Valve stem seals...becoming a normal thing

Nov 8, 2016
17
16
0
McHenry, IL
We are on our tenth n54 that is in need of valve stem seal replacment this year. It seems like it's becoming the norm for higher mileage n54s. 70k miles and up. We have been getting quite a few smoking n54s, not all have just been valve stem seals, but upon removal of the turbos we have seen about 80% of the cars needing them that come through our shop.

20161108_065629.png

Heres is what a leaking valve stem seal would like look wit has the turbos removed
20161108_065724.png

Special tool needed to release tension of the valve springs so the cam can be removed, without this you run a risk of cracking or damage.
20161108_065704.png

Shop air is forced into the cylinders to keep the valves in place sof once the keepers are removed it does not fall into the cylinder.
20161108_065646.png

Our special tool needed to be able to replace them in the vehicle, the conventional way is removing the whole head and doing it on a bench or such.
 
Last edited:

sirdaft1

Specialist
Nov 11, 2016
75
57
0
Chicago
@Michael@GermanAutoWerks did my valve stem seals @ 152kish miles. It sounds like the rubber seal material just hardens up over time and loses its ability to seal properly. It's not a simple or cheap job, but it should absolutely be budgeted in if you have higher mileage and they've never been replaced.
 

doublespaces

Administrator
Oct 18, 2016
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ultimately, its the compound of rubber BMW used on these specific seals that cause the issue.

Good to know. Its probably not even worth investigating a solution, considering the fact that by the time you notice the issue a second time, you'll have put quite a few miles on the car...
 

Xshadows

Corporal
Nov 4, 2016
122
72
0
Sanford NC
This really makes me just want to pull my head, do cam bearing ledges, valves guides and seals, clean everything and do a mild port and polish job. Considering I'm at 120k miles and all..
 

sirdaft1

Specialist
Nov 11, 2016
75
57
0
Chicago
This really makes me just want to pull my head, do cam bearing ledges, valves guides and seals, clean everything and do a mild port and polish job. Considering I'm at 120k miles and all..

@Michael@GermanAutoWerks can chime in, but you may not need to swap the guides - which would make the entire process much more in depth (ie: remove the entire head). Sometimes the rubber valve stem seals just harden over time and it's not due to worn guides.
 
Nov 8, 2016
17
16
0
McHenry, IL
This really makes me just want to pull my head, do cam bearing ledges, valves guides and seals, clean everything and do a mild port and polish job. Considering I'm at 120k miles and all..

I mean if you have the extra money then why not. But for most of the n54 owners doing just the seals will more then sufficient. I guess it depends on your goals for the car. I mean at that point why not just pull the motor and build it? We're does it end ya know? If it were my personal car I'd do seals and inspect the cam ledges for wear and be done with it. Head porting hasn't shown enough gains vs cost in my book.
 
Oct 24, 2016
1,152
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Scottsdale, AZ
Local shops around here still say that needing to do valve stem seals is pretty rare... but I imagine that number can't go anywhere else but up. Good to get info on what it looks like out there. There are a few chemical solutions out there that can prolong the need to do the real work... do you have an average mileage you start getting suspicious at?
 

AD-ENG

Corporal
Oct 22, 2016
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39
This is often a temporary fix. The worn guide is the bigger issue. Seal is working overtime on a stem dancing around in a worn guide.

No intention to thread jack, but our guides will be available soon.

This is a good topic as most guys immediately blame the pcv system and turbos at the first sight of smoke. With more n54s making higher power and becoming higher mileage the guides and seals are more likely the issue.
 
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Nov 8, 2016
17
16
0
McHenry, IL
This is often a temporary fix. The worn guide is the bigger issue. Seal is working overtime on a stem dancing around in a worn guide.

No intention to thread jack, but our guides will be available soon.

This is a good topic as most guys immediately blame the pcv system and turbos at the first sight of smoke. With more n54s making higher power and becoming higher mileage the guides and seals are more likely the issue.

We have measured 3 heads now that had them leaking and all were within spec. How many have you had that were out of spec?
 

AD-ENG

Corporal
Oct 22, 2016
122
140
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39
What bmw considers "spec" (.031" of play iirc) is looser than seal with some miles can handle (on an oem valve).

Everything head we've had apart has needed exhaust guides or at least too close to chance.
 

TurboMike

Corporal
Nov 22, 2016
113
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PA
Could you explain exactly what I should be looking for. I have my turbos off now but not sure what I should be looking for. I saw the picture you have posted But I'm unsure if I should be looking for oil or what.
 
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Reactions: Dennis
Nov 8, 2016
17
16
0
McHenry, IL
Good info! Just another problem to add to the n54 motor. Unfortunately not something id ever own personally, turbo s54 is the way to go in my book.

You are looking into the exhaust port on the head and making sure there is no wetness around were the valve goes into the head or anywere in there. It won't be pooled oil, most likely just look dark and not sooty like a non leaking valve would. Compare each cylinders to make sure they all look the same.
 

STE92

Corporal
Mar 3, 2017
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What chemicals are you talking about?


Local shops around here still say that needing to do valve stem seals is pretty rare... but I imagine that number can't go anywhere else but up. Good to get info on what it looks like out there. There are a few chemical solutions out there that can prolong the need to do the real work... do you have an average mileage you start getting suspicious at?
 
Oct 24, 2016
1,152
1,202
0
45
Scottsdale, AZ
What chemicals are you talking about?

a bandaid that will swell the rubber- it's about a good idea as using Blue Devil headgasket fixer lol.
Don't give in to snake oil.

Pretty much. In a pinch they can get you by for a bit but when it's time to do mechanical work there are no real substitutions.
 
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