Looking to cure my endless oil consumption. M54 with likely worn or sticky oil control rings, 103k miles. Already rebuilt and swapped an M56 valve cover. No luck. Considering reverting to the stock cold climate CCV with the 02Pilot mod since an engine rebuild isn't feasible right now and likely won't be for a few years. There's some speculation as to whether extra negative pressure in the crankcase would suck seals in and cause a tricky to find vacuum leak. I've replaced all the gaskets (front and rear main, oil pan, oil filter housing, valve cover, etc...) on the motor, but I don't want to play chicken with them. Looking to get some feedback from everybody; how long have you ran the 02Pilot mod and have you encountered or heard of any negative impacts from using it long term? I'd imagine there should be no problems, since other manufacturers install only a PCV valve on their engines and put their crankcase under negative pressure.
BerdinaTheBMW
Long Term 02Pilot Mod Effects
I went beyond the O2pilot mod and did the Bavarian pcv mod 11k miles ago. Oil consumption dropped from a quart every 600-700 miles to a quart every 3500-4000 miles.
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I did the Bavarian pcv mod at least 21k miles ago and I have never looked back. I lose almost no oil between oil changes, maybe 1/2-1/4 of a quart, if that. I did this on my second e46 back in March pre-covid. It has not been driven enough, but no oil consumption since March with only about 3k of driving.
I highly recommend this Bavarian mod. I did use a "T" and route vacuum to both ends of the air distribution structure on both of my e46s.
Make sure all the clamps are tight all the way around. Check them the first couple weeks after installation to make sure they are set.
I highly recommend this Bavarian mod. I did use a "T" and route vacuum to both ends of the air distribution structure on both of my e46s.
Make sure all the clamps are tight all the way around. Check them the first couple weeks after installation to make sure they are set.
I think both the O2Pilot mod and the "Bavarian" mod accomplish the same thing. They increase vacuum in the crankcase. That's the quick and dirty way to get the low tension piston rings to seal better on deceleration.
After 5k plus miles on an e46 m54B25 with Bavarian Mod, no leaks whatsoever.
An E53 for 2 years and about 20k miles now and another E46 M54B25 for 2 years as well with 30K miles on the O2pilot mod, no leaks. As for this O2pilot mod, my consumption is at an acceptable half quart every 4k to 5k miles, and no leaks. So I can’t tell you or heard of anybody with a leaky pan gasket nor RMS that has been alleviated by an O2pilot mod.
In researching the bave39 mod, I came across someone who claims an RMS leak stopped after doing the bave39 mod. There has been back and forth on the bave39 mod causing a leak. I think it is all conjecture as nobody has confirmed or denied it. Nevertheless, I have reverted back to the BMW CCV with O2pilot mod since only 2 or 3 of the original Bave39 proponents have answered my questions on long term problems.
No untoward long term ill effects noted.
An E53 for 2 years and about 20k miles now and another E46 M54B25 for 2 years as well with 30K miles on the O2pilot mod, no leaks. As for this O2pilot mod, my consumption is at an acceptable half quart every 4k to 5k miles, and no leaks. So I can’t tell you or heard of anybody with a leaky pan gasket nor RMS that has been alleviated by an O2pilot mod.
In researching the bave39 mod, I came across someone who claims an RMS leak stopped after doing the bave39 mod. There has been back and forth on the bave39 mod causing a leak. I think it is all conjecture as nobody has confirmed or denied it. Nevertheless, I have reverted back to the BMW CCV with O2pilot mod since only 2 or 3 of the original Bave39 proponents have answered my questions on long term problems.
No untoward long term ill effects noted.
The O2pilot mod adds only a tiny pipe to the ccv to increase vacuum. I cannot see how a big strong rear seal could be damaged by vacuum. As for sucking in dirt at that point, wouldn’t there have to be a failure in the seal already?
Another question: why doesn’t the front seal also fail in the open exposed to more dirt?
Another question: why doesn’t the front seal also fail in the open exposed to more dirt?
It's something that can be figured out from used oil analyses. Otherwise the negative impact (aside from obvious things such as oil leaks) will remain hidden.
Straying off of the intended content of the OP's question....
In general front crank seals fail at a rate of about 1 to 4 when compared to the R Main seals. Just what it is.
If you have any seal on the cusp of leaking, any increased vacuum inside the engine would stave that off a little longer.
Something else to add into the mix of rear main seal leaks:
Cars with manual transmissions in general will have a leak from the rear main seal before it's automatic brethren does.
Why you ask?
The crankshaft "floats" with respect to it's placement fore/aft in the bottom of the engine. Controlled by the one larger main bearing, the "Thrust bearing." The thrust bearing has surfaces on both sides extending down/up to center the crankshaft in the block.
As many folks spend too much time holding the clutch pedal to the floor while waiting for a traffic light or just getting out onto that difficult road, the backside of the thrust surfaces of the thrust bearing bear the force one imparts when stepping on the clutch. Pushing in onto the clutch/pressure plate and ultimately forcing the crankshaft slightly forward into the bearing. Over time it wears out. There is a specification for it; Axial Play. One we check for on every PPI.
Back onto the wayward subject: If one has a worn thrust bearing there is more axial play (fore/aft movement of the crankshaft) and the corresponding wear mark on the back of the crankshaft.
Thrust bearing: #2 & #3 in the attachment:
Most rear mains will leak slightly sooner on a manual car vs that of one equipped with an automatic.
School's out.
In general front crank seals fail at a rate of about 1 to 4 when compared to the R Main seals. Just what it is.
If you have any seal on the cusp of leaking, any increased vacuum inside the engine would stave that off a little longer.
Something else to add into the mix of rear main seal leaks:
Cars with manual transmissions in general will have a leak from the rear main seal before it's automatic brethren does.
Why you ask?
The crankshaft "floats" with respect to it's placement fore/aft in the bottom of the engine. Controlled by the one larger main bearing, the "Thrust bearing." The thrust bearing has surfaces on both sides extending down/up to center the crankshaft in the block.
As many folks spend too much time holding the clutch pedal to the floor while waiting for a traffic light or just getting out onto that difficult road, the backside of the thrust surfaces of the thrust bearing bear the force one imparts when stepping on the clutch. Pushing in onto the clutch/pressure plate and ultimately forcing the crankshaft slightly forward into the bearing. Over time it wears out. There is a specification for it; Axial Play. One we check for on every PPI.
Back onto the wayward subject: If one has a worn thrust bearing there is more axial play (fore/aft movement of the crankshaft) and the corresponding wear mark on the back of the crankshaft.
Thrust bearing: #2 & #3 in the attachment:
RealOEM.com - Online BMW Parts Catalog
BMW parts 3' E46 330Ci Crankshaft with bearing shells
www.realoem.com
Most rear mains will leak slightly sooner on a manual car vs that of one equipped with an automatic.
School's out.
Early M54 engines suffered from a less than properly made rear main seal. At about 100k miles the seal would start sweeping and oil would get on the clutch. This would result in a “grabby” clutch during engagement. The cures were to substitute a quart if high mileage synthetic oil at each oil change and an occasional “spirited” acceleration from stop while feathering the clutch. The results were much less oil getting on the clutch and that nasty clutch smell.
The O2Pilot mod increases idle crankcase vacuum about ten-fold compared to stock when measured at idle. It still somewhat limits the vacuum though. Others that directly run larger I.D. vacuum hose from air distributor to valve cover end up with even higher vacuum. Not sure how high as it is out of the range of my vacuum gauge.
People playing with crankcase vacuum usually say they did this or that and state their engine is fine, but rarely post evidence such as used oil analyses in support. Most likely the engine is not in immediate danger due to these mods, but it is hard to assess potential long term effects (in case someone cares) without some kind of engine wear analysis...
People playing with crankcase vacuum usually say they did this or that and state their engine is fine, but rarely post evidence such as used oil analyses in support. Most likely the engine is not in immediate danger due to these mods, but it is hard to assess potential long term effects (in case someone cares) without some kind of engine wear analysis...
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