Valve stem seals...becoming a normal thing

[Michael@GermanAutoWerks]

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.

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

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.

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.

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.

 

[Michael@GermanAutoWerks]

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

I personally think it's that and related to the heat generated. Have you seen any guide problems? MMP stated he has seen all the heads he has touched needed guides which is not something we have seen at all.

 

[sirdaft1]

@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]

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]

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]

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.

 

[Michael@GermanAutoWerks]

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.

 

[Chris@VargasTurboTech]

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?

 

[Michael@GermanAutoWerks]

For anyone wanting to know how to check the valve guides for wear this is how per bmw spec:

 

[Jboyorak]

I'd imagine it would have to do with longer oil change intervals, and failure to take proper care of the pcv system...

 

[Nick380]

I am scared now, @ 119K and i'm doing turbos this week and next. I really hope I don't see leaking valve stem seals...

 

[AD-ENG]

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.

 

[Michael@GermanAutoWerks]

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]

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.

 

[Michael@GermanAutoWerks]

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.

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.

 

[TurboMike]

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.

 

[ATL-IS-N54]

Pending the shop rate yes something around that price.

Not too bad

 

[Michael@GermanAutoWerks]

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]

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?

 

[Alex@abrhouston]

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.

 

[Chris@VargasTurboTech]

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.