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
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.
There are several different ways silicon can get into the engine oil.
- Remnant of silicone-based adhesives or gasket makers, commonly applied on valve cover gaskets, oil pan gaskets, used to lube O-rings etc. These are mostly harmless (unless they clog an oil passage) and will not cause engine wear, so the UOA should indicate increased Si, but not increased metal content.
- Originating from dust that got sucked into the air intake due to vacuum leaks or a compromised air filter. Some of it will make it past the piston rings and into the oil. These particles will be too small to be caught by the oil filter and will keep circulating with the oil, increasing the metal wear. UOA will show some Si and higher than desired metals in the oil.
- Originating from dust and dirt, which made its way into the crankcase through engine gaskets and seals. Similar to the situation above, except a lot more dirt can potentially get into the oil, therefore expect higher Si and metal content. This is the scenario where increased crankcase vacuum mods could have a negative impact. I guess this may preferentially affect cars that regularly have to do long downhill stretches, where the engine runs at decent RPMs with fully closed throttle valve. This will create a high vacuum for the duration of the downhill ride. Engines with old gaskets and tired seals may be affected worse than newer and maintained ones.
- Silicon may also come from HOAT coolants such as ours, in case of a head gasket leak, but this will be very obvious as the engine probably will not run properly, and the UOA will show high antifreeze in the oil, which otherwise is below the detection limit.
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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