the passenger-side board with OEM rings.

I used to have consumption of a liter per 500-700 miles. Now the car drinks a liter every 250-300 miles. Needless to say I'm quite upset by this turn of events.

I'm thinking of pulling the boards again and replacing all 16 rings again, but, frankly I'm pretty surprised that the consumption increased so much, and I don't know whether this would help. What could be the problem this time around?
 

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I don't see where the oil would be going if the solenoid o-rings are bad.
 

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With that rate of consumption you should either have a significant leak or black plumes coming out the back because it's burning so much
 

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If the orings were bad you would see the oil outside. If they leaked on the inside it goes back to the pan. Maybe with the correct rings in, the valves are in the correct position and you are building better compression and causing more blow by.
 

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Discussion Starter #5
I got valve cover gaskets done recently and looked over the engine for leaks, so the consumption should have improved, if anything. What really gets me is that I've pulled these boards several times and consumption was always about 500-700. Now it pretty much doubled after the last time I installed them. And postings on this board indicate that replacing O-rings improves consumption... Just frustrated at going through a liter of TWS faster than a tank of gas.
 

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Have you ruled-out oil separators, weeping grommets, rear main seal, leaking drain plug, or merely being late in the oil change interval?
 

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Discussion Starter #7
Weeping grommets were replaced along with the gaskets — another reason why I was expecting an improvement. Separator hoses have been replaced; as to the separators themselves, I cleaned them some time ago but will take another look. As to the rest, I don't notice any other leaks…
 

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If the orings were bad you would see the oil outside. If they leaked on the inside it goes back to the pan. Maybe with the correct rings in, the valves are in the correct position and you are building better compression and causing more blow by.
^^^Agreed!

I just did the exact same work you did. I had a driver's side vanos leak, replaced o-rings, and replaced valve covers as they were leaking a bit too. My car consumed a decent amount of oil before. (not sure of numbers but i think pretty standard for a MY2000).

After replacement, I have no oil leaks...they were VERY obvious before. Like you, I have burned through oil since then. I am, again, not 100% on the numbers, but it was far higher than before. I blew through a quart on a 400 mile roadtrip. The last quart I went through felt like 200 miles.

How long has it been since the jobs were done? I would just monitor and give it time. If you don't have oil leaks and the car is running fine, no need to fret about the consumption right away. The initial VANOS design was faulty. But, in it's faulty design, higher consumption could mean it is operating more effectively....which is maybe what Sailor was getting at.

I am starting to monitor mine and will keep track for you and post back here.
 

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For good measure please check the Air Intake Tracts and Air Filter Housings for evidence of engine oil !
 

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Do you have the earlier VANOS covers without the clamping screws for the solenoids? If you do, then you need to do the mod to drill and tap for clamping screws or buy the newer style covers. Otherwise the solenoids can vibrate so much they fatigue the soldered joints.

The only way solenoid o-rings can cause oil burning is if the smaller o-rings on one or both of the two outlet solenoids on bank 2 (the top two) leak so badly the leakage overwhelms the drain to the sump and oil backs up into the intake plenum and gets sucked into the engine. As suggested, pull the intake tube off and look for fresh oil in the plenum.
 

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Just triggered my check oil level warning after 340 miles and 1 quart....
 

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Discussion Starter #12
Thanks all for the replies — I'm going to pull the plenum this weekend and see how much oil is in there. I'm also thinking of cleaning the oil separators to see if that improves things. Otherwise I suppose I'll just have to get used to this rate of oil consumption!
 

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Often new valve gaskets go in but are not quite right and slip after a week or two of vacuum load. You would not be the first to have the oil consumption go up a week or two after install. Might be worth check that with an air leak test. Unplug MAFs remove in take tubes and start car next slide a piece of very stiff cardboard over the intake holes and see how long the car breaths with closed intakes. Should be zero seconds but if you have leaks into the crankcase then it will breath longer. It is a test that only lets you know if you need to do further tests.
 

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Thanks all for the replies — I'm going to pull the plenum this weekend and see how much oil is in there. I'm also thinking of cleaning the oil separators to see if that improves things. Otherwise I suppose I'll just have to get used to this rate of oil consumption!
Don't get used to the rate. It's not normal. It is annoying as **** though. Check around the oil pan for any oil. Are your newly installed valve covers sweating at all?

I am trying to sort mine out, but I just don't know where it is coming from. I am swapping out all (except lower return hoses) of the oil separator components tomorrow. I will let you know if that makes an improvement...but if they aren't leaking, there is just no way it will make a difference IMO.

And, as many others have said before. Just because your plenum doesn't have oil in it, doesn't mean oil isn't getting into the plenum and intakes. It is just getting sucked in and burned off. My plenum is clean as a whistle, but I am pretty sure I am ingesting oil, throwing my CAT codes (b2, b3)

-Brian
 

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Often new valve gaskets go in but are not quite right and slip after a week or two of vacuum load. You would not be the first to have the oil consumption go up a week or two after install. Might be worth check that with an air leak test. Unplug MAFs remove in take tubes and start car next slide a piece of very stiff cardboard over the intake holes and see how long the car breaths with closed intakes. Should be zero seconds but if you have leaks into the crankcase then it will breath longer. It is a test that only lets you know if you need to do further tests.
Sailor, I thought I remembered somebody mentioning something else that needed to be plugged up when doing this test...to avoid sucking oil back up into the plenum maybe?

Do you know what I am talking about?
 

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Yes you need to pinch off the three oil return lines.
Just to clarify; Two to the separators and the third is the very small stiff hose coming out of the bottom front of the plenum?

I can't remember, but I think the larger hose coming out of the bottom front is to the IACV?
 

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If the orings were bad you would see the oil outside. If they leaked on the inside it goes back to the pan. Maybe with the correct rings in, the valves are in the correct position and you are building better compression and causing more blow by.
If the seals arnt on correct it can cause the VANOS solenoids not to activate correctly and push oil into the intake. Im fighting this problem now, however mine is severe. OP have you removed your intake lid to see if you have oil inside it? Id just see if maybe the oil is getting pushed up into the intake and then burning off.
 
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