Smoking When Coming To a Stop -- An N54 Owner's Right of Passage

[chadillac2000]

Starting about two weeks ago, I started to get a bit of smoke coming out of the exhaust. This only happened when the car had reached full operating water/oil temps, had been sitting in stop-go traffic, when riding 2nd gear to a stop, and when the RPMs dipped below 1000. Smoke clouds of varying sizes, depending on conditions, would envelop the car. I initially thought it may have been a faulty flapper valve, which is why I replaced that a few weeks back. The clips had been compromised and the o-ring didn't seem to be sealing any longer. That cheap fix did not correct the smoking when coming to a complete stop.



I re-checked all the connections to the oil catch cans and verified all hoses were in the proper places. The external PCV eliminated the possibility that my PCV valve had failed. I have a BMS OCC on the high side, and the RB external PCV connected to a Mishimoto OCC on the low side.







Barring catastrophic damage, which would be unexpected as the car is running phenomenal otherwise, this left only two things that could be causing this: valve cover issues or leaking turbo seals. Injectors had been replaced with Index 12s recently and plugs were good. I removed the engine cover and inspected the valve cover for any leaks. While there didn't seem to be any obvious areas, there were some damp spots. As I'm quickly approaching 80,000 miles and over 8 years on the OEM valve cover and gasket, it's certainly a candidate for failure. At nearly $400.00 for the cover, gasket and bolts, its not a scheduled maintenance item I'd budgeted for.

At some point of my forum research for a solution to this smoke, I read about a test that involved holding the throttle around 1000-1200RPM for an extended period. To my amazement, after doing this for a bit I started seeing more smoke than ever before. I grabbed my camera and filmed this. Keep in mind that the car is fully warmed up. It will not smoke AT ALL if not fully up to temperature. No smoke under boost. Just when it passes that threshold of 1000RPM before falling back to idle. I can avoid smoking all together by throwing the car into neutral and rolling to a stop instead, which is what I've been doing in traffic to alleviate the embarrassment.

I've already purchased a new valve cover, gasket and bolts in the hopes of stopping the smoke. Those items should be here Friday and I'll be installing them Saturday to see if this corrects the problem. I'm already prepared to see the problem immediately remedied, but if turbo seals are truly the culprit, I should see the smoke when stopping come back in a week or so. The most logical explanation in my mind seems to be that the valve cover PCV inner components are gunked up or there is a crack/compromised portion of the gasket that is causing issues when the car is transitioning from boost to vacuum.

Also not burning any oil. The oil level is still at max from the last oil change.

[1and1]

Quick reminder- are you running without kittens? The back pressure they bring to the party makes a difference to the seals...

Tho, as I recall you have new turbos in the very near future

[chadillac2000]

Originally Posted by 1and1

Quick reminder- are you running without kittens? The back pressure they bring to the party makes a difference to the seals...

That seems to be a common thought on the forums, but I've been running fully catless for 15,000 miles with no smoke at all so not sure how much stock I put into that. This started a few weeks ago out of nowhere.

Originally Posted by 1and1

Tho, as I recall you have new turbos in the very near future

Why yes I do sir!

[chadillac2000]

Earlier today I was able to spend some more time with my 1er trying to track down the cause of the recent smoking issue I've been having. I wasn't 100% convinced it was a valve cover problem, but at my mileage, it was probably going to break down soon anyways. I purchased a brand new valve cover from ECS Tuning and it came with brand new bolts and a brand new gasket already pressed into place. Not the most fun way to spend $379.50 on a 135i. I also picked up 6 more feet of Earl's Pro Lite 350 -6AN hose so I could run the same line instead of the mismatched hoses I had prior.





I had just done this job a few months back on my E60 535i right before I handed the keys over the new owner, so I was still somewhat familiar with the process. Started by popping the hood and then used the ECS Tuning N54 valve cover install guide as close reference.



I then removed the passenger side of the strut bar and the cosmetic engine cover.



Next to come out was the DCIs and low-side OCC hoses.



I also took this opportunity to dump the catch can after 2,000 or so miles. Incredible as usual.



As I started to remove the coil harnesses and coil themselves, I noticed that I had a pool of oil sitting near the cylinder 5/6 injectors that had not been there previously. This could indicate a crack in the the valve cover, a breakdown of the valve cover gasket or both.



The coils were the next to be removed, along with the sleeves inside.





Using the same pick I took the sleeves out with, I removed the harnesses attached to each injector as well as the small nuts on the ground posts. Two more 10mm bolts hold the entire wiring harness to the valve cover. Two other vacuum hoses must be removed from the vacuum canisters as well as right behind the oil filter housing.



Now was time to remove the fuel lines that are form-fitted over the valve cover. A 14mm wrench, a towel, and ventilation was needed.



After all the excess fuel has been soaked up by the towel, I broke open the other 5 14mm fuel lines on the driver's side. Then it was on to the injector side of the lines. A 13mm on the injector to make sure it doesn't get torqued around, and use the 14mm to break loose the nut.



I then used a long 10mm socket instead of the special BMW tool to remove the ground posts. The socket wrench doesn't completely click into place, but gives just enough depth to be able to unbolt the ground posts.





There are four 10mm bolts that hold the fuel rail to the head. These, along with the clips and harnesses, must be removed.



Now it was FINALLY time to start removing the 28 bolts securing the valve cover.



This takes patience, a strong back, a few different extensions and swivel sockets. Eventually I had them all removed. I chose to remove each of them with a pair of needle nosed pliers just to be certain that I hadn't left any partially screwed in. I pulled away all the wiring so everything would be easier to remove/install.



I then used this little trim tool to pry away the valve cover until it was freed all the way around.



I carefully pulled the old cover up and out to get my first glimpse at what lies beneath.





After cleaning off the old valve cover, I verified that there were no cracks or damaged areas. This would lead me to believe the oil was probably due to a failing valve cover gasket. The valve cover itself was in very good condition.



I chose not plug the ports on the head at this time, so I just wiped down all the contact areas and made sure they were clean.



Before I installed the new valve cover, I removed the brand new OEM PCV valve. This was replaced by the RB external PCV fitting. I also swapped over the oil cap hardware. Ensuring all of the wires and hoses were pulled away, I lowered the new valve cover into place. Already having the bolts and gasket in place from the package was very useful.





With the bolts already pre-installed into the cover, all I had to do was simply start tightening.



After snugging them all up by hand, I then went to each of the 28 bolts and applied the recommended 75 in-lbs.



Valve cover bolts torqued down and fuel lines tightened down.



All ignition wires connected and coils installed.



These two small vacuum hoses had become hard, brittle and cracked when I removed them. Luckily I had 15 feet of high temperature vacuum hose I'd picked up for my impending turbo install, so I utilized some and replaced the compromised portions.



The last thing i wanted to address was to correct my mismatched low-side OCC hoses. Using the 6 feet of new hose, I cut the IN and OUT to fit and ran each to ensure no kinks.





This new location allows for easy emptying without removing or unbolting anything.



After the catch can connections were reinstalled, I started the car to ensure there weren't any leaks or other issues. The car took a few seconds to crank due to the lack of fuel, but fired right up and idled great. I verified there weren't any leaks or smoke before bolting down the engine cover and moving on to the cowl setup.

For a nearly a year now I've been running inlets and cowl filters. This produces an intense intake sound in the cabin under any type of moderate throttle. When running the BMS high-side OCC, trimming of the engine cover is required. This removed some of the sound deadening material, allowing the audible tick of the direct injectors to be heard easily.

Looking for a change of pace, I went back with the OEM cowl setup and cabin filter. The BMS high-side OCC is hidden beneath the cowl setup now and the Mishimoto low-side OCC is still easily accessible. The black DME lid and brake fluid reservoir blend right in.



Before starting the car up and backing it out of the garage, I threw on a new oil bolt shield and clip. Mine was missing when I bought the car.



I've also picked up some more components in preparation for my impending turbo upgrade. These include a new 335is clutch kit, new v-band clamps, new downpipe gaskets, a new rear main seal, a new oil pan gasket and bolts.



After rowing through the gears a few times, there was certainly a pleasant decrease in cabin noise with the OEM cabin filters in place as well as outside with an extra few layers of plastic separating the direct injectors from ears.

On the drive home I got the car up to temperature and stopped at a few lights with no signs of smoking. When I backed up into my driveway, I repeated the 1000RPM test that used to produce clouds of smoke before and could not get that to happen. I'm still skeptical that the valve cover has fixed my smoking issue, but nevertheless, I'm glad it's been replaced along with the gasket for maintenance reasons. Within a few thousand miles or so, that oil leak would have found its way into the spark plug galley and more than likely started causing misfires. Keeping the oil inside an N54 is a constant struggle.

[1and1]

Sweet! Glad to hear the smoking symptom appears to be resolved!

Really need to do a DIY out of this vc replacement... Even if it's only a link to this post.

[Havocsteve]

I assume it would be the same process for the N55? This is a great write-up for the VC replacement. I second 1and1!

[chadillac2000]

Originally Posted by 1and1

Sweet! Glad to hear the smoking symptom appears to be resolved!

Really need to do a DIY out of this vc replacement... Even if it's only a link to this post.

Seems it was wishful thinking!

Morning update: replacing the valve cover and valve cover gasket did not cure the smoking when coming to a stop issue I was having. Seems like a given at this point this is an example of leaking turbo seals.

Originally Posted by Havocsteve

I assume it would be the same process for the N55? This is a great write-up for the VC replacement. I second 1and1!

I might put one together here shortly and add it to the DIY section.

[1and1]

It does take a while for the seals to wear to the point of seeping enough to let the smoke at idle symptom appear. Sadly, once it starts you either rebuild or replace and replacing with better is really the only good fix- darn handy you've got a baller set waiting for you!

You could try to stave off the issue a bit with some thicker oil, but....

Yeah, so, take lots of pics when you... (insert a sexy twins joke here)

[chadillac2000]

Originally Posted by 1and1

It does take a while for the seals to wear to the point of seeping enough to let the smoke at idle symptom appear. Sadly, once it starts you either rebuild or replace and replacing with better is really the only good fix- darn handy you've got a baller set waiting for you!

You could try to stave off the issue a bit with some thicker oil, but....

Yeah, so, take lots of pics when you... (insert a sexy twins joke here)

I'm sure these have been on the way out for some time now despite still performing flawlessly. The smoking did come coincidentally (or maybe not) just a few weeks after I started running the V5 E40 MHD flash that targets close to 21psi -- although I only went WOT a handful of times over a few weeks before I started noticing the smoke. Not to say that was to blame as plenty of people run 21psi on stock turbos with inlets without issue or smoke, but it very well could have been the straw that broke the camel's back.

Interestingly enough, a few thousand miles before I noticed the smoking, I also switched from OEM 5W-30 to Motul X-Cess 5W-40, so the thicker oil did not do much to stop smoking.

And not to worry on the pictures, I will be taking as many as I can (considering I'll have busted knuckles and filthy with oil/coolant more than likely). The amount of car parts porn I'll have to install at once will be very exciting.

[Jorgensen54]

Really appreciate the pic heavy VC replacement walkthrough! I'll be doing one on a friends 535i soon and this will be a huge help.

[brytom]

I've done a lot of VCGs. Never one pulled the spark plugs tubes first. They will stick in the cover or the head. Have not damaged one in almost 5 years. Save you the trouble of picking them out individually.
I always keep spare vacuum line on hand and replace the braided portion from the main vacuum hose off the pump to the pair of crossover plastic hoses. They are almost worn out by now.

[chadillac2000]

Originally Posted by brytom

I've done a lot of VCGs. Never one pulled the spark plugs tubes first. They will stick in the cover or the head. Have not damaged one in almost 5 years. Save you the trouble of picking them out individually.
I always keep spare vacuum line on hand and replace the braided portion from the main vacuum hose off the pump to the pair of crossover plastic hoses. They are almost worn out by now.

I'll have to try that next time. It's a very obnoxious part of the job, but I always just followed the ECS DIY guide which indicates you should. Next time I'll skip that step, but hopefully I won't be doing this job again for a long time to come!

Those hoses seemed to be the most brittle out of any I've come across, I had no intentions of trying to salvage those to reuse. Having done the job twice now, getting the original vacuum lines disconnected is challenging when you're also trying to break the plastic attachments.

[Aode06]

Any catless BMW, remove 1 quart of oil so your meter will show i. The middle, still safe zone, but not full zone.

Thhis will eliminate those pesky red light smoking incidents.

[AWSAWS]

Originally Posted by chadillac2000

Seems it was wishful thinking!

Morning update: replacing the valve cover and valve cover gasket did not cure the smoking when coming to a stop issue I was having. Seems like a given at this point this is an example of leaking turbo seals.



I might put one together here shortly and add it to the DIY section.

Hi,

I have the exact same symptoms.

I too have changed the valve cover, pcv and flapper.

Am suspecting valve stem seals or the China 19t turbos I installed recently.

So just wondered if you ever got to the bottom of this at the time.
My car runs great bar clouds of embarrassing oil smoke.

I do need to change the secondary oxygen sensors.

Would be great to know what was the outcome. Thanks.

[e92laith]

Originally Posted by AWSAWS

Hi,

I have the exact same symptoms.

I too have changed the valve cover, pcv and flapper.

Am suspecting valve stem seals or the China 19t turbos I installed recently.

So just wondered if you ever got to the bottom of this at the time.
My car runs great bar clouds of embarrassing oil smoke.

I do need to change the secondary oxygen sensors.

Would be great to know what was the outcome. Thanks.

Hey, i have a few questions. Going through the same thing. Can i still drive the car for a bit? Can i push it? would me throwing it in neutral every light help? I'm selling the car soon or throwing some 19ts on but like how long do you think i can drive it for? thanks boss. I have 17ts btw

[AWSAWS]

Originally Posted by e92laith

Hey, i have a few questions. Going through the same thing. Can i still drive the car for a bit? Can i push it? would me throwing it in neutral every light help? I'm selling the car soon or throwing some 19ts on but like how long do you think i can drive it for? thanks boss. I have 17ts btw

Well if its valve stem seals or turbos it'll just get worse.

Will probably kill your cats if you have them and foul oxygen sensors, etc if it's very oily. Will also coat the inlet valves in oil if it's recirculating.
Not terminal but not great.