What’s up everyone. I’m looking for a bit of confirmation before I go down the valve stem guide seal replacement hole. I’ll start at the beginning…

2010 R56 MCS, 77k miles with full bolt-ons, K03 42MM, and stage 2/3 exhaust manifold from JMTC. After all mods were done (car was 100% stock before) the car was then catless. I noticed a fair amount of smoke on initial throttle input ONLY after 10+ seconds of idling. No smoke on start up. I replaced PCV, but the issue was still present.

During the next oil change, I noticed a fair amount of fuel in the oil (the oil smelled heavily of fuel and was milky). I spoke to a local shop, they recommended changing the HPFP, which I did, but thought it was odd since that’s a closed system and shouldn’t be able to put fuel into the oil, correct? Could a faulty HPFP somehow be the cause of that? I was thinking faulty injector being left open?

After changing the HPFP and valve cover to replace the PCV, not only did the puff of smoke after 10+ seconds of idling persist, but now I have an epic amount of oil blow by. I mean, you could paint abstract art with the amount that comes out of this thing. So now I’m even more confused…the oil blow by is something that didn’t exist prior to changing the valve cover.

I just did a compression test, it’s about 160-170 across the board. Then I did a leak down test…the results were damn near perfect with around 5% loss on all cylinders. Does this sound like a valve stem guide seal issue?
Any help/input is appreciated!

TLDR, puff of smoke (bluish tint) only after 10+ seconds of idling. Replaced PCV. Still happens. Fuel in oil, replaced HPFP (haven’t done oil change since). After HPFP and PCV replacement, epic oil blow by. Compression and leak down are good. Car has full bolt ons, no cat.

 

Which valve cover replacement did you use? Seems that some of the cheap ones can have PCV issues out of the box.

 

Ah, interesting. I'm building this car for my brother, he ordered from ECS, but it wasn't OEM. You think that could be the cause of the blow-by or both issues?

I was hoping the new valve cover would solve the smoke after idling issue...instead I got a new issue and the puff of smoke was still there, lol!

 

I'd wager that it is indeed valve stem seals. It sounds like your symptoms are precisely what I had on my R56 when the milage was around 70k. I had to basically put oil in the car every week. I also replaced valve cover and PCV valve without success. The only thing left was valve stem seals. Once I replaced the seals the white smoke issue was resolved.

 

+1 Valve stems seals, they are very common even if you replace with a genuine valve cover and have this issue. See it all the time. If the smoke level never changed thats it.

 

Yeah, I think you're right.

Do you think that would contribute to the oil blow-by as well?

 

Heyyy, it's the parts plug! You guys are awesome!

Yeah, I think you're right. Do you think that could lead to the oil blow-by as well? It's odd that the oil blow-by didn't start until after the valve cover was replaced.

 

Yep. lol

If its happens more after it could be the cover, best way to test is to swap in an old one. I have seen some rare but stuck factory genuine mini diaphragms on the PCV. Other thing to check is that the seals could also be on their way out and this was the trigger time.

Also make sure everything was hooked up right and no issues. The puff of smoke is worst on the seals after the car sits from hot. Then first start up gets a bunch of smoke. Check the turbo hot and cold side. The colds side will have little bit of oil at the bottoms. Just to make sure the turbo seal is not bad or anything crazy.

Bad leak


https://www.northamericanmotoring.co...own-turbo.html

The turbo will have some very little oil on the inlet, but not a bunch. Its like a small smear of oil at the bottom of the cold side.

 

I just finished this journey this week. My blue smoke issue started with something unrelated, I was trying to refill the refrigerant, which takes a LONG time sitting there idling. My 2011 MCS N18 has never sat still so long and it was starting to drown in oil. After a few minutes of doing so, I would give it some gas and a huge plume of blue smoke would blast out. After that, I tested the coolant for any exhaust, luckily there was none, but this confirmed that I had to do the valve seals. Also, since you are going to be in there and going to need to take off your cams, you’ll probably going to want to go ahead and do the timing chain (it’s really more the plastic chain guides that are the problem). It WILL fail. Luckily I only had to fish out large pieces of plastic. Unfortunately this is likely mandatory service for your car in the next year or two.

Do your valve seals. It’s time. I let it idling for 30-40 minutes, again trying to refill the refrigerant, and not a puff of smoke. You know it’s time. For clarity, here is what’s going on in your engine.


New on the left, 93K miles on the right. Please also note that I drive like a wuss most days. Obviously, the one on the right ain’t gonna be snug around the valve stem, so oil is going to just pour right down the stems.