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Here is why your valve cover still "leaks" after replacing the N54 valve cover gasket
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07-09-2021, 05:39 AM | #1 |
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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 !
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Last edited by cstavaru; 07-09-2021 at 01:10 PM.. |
07-09-2021, 07:09 AM | #2 |
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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".
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07-09-2021, 08:16 AM | #4 |
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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.
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07-09-2021, 10:35 AM | #5 |
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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, 11:14 AM | #6 | |
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PS: The N54 engine does not have Valvetronic |
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07-09-2021, 11:23 AM | #7 |
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oh ok, sorry didnt realize you had the n54
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07-09-2021, 11:35 AM | #8 | |
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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, 01:47 PM | #10 |
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yea true but im on a cell phone and im old. so i missed it
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07-09-2021, 02:25 PM | #11 |
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I understand
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11-19-2021, 11:05 AM | #13 |
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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 |
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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.
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Last edited by DrivingPassion; 12-02-2021 at 01:20 PM.. |
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12-02-2021, 10:16 AM | #15 |
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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.
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12-02-2021, 12:53 PM | #16 |
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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.
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12-02-2021, 12:55 PM | #17 |
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Got it. Thanks for the clarification.
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12-02-2021, 12:59 PM | #18 | |
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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.
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12-02-2021, 01:21 PM | #19 |
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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.
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Last edited by DrivingPassion; 12-02-2021 at 02:15 PM.. |
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12-02-2021, 03:42 PM | #20 | |
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12-02-2021, 04:34 PM | #21 |
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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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12-02-2021, 04:38 PM | #22 | |
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I'm going to keep an eye on this for the next few weeks.
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