BMW 4.8 - Valve Seals

[Suresurf]

I have recently brought a 6 series. It’s 2006 with 95,000 Miles.

I have read up about common issues with these cars of this age and mileage. One of them is valve seals.

Fortunately my car has no signs of valve seal failure, but was wondering if there is anything I can do to preserve them.

Regular use of redex or similar additive? Regular long blasts up step hills. I am assuming the failure is carbon deposits or is it literally rubber seals perishing?

Any assistance appreciated.

[gf15]

Mine looked like they had perished @ 138k miles and 10 years old.

[eliot]

They go rock hard and simply no longer seal. Mine started to go at 113k and I replaced them at 117k.
You can rent the special tool to diy the job, but its not something a novice should tackle. There are specialists who can do it for around £1200.

I wrote up my diy change here:
http://mez.co.uk/page128.html

[Suresurf]

Thanks, I have also read some other threads on here. Some are saying the perish due to long life oil / time between oil changes. They are saying the V8 injectors leak small amounts of petrol in the oil. Leaving your car along time between oil changes means the higher level of petrol in the oil damages the seals.

[Sardonicus]

Suresurf said:

Thanks, I have also read some other threads on here. Some are saying the perish due to long life oil / time between oil changes. They are saying the V8 injectors leak small amounts of petrol in the oil. Leaving your car along time between oil changes means the higher level of petrol in the oil damages the seals.

Nah BMW just used a st supplier/inferior quality part for this essential item

[bmwmike]

Were those seals used on any other engines like the n43? It would he interesting to cross ref. Seems crazy to cut corners on such a cheap part.

[eliot]

bmwmike said:

Were those seals used on any other engines like the n43? It would he interesting to cross ref. Seems crazy to cut corners on such a cheap part.

Yes I think they were used on other engines as well.

[bmwmike]

eliot said:

Yes I think they were used on other engines as well.

Yeah I looked up the cross ref on realoem and as I suspected the stem seals are shared with the n4x engines which also are known for stem seal failure. Presumably being four pot and x2 bank of four pots there is some similarity enough to warrant their sharing across those engines.

[dmarkovina]

I understand that motor oils should include some additives for keeping rubber from drying out. To be on a safe side I turned to Liqui Moly and have been using their Oil Saver together with Ceratec on my 260k+ Miles E39 which was showing signs of age through higher oil consumption both via oil seeping past the valve seals as well as low friction piston rings. Very happy with the result - oil consumption down by two thirds and engine runs smoother than ever and even seems more powerful then when I bought it 11 years ago. Or I may be imagining it...(don't think so).

[iSore]

The problem is that these engines run very hot for emissions. Strip a 100'000 mile engine and the gaskets and seals are all rock hard. N Series engines just piss oil out for fun, horrid things.

[bmwmike]

iSore said:

The problem is that these engines run very hot for emissions. Strip a 100'000 mile engine and the gaskets and seals are all rock hard. BMW engines just piss oil out for fun, horrid things.

Fixed that for you

[dmarkovina]

bmwmike said:

Fixed that for you

Drilled a hole through the thermostat?