N52 occasional white smoke under acceleration

[ewrjontan]

So I just recently bought my 2010 e91 328i (xdrive). Has 105000 miles and on my 8 hour drive home from the dealership, the car was suffering constant power loss and engine studdering if I revved past 3000 rpm. Long story short, got it home and turned out to be eccentric shaft issues.

Took care of that. Replaced the valve cover gasket, eccentric shaft sensor and gasket, greased my valvetronic motor, replaced the valvetronic motor gasket, all new ignition coils, spark plugs were new from the dealer, replaced the water pump and thermostat, transfer case fluid, transmission and front/rear differential fluid. Reset all of the adaptations as well.

Car seems to run fine however, occasionally I get a plume of white smoke randomly and only when I am accelerating harder than normal or taking off from a stop. Super inconsistent though.

I get a service engine light soon dash light. Not necessarily after I see the smoke. Usually takes 20 or so miles of driving before seeing it. The only code I get is 2D06 (DME; Air mass system) scanned with my foxwell nt510 elite. One time the light popped up and I received no bmw codes but was able to pull a code using the obd setting. The code was p00bc (Mass or volume air flow 'A' circuit range/performance air flow too low).

I’ve been monitoring coolant levels (which I possibly had too much as I basically maxed the bob out. So the two dots on the coolant level were both higher than the cap). Seems fine.

Checked for vacuum on my oil cap; lifts off easily with little to no suction and no milky residue.

Ran a block leak tester (attach to coolant expansion tank and check for exhaust gases in fluid); nothing. No change in fluid color at all.

Cleaned my maf, checked for leaks in the air box seems fine.

Any ideas? I didn’t snap my crank case hose during the reinstallation so I think that’s fine. Thanks.

[drewusmaximus]

If it occurs when driving hard, which there's higher pressure during heavy load, then I can only assume there's a hairline crack in the head gasket. Not big enough for the oil or the coolant to reach each other, but just enough for coolant to seep though during high pressure. If you get the opportunity to smell the smoke and if it smells sweet, it's coolant.

[ewrjontan]

Hmm, is there any other way to test this? Other than having my girlfriend tail behind me until I can get a big plume of smoke in front of her?

[ewrjontan]

On the way home I got the car to smoke by accelerating to passed 4000 rpm. Tried a few times after that with nothing. When I got home I parked and gave it a good rev to try and get it to smoke which was successful. Nice cloud. Gave it several good huffs. Can’t say exactly what it smelled like. Definitely an exhaust smell with a little burning but I can’t say it smelled sweet.

When I replaced the valve cover I only replaced the gasket and not the cover like I should have. It could be leaking or perhaps the built-in pcv diaphragm is shot? Would that sort of thing cause this smoking?

[drewusmaximus]

If it's burning oil, the smoke is blue. If the smoke is black, it's running very rich. If the smoke is white, it's coolant. If the CCV is shot, you would normally see poofs of blue smoke, because the oil would travel through the intake into the combustion chamber and get burned, thus the smoke being Blue. You can pull the intake boot and look inside for oil. In my case, I can pull the DISA valve and look inside the intake. You can pull the spark plugs out and look at each piston heads to see how they look. If one of them look super clean, then that cylinder has the coolant leak, because the coolant has cleaned up the carbon in that cylinder. Keep us updated. I hope it isn't a fine crack in the head gasket. Obviously you can still drive the car without issue, as long as you don't drive it hard, but who doesn't drive a BMW hard.. LOL

[ewrjontan]

If it's burning oil, the smoke is blue. If the smoke is black, it's running very rich. If the smoke is white, it's coolant. If the CCV is shot, you would normally see poofs of blue smoke, because the oil would travel through the intake into the combustion chamber and get burned, thus the smoke being Blue. You can pull the intake boot and look inside for oil. In my case, I can pull the DISA valve and look inside the intake. You can pull the spark plugs out and look at each piston heads to see how they look. If one of them look super clean, then that cylinder has the coolant leak, because the coolant has cleaned up the carbon in that cylinder. Keep us updated. I hope it isn't a fine crack in the head gasket. Obviously you can still drive the car without issue, as long as you don't drive it hard, but who doesn't drive a BMW hard.. LOL

Right, being worried to even floor it on the interstate and what not makes driving nowhere near as enjoyable. I am hoping it is just simply my re-used valve cover leaking. I don't understand my MAF sensor code though. I feel like I am at least burning oil though because I just had to add a quart. I checked my oil level last Sunday and was sitting at about 2/3 of the oil level on my dash (non i-drive car) between the minimum and maximum levels. I had to add a quart yesterday morning. Seems like a lot of oil to lose in just a few days and I don't see any leaks under the car. I will be pulling the cowl and plugs off this weekend to check.

[drewusmaximus]

Right, being worried to even floor it on the interstate and what not makes driving nowhere near as enjoyable. I am hoping it is just simply my re-used valve cover leaking. I don't understand my MAF sensor code though. I feel like I am at least burning oil though because I just had to add a quart. I checked my oil level last Sunday and was sitting at about 2/3 of the oil level on my dash (non i-drive car) between the minimum and maximum levels. I had to add a quart yesterday morning. Seems like a lot of oil to lose in just a few days and I don't see any leaks under the car. I will be pulling the cowl and plugs off this weekend to check.

I have the non i drive model too. I hate the no dipstick. I changed the oil a month ago and I added 6.9 Qts, exactly what the manual recommended, but the oil level was at 3/4 between the min and max lines. I ended up adding a total of 7.3 Qts and the full bar reached the max line. When I got the car, the full bar was past the max line, which means the PO put too much oil. Thankfully I always change the oil as soon as I purchase a used car.
What's wrong with the MAF?

[ewrjontan]

Yeah it was basically somewhere between 2/3 and 3/4 of the min/max markings. As for the maf:

I get a service engine light soon dash light. Not necessarily after I see the smoke. Usually takes 20 or so miles of driving before seeing it. The only code I get is 2D06 (DME; Air mass system) scanned with my foxwell nt510 elite. One time the light popped up and I received no bmw codes but was able to pull a code using the obd setting. The code was p00bc (Mass or volume air flow 'A' circuit range/performance air flow too low).

[drewusmaximus]

When you replaced the VCG, did you properly unwind and wind the eccentric shaft to its proper position? If the eccentric shaft isn't performing its job, oil can pass through to the combustion chamber and can cause vacuum issues, in which affects the MAF.

[drewusmaximus]

https://www.youtube.com/watch?v=odN6KVue_J0

Most likely it's your CCV. The oil burning smoke does look white but has a light hint of blue. Coolant is just white. And if the smoke doesn't smell sweet, then it's oil. It's just not burning so much oil at once, which is why it looks white with a very light hint of blue. If it were burning mostly oil, the smoke would be blue. You can replace the CCV or go the CC route. The problem with the CC route is, it has to be a precise setup because vacuum is key with that setup. Too much vacuum or not enough vacuum can occur if you don't have the precise setup. An Ebay catch can will not cut it and you have to find the correct check valve to perfectly control the vacuum. If you replace the CCV, go OEM. Those 30.00 CCVs from China will last a couple of months. When my CCV goes bad, I'm going with an OEM CCV. I tried the catch can method on my e46 and it was a nightmare. Too much vacuum, had to close off the dip stick hole. Had to buy several check valves to control the right amount of vacuum. It was a mess. I feel it's easier to replace the CCV. If I add more power to the car, then I'll revisit the CC method.

[ewrjontan]

I did, or at least I believe I did. During removal I turned the valvetronic motor clockwise (towards the front of the car) into "service mode" then loosened my bolts. Then turned it counter clockwise to push the motor out. During reinstallation, I put the motor in, turned it back clockwise to service mode to "pull it in", tightened the bolts and turned it all the way counter clockwise until I felt tension. Turned the car on (not engine) for a couple minutes to let it relearn the motor limits. Did that another time and also recalibrated the limits using my Foxwell scan tool. I do see a little bit of oil on one of the valve cover screws that holds the mounting bracket for the motor but I am also not sure if it's just residue from dirty screws or the bracket. Could also be the motor gasket did not seat correctly. Again, will check this weekend.

I do feel like I notice a sort of light blueish tint to it when I blow the smoke, and look in my rear view mirror (while driving). It was kind of hard to tell when I sniffed it yesterday as it was already dark. What sucks is that my ccv is attached to the valve cover since I have the plastic one so it sounds like this might be the best route.

[drewusmaximus]

I did, or at least I believe I did. During removal I turned the valvetronic motor clockwise (towards the front of the car) into "service mode" then loosened my bolts. Then turned it counter clockwise to push the motor out. During reinstallation, I put the motor in, turned it back clockwise to service mode to "pull it in", tightened the bolts and turned it all the way counter clockwise until I felt tension. Turned the car on (not engine) for a couple minutes to let it relearn the motor limits. Did that another time and also recalibrated the limits using my Foxwell scan tool. I do see a little bit of oil on one of the valve cover screws that holds the mounting bracket for the motor but I am also not sure if it's just residue from dirty screws or the bracket. Could also be the motor gasket did not seat correctly. Again, will check this weekend.

I do feel like I notice a sort of light blueish tint to it when I blow the smoke, and look in my rear view mirror (while driving). It was kind of hard to tell when I sniffed it yesterday as it was already dark. What sucks is that my ccv is attached to the valve cover since I have the plastic one so it sounds like this might be the best route.

I'm confident it's not the coolant. I strongly believe it's the CCV. If the CCV is original, I would replace it anyway, just for sanity and not have to worry about it for a long while. The CCV hose that connects to the back of the VC is a pain and can easily fracture. I bet that hose causes a ton of issues. I haven't replaced mine yet, but I think when it's time for me to replace the VCG, I might as well replace the CCV at the same time. Keep us posted. I'm looking forward to a happy ending.

[ewrjontan]

Yeah, I was able to get the ccv hose from the back off with no issues. Probably helped that right before I got the car they replaced the vcg but I had to do it again since I had eccentric valve sensor issues. I have an extra hose but I don't believe it is cracked. It can be replaced without removing the intake manifold right? Just pull the alternator out of the way?

[drewusmaximus]

Yeah, I was able to get the ccv hose from the back off with no issues. Probably helped that right before I got the car they replaced the vcg but I had to do it again since I had eccentric valve sensor issues. I have an extra hose but I don't believe it is cracked. It can be replaced without removing the intake manifold right? Just pull the alternator out of the way?

You can try, but I would replace the whole CCV unit, not just the hose. It's the CCV's diaphragm that's failing. I'm not sure if you can remove the CCV unit while the intake is still in place. If you do, please let us know how you did it.

[ewrjontan]

Just to make sure, I have a 2010 LCI N52 so if I am correct, the CCV is built into the valve cover. Not sure where the other end of the crank case vent hose (which attaches to the valve cover) goes but on older n52's that hose connects to the ccv stuff under the intake manifold. I think in my case I can try and pry off the CCV and replace it but it is probably a better idea to just replace the whole valve cover.

I just got back from a drive and my oil level is already lower than when I filled yesterday morning. I was at 3/4 (between min and max) when I checked yesterday evening around 5pm and now I am at 1/2 between min and max. Haven't driven anywhere in between, all I did was rev a few times to get some smoke. I don't believe there are any leaks under the car but there are so many panels underneath.

[ewrjontan]

Alright, so I actually was able to pull some stuff apart today. Removed the engine cover and found the valvetronic motor gasket is leaking. Pooling of oil and the only around the perimeter of the valve cover are the two where the motor bracket sits; it is on top of the bracket mounting holes/bolts but the side is dry. I am assuming the oil is pooling between the valvecover and the bracket and working its way to the bolt heads.

Anyways, definitely going to fix that. Not sure if its cracked or not and if I might have to use some RTV around the gasket. I did a rescan of the car though and I have several misfire codes now.

29CC - DME: Combustion misfires, several cylinders.
29D0 - DME Combustion misfires, cylinder 4
29D1 - DME - combustion misfires, cylinder 5
29D2 - DME Combustion misfires, cylinder 6
29E0 - DME Mixture control
29E1 - DME Mixture control 2
2D06 - DME: Air-mass system
2D15 - DME: Air mass sensor measurement range

Would the leaking gasket cause all of these issues? Perhaps the CCV is also crapping out? I tried removing the oil cap when the engine was running a few days ago and I had zero vacuum. It lifted off no differently then when I would do it with the car off. Is this a sign that the CCV is also bad? I want to just replace the valvetronic motor gasket but I also don't want to buy one, just to end up buying a new valvecover and doing this all over again. I also noticed oil around my oil cap, so not sure if that is just drips from me taking the cap on and off or if it too is leaking. Plugs and ignition coils are brand spanking new.

I ended up pulling the spark plugs and they have a lot of carbon build up on them and also oil on the threads; every plug. It's not "soaked" and dripping in oil but there is defintitely oil on the threads; could be from not cleaning the threads out I guess. However, the spark plug wells, my ignition coil boots, and even the spark plug gaskets all are completely dry as far as I can tell. What does this mean? Still a possible CCV issue? I am hesitant to replace the valve cover now as it seems like the actual gasket itself as well as the spark plug tubes seem fine. The valvetronic motor gasket is obviously an issue but I don't feel like it would lead to oil on the threads of the plugs. Anyways, here are some pictures.

Edit: posting images on this forum is just terrible. img tags don't work, attachments don't work. Screw it. Here's a link to the album.

https://imgur.com/a/jvoHJWx

[drewusmaximus]

It sounds like it's leaning to the CCV. I would replace it while you have things apart. Then you don't have to worry about it for a long while. I would definitely buy an OEM CCV unit with the hose.

[ewrjontan]

Yeah, I spent a few hours contemplating if I should just order the valvetronic motor gasket and try it; who knows maybe that solves it for $30. But then I figured if the CCV wasn't already damaged, it has 105,000 miles on it already so I'd probably end up replacing it in a few months anyways. So I went ahead and ordered a whole new valve cover as well as some new NGK plugs since mine are super fouled up; unfortunate since they are less than 1000 miles old.

After researching more on the vvt motor gasket, I am starting to wonder if it may be worth throwing some RTV on there. Sounds like everyone has problems with this gasket but I can't seem to find if they are using BMW gaskets or some other aftermarket oem brand and also if they are using aftermarket or genuine valvecovers. I feel like I shouldnt need to use the RTV but I don't want to deal with this stupid valve cover anymore at this point. I have driven the car less than 1000 miles in my ownership and have already done more work than other cars that I have owned for longer.

Edit: wow so I just realized that my current valve cover isn't the original. The dealership that I purchased the car from must have replaced it all when they did the gasket. Turns out it is a Dorman valve cover. I found a few reviews (all poorly rated) and one of them mentioned that the distance to the valvetronic motor is bigger than it should be which is why my gasket ripped; the reviewer said they ripped three of them.

I guess it's a good thing I bit the bullet and just went and ordered a BMW one because I definitely would have ripped the next valvetronic motor gasket and been super pissed. However, this leads to a new problem. The CCV SHOULD be fine at this point since it is a new cover. Now I am worried. No turning back now though since I was examining the CCV puck and ended up snapping the nipple off of it with little to no force. So who knows, maybe the CCV was crap.