Here is why your valve cover still "leaks" after replacing the N54 valve cover gasket

cstavaru · 07-09-2021, 05:39 AM

This problem drove me nuts after first replacing the valve cover gasket and then the next day the valve cover entirely, only to have oil profusely "leaking" on the turbochargers and raising worrying amounts of smoke from the engine bay. It drove me nuts so much so that I made it my sacred mission to solve the mystery.

The forums are full of people having "leaks" after replacing the valve cover, re-doing it, replacing the cover, re-replacing everything, etc. After all these years no one solved the mystery in a scientific way, everybody said things like "cover is cracked, cover has invisible cracks, gasket is pinched, turbos are bad, oil filter housing gasket is bad, check the rear main seal", etc.

Nonsense ! Of course, those problems can arise, but they have to be scientifically diagnosed by looking at those areas with an endoscope or other means (by the way, I highly recommend investing $30 or so in an endoscope !)

Over time some people did suggest that the heat shield is the culprit, but they thought that cleaning it with brake cleaner and pressure-washing it is enough. This created an even worse problem: people have a clean and shiny heat shield that pools oil so they think: "now that the shield is clean and there is still oil pooling and smoke, I surely messed up the valve cover replacement or the cover is cracked or whatever".

Nothing farther from the truth ! Look at the heat shield in the video: it is fully cleaned with brake cleaner and then pressure washed. As you can see, those methods have no effect whatsoever.

My advice: when replacing the valve cover gasket, it is mandatory to remove the turbo heat shield (it is nothing compared to the other parts of the valve cover job) and heat it on a gas stove and remove all oil that comes up. Using a blow torch would probably work too but it can cause cosmetical damage if held too close to the shield.

You're welcome !

NoGuru · 07-09-2021, 07:09 AM

Or you could just simply clean it with some brake cleaner. I see no science behind your method at all other then saying "this worked for me so it will work for everyone".

tcphoto · 07-09-2021, 07:46 AM

I guess that's one way of doing it...

cstavaru · 07-09-2021, 08:16 AM

Quote:

Originally Posted by NoGuru

Or you could just simply clean it with some brake cleaner. I see no science behind your method at all other then saying "this worked for me so it will work for everyone".

Please note, the heat shield was already cleaned and pressure washed (and confirmed to still create oil pool when on the car!) when putting it on the gas stove ! The cleaner has no effect since the shield is made of two thin sheets of metal sandwiched together, and oil is in-between. And I am not referring to the shield and its holder bracket, but the entire shield is double-walled.

mapleleaf1773 · 07-09-2021, 10:35 AM

It would burn off after just a couple trips if oil was stuck in the middle of those thin metal sheets - no big deal. Its more of a pain to get those pesky bolts back in after everything is put back together. Just my experience.

OP, are your oil issues resolved? If not, id check the valvetronic motor gasket on the valve cover. Over time, the valve cover plastic weakens and that gasket (the seal of the valve cover against the gasket) becomes "more flimsy" hence oil leak that pools up and runs onto that metal bracket. That can be a pain in the @$$. Just my 2 cents

cstavaru · 07-09-2021, 11:14 AM

Quote:

Originally Posted by mapleleaf1773

It would burn off after just a couple trips if oil was stuck in the middle of those thin metal sheets - no big deal. Its more of a pain to get those pesky bolts back in after everything is put back together. Just my experience.

OP, are your oil issues resolved? If not, id check the valvetronic motor gasket on the valve cover. Over time, the valve cover plastic weakens and that gasket (the seal of the valve cover against the gasket) becomes "more flimsy" hence oil leak that pools up and runs onto that metal bracket. That can be a pain in the @$$. Just my 2 cents

My oil issues are completely, fully solved

PS: The N54 engine does not have Valvetronic

mapleleaf1773 · 07-09-2021, 11:23 AM

oh ok, sorry didnt realize you had the n54

NoGuru · 07-09-2021, 11:35 AM

Quote:

Originally Posted by cstavaru

Please note, the heat shield was already cleaned and pressure washed (and confirmed to still create oil pool when on the car!) when putting it on the gas stove ! The cleaner has no effect since the shield is made of two thin sheets of metal sandwiched together, and oil is in-between. And I am not referring to the shield and its holder bracket, but the entire shield is double-walled.

Okay, this makes a little more sense.

relative4 · 07-09-2021, 01:42 PM

Quote:

Originally Posted by mapleleaf1773

oh ok, sorry didnt realize you had the n54

Yeah, it's not like it's in the title or the thread is in the N54 forum.

mapleleaf1773 · 07-09-2021, 01:47 PM

yea true but im on a cell phone and im old. so i missed it

stewbets · 07-09-2021, 02:25 PM

Quote:

Originally Posted by mapleleaf1773

yea true but im on a cell phone and im old. so i missed it

I understand

studio54 · 07-10-2021, 10:04 PM

Quote:

Originally Posted by mapleleaf1773

yea true but im on a cell phone and im old. so i missed it

kazbek1 · 11-19-2021, 11:05 AM

Hey guys, I'm having some difficulty getting the new bolts into the new valve cover. Is there a trick to sliding them in? I don't want to force them in with a mallet or use pliers to clamp them in...Any tips?

DrivingPassion · 12-02-2021, 10:14 AM

cstavaru ,

What are the steps to remove heat shields ?
I'm having the same issue: VCG was replaced recently (2 weeks ago) but I still get occasional oil dripped onto wire of the precat O2 sensor when I drive spiritedly and brake aggressively.

I have a feeling that there is a small pool of oil on the heat-shield collected somewhere in the rear and when the car is driven aggressively, that oil is spilled out to the PreCat )2 sensor wire.

I'll be inspecting the edges of the VCG and do a beneath-the-car inspection as well. Getting tired of this issue.

DrivingPassion · 12-02-2021, 10:16 AM

Quote:

Originally Posted by kazbek1

Hey guys, I'm having some difficulty getting the new bolts into the new valve cover. Is there a trick to sliding them in? I don't want to force them in with a mallet or use pliers to clamp them in...Any tips?

You do not remove those bolts entirely. You unscrew them until they are completely loose but let them sit in the cover. That's how they are designed.

kazbek1 · 12-02-2021, 12:53 PM

Quote:

Originally Posted by DrivingPassion

You do not remove those bolts entirely. You unscrew them until they are completely loose but let them sit in the cover. That's how they are designed.

Yea I knew that part but the valve cover I got had cheap feeling bolts so I wanted to use the OEM ones. I ended up using needle nose pliers and yanking them out.

DrivingPassion · 12-02-2021, 12:55 PM

Quote:

Originally Posted by kazbek1

Yea I knew that part but the valve cover I got had cheap feeling bolts so I wanted to use the OEM ones. I ended up using needle nose pliers and yanking them out.

Got it. Thanks for the clarification.

DrivingPassion · 12-02-2021, 12:59 PM

Quote:

Originally Posted by DrivingPassion

cstavaru ,

What are the steps to remove heat shields ?
I'm having the same issue: VCG was replaced recently but I still get occasional oil dripped onto wire of the precat O2 sensor when I drive spiritedly and brake aggressively.

I have a feeling that there is a small pool of oil on the heat-shield collected somewhere and when the car is driven aggressively, that oil is spilled out.

I'll be inspecting the edges of the VCG and do a beneath-the-car inspection as well. Getting tired of this issue.

I reached into the rear edge where the heat-shield ends and the PreCat O2 sensor wire emerges and there were residual oil from the heat shield to the wire.

Next, I attached red focused-spray-tube on BrakeCleaner bottle and sprayed a bunch on the heat-shield tray frontend.

I can see the BrakerCleaner flowing down towards the rear of the engine block, and down the PreCat O2 sensor wire.

Stuck my hand in there with a paper towel full of rubbing alcohol to clean that rear edge of the heat-shield and get rid of all the residual oil pool there.

Hopefully, this works.

DrivingPassion · 12-02-2021, 01:21 PM

Got an endoscope from AMZN.
This weekend, I will be doing a good thorough inspection of the VCG edges to rule out oil leaks from the new 2-week old VCG.

kazbek1 · 12-02-2021, 03:42 PM

Quote:

Originally Posted by DrivingPassion

Got an endoscope from AMZN.
This weekend, I will be doing a good thorough inspection of the VCG edges to rule out oil leaks from the new 2-week old VCG.

That's the one I have too. Pretty good quality for the price!

Cloverdale · 12-02-2021, 04:34 PM

And hand cleaning of heat shield removed with degreaser using a tooth brush can result in some significant episodes of smoke until it burns off. Don't panic!

DrivingPassion · 12-02-2021, 04:38 PM

Quote:

Originally Posted by Cloverdale

And hand cleaning of heat shield removed with degreaser using a tooth brush can result in some significant episodes of smoke until it burns off. Don't panic!

I used BrakeCleaner and rubbing alcohol. They were already gone before I test-drove the vehicle.

I'm going to keep an eye on this for the next few weeks.

07-09-2021, 05:39 AM	#1
cstavaru Brigadier General 313 Rep 3,262 Posts Drives: 2009 335i M Sport Sedan 6MT Join Date: Aug 2008 Location: Bucharest, Romania iTrader: (0)	Here is why your valve cover still "leaks" after replacing the N54 valve cover gasket This problem drove me nuts after first replacing the valve cover gasket and then the next day the valve cover entirely, only to have oil profusely "leaking" on the turbochargers and raising worrying amounts of smoke from the engine bay. It drove me nuts so much so that I made it my sacred mission to solve the mystery. The forums are full of people having "leaks" after replacing the valve cover, re-doing it, replacing the cover, re-replacing everything, etc. After all these years no one solved the mystery in a scientific way, everybody said things like "cover is cracked, cover has invisible cracks, gasket is pinched, turbos are bad, oil filter housing gasket is bad, check the rear main seal", etc. Nonsense ! Of course, those problems can arise, but they have to be scientifically diagnosed by looking at those areas with an endoscope or other means (by the way, I highly recommend investing $30 or so in an endoscope !) Over time some people did suggest that the heat shield is the culprit, but they thought that cleaning it with brake cleaner and pressure-washing it is enough. This created an even worse problem: people have a clean and shiny heat shield that pools oil so they think: "now that the shield is clean and there is still oil pooling and smoke, I surely messed up the valve cover replacement or the cover is cracked or whatever". Nothing farther from the truth ! Look at the heat shield in the video: it is fully cleaned with brake cleaner and then pressure washed. As you can see, those methods have no effect whatsoever. My advice: when replacing the valve cover gasket, it is mandatory to remove the turbo heat shield (it is nothing compared to the other parts of the valve cover job) and heat it on a gas stove and remove all oil that comes up. Using a blow torch would probably work too but it can cause cosmetical damage if held too close to the shield. You're welcome ! __________________ Mods(click): Cobb + RB Turbos \| Aquamist HFS-4 Meth \| Drexler LSD \| Bilstein B12 Pro-Kit \| Custom K&N Apollo Intake \| Wagner Intercooler \| Macht Schnell Downpipes \| BMW Performance Power Kit \| BMW Performance Exhaust \| BMW Performance Short Shifter \| M3 Subframe Bushings \| Last edited by cstavaru; 07-09-2021 at 01:10 PM..
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07-09-2021, 07:09 AM	#2
NoGuru Major 772 Rep 1,418 Posts Drives: 335is Join Date: Apr 2017 Location: MI iTrader: (0) Garage List 2021 Chevy Silverad ... [0.00] 2002 Jeep Cherokee [0.00] 2014 CTS [0.00] 2011 335is [0.00]	Or you could just simply clean it with some brake cleaner. I see no science behind your method at all other then saying "this worked for me so it will work for everyone". __________________ 2011 335is DCT BQ Tuning / BMS CAI / VRSF kittyless DP's / Synapse BOV and charge pipe / 7" VRSF Race FMIC / Walbro 535 and 450 on BMP4 / E90 tune / Diff Brace / PR Coils / Relocation Inlets / DAW Stage3+ Turbos / MMP port injection / xHP Stage 3 / FPR and -6 fuel lines
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07-09-2021, 07:46 AM	#3
tcphoto Brigadier General 3524 Rep 3,042 Posts Drives: E92 335i 6MT Coupe Join Date: Dec 2009 Location: Nashville, TN iTrader: (1)	I guess that's one way of doing it... __________________
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07-09-2021, 10:35 AM	#5
mapleleaf1773 First Lieutenant 418 Rep 413 Posts Drives: 2011 BMW 328i XDrive Join Date: Jan 2021 Location: West Virginia iTrader: (0) Garage List 2011 BMW 328i XDrive [0.00]	It would burn off after just a couple trips if oil was stuck in the middle of those thin metal sheets - no big deal. Its more of a pain to get those pesky bolts back in after everything is put back together. Just my experience. OP, are your oil issues resolved? If not, id check the valvetronic motor gasket on the valve cover. Over time, the valve cover plastic weakens and that gasket (the seal of the valve cover against the gasket) becomes "more flimsy" hence oil leak that pools up and runs onto that metal bracket. That can be a pain in the @$$. Just my 2 cents
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07-09-2021, 11:23 AM	#7
mapleleaf1773 First Lieutenant 418 Rep 413 Posts Drives: 2011 BMW 328i XDrive Join Date: Jan 2021 Location: West Virginia iTrader: (0) Garage List 2011 BMW 328i XDrive [0.00]	oh ok, sorry didnt realize you had the n54
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07-09-2021, 01:47 PM	#10
mapleleaf1773 First Lieutenant 418 Rep 413 Posts Drives: 2011 BMW 328i XDrive Join Date: Jan 2021 Location: West Virginia iTrader: (0) Garage List 2011 BMW 328i XDrive [0.00]	yea true but im on a cell phone and im old. so i missed it
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11-19-2021, 11:05 AM	#13
kazbek1 Second Lieutenant 72 Rep 256 Posts Drives: 2007 335i Join Date: Mar 2013 Location: Vero Beach, FL iTrader: (0)	Hey guys, I'm having some difficulty getting the new bolts into the new valve cover. Is there a trick to sliding them in? I don't want to force them in with a mallet or use pliers to clamp them in...Any tips?
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12-02-2021, 10:14 AM	#14
DrivingPassion Lieutenant 130 Rep 485 Posts Drives: '15 M235xi Join Date: Nov 2006 Location: WA iTrader: (0)	cstavaru , What are the steps to remove heat shields ? I'm having the same issue: VCG was replaced recently (2 weeks ago) but I still get occasional oil dripped onto wire of the precat O2 sensor when I drive spiritedly and brake aggressively. I have a feeling that there is a small pool of oil on the heat-shield collected somewhere in the rear and when the car is driven aggressively, that oil is spilled out to the PreCat )2 sensor wire. I'll be inspecting the edges of the VCG and do a beneath-the-car inspection as well. Getting tired of this issue. __________________ 2015 M235i xDrive 8AT Last edited by DrivingPassion; 12-02-2021 at 01:20 PM..
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12-02-2021, 01:21 PM	#19
DrivingPassion Lieutenant 130 Rep 485 Posts Drives: '15 M235xi Join Date: Nov 2006 Location: WA iTrader: (0)	Got an endoscope from AMZN. This weekend, I will be doing a good thorough inspection of the VCG edges to rule out oil leaks from the new 2-week old VCG. __________________ 2015 M235i xDrive 8AT Last edited by DrivingPassion; 12-02-2021 at 02:15 PM..
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12-02-2021, 04:34 PM	#21
Cloverdale Second Lieutenant 119 Rep 255 Posts Drives: 2007 335i Jb4 & perf. mods. Join Date: Aug 2018 Location: Cloverdale, BC, Canada. iTrader: (0)	And hand cleaning of heat shield removed with degreaser using a tooth brush can result in some significant episodes of smoke until it burns off. Don't panic!
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