W126 500SEL Valve Guides / Stem Seal Replacement Queries

[Toot The Shoot]

Dear All,

If I am going to have the heads off my engine, for the purpose of replacing the valve guides, etc. could I ask for opinion on the following please?

1. Are there any other works I should have done at the same time?
2. How much should I expect to pay?
3. Can anyone recommend somewhere in the South East of England, preferably in the Sussex region, where I could get these works done?

I have an excellent, former MB specialist mechanic, that looks after the car for me, and he has priced the works (valve guides / stem seals only) at just under £1K.

I have no reason to doubt that this is a fair price, but it never hurts to get a second opinion does it?

Thanks in advance - Mike

 

[iscaboy]

Dear All,

If I am going to have the heads off my engine, for the purpose of replacing the valve guides, etc. could I ask for opinion on the following please?

1. Are there any other works I should have done at the same time?
2. How much should I expect to pay?
3. Can anyone recommend somewhere in the South East of England, preferably in the Sussex region, where I could get these works done?

I have an excellent, former MB specialist mechanic, that looks after the car for me, and he has priced the works (valve guides / stem seals only) at just under £1K.

I have no reason to doubt that this is a fair price, but it never hurts to get a second opinion does it?

Thanks in advance - Mike

I hope that is £1k for the entire job, parts and labour?

 

[grober]

Renew/check the timing chain/guides/tensioner depending on condition/ when it was done last.
Clean replace the oil feed pipes to the camshafts?? PeachPartsWiki: M116/117 Timing Chain Replacement

 

[jaymanek]

I have had them done on my 560 SEC and my Pagoda. Both times we have done them without removing the head. Although this does require some special (but basic) tools.
On the SEC, we have no idea how, but we ended up bending a valve so the head had to come off anyway.
On the Pagoda it was plain sailing.

It is a large job and if I were doing it for a customer, id want to take the heads off so that there is no risk of things going wrong.

I would definately replace the upper guides and tensioner whilst you are there. Of course if the head comes off, your mechanic will get a head gasket kit and change all the relevant gaskets.

Also change the rocker cover gaskets.

£1000 seems a tad high but there is a fair bit of labour involved.. For an average mechanic, id say there is 2 days work plus the cost of the parts..

 

[ianrandom]

I can recommend a place in Reading if you get stuck. They worked wonders with my 126.

 

[Ian B Walker]

If you are going to have the heads removed make sure that the valves are cleaned and lapped in again. Sorry if this is teaching a granny to suck eggs.

 

[rpe2]

I can recommend a place in Reading if you get stuck. They worked wonders with my 126.

Which one was that? JG or Star?

Ta

 

[khimani_mohiki]

i thought the threads in the block were only good for one torqueing and required helicoils to be inseted before re-assembly?

 

[jaymanek]

nope? these bolts arent even the newer stretch bolts, they are ok to use again as long as the engine hasnt over heated.

 

[Toot The Shoot]

Sound advice again.

Thank you all

 

[ray_hennig]

You're in Sussex, so ...

There's John Haynes in Worthing - used him years ago and all went well.

Also, there's Oliver Stoner at PCS in Horndean near Portsmouth. Pleasant, helpful chap who's got good reviews here.

Other chap I've dealt with a lot is Steve Redfearn in Wimbledon.

For something that big on that car, I'd be prepared to travel.

Bon courage.

RayH

 

[ianrandom]

Which one was that? JG or Star?

Ta

Star, very good quality and not very expensive. JG expensive and a wee bit snobby.

 

[Toot The Shoot]

Hmmm. Just got a price from John Haynes of Worthing.

£2500 + VAT

Think I'll be going with my mechanic's offer

 

[khimani_mohiki]

Diy?

 

[jaymanek]

I didnt day anything earlier but John Haynes isnt the cheapest.
He does however, know his onions better than any in the country, especially for older cars... I believe he is one of the few that can still service the air suspension on a grosser.

Its where Mr Clarkson had his £16K service done!

 

[Toot The Shoot]

Cream of the crop eh?

Well, it's a little out of my reach for the time being

No mad rush I suppose, just don't like the embarrassing plumes of smoke, or the smell.

Thanks for the info though.

Mike

 

[jaymanek]

absolutely..

You have to be careful how much you spend on these cars. I sell second hand engines for these at £300!

Only make the investment if you see yourself keeping the car long term.

 

[kth286]

why not just replace the valve stem seals initially (easily done without removing the head).

You might be pleasantly surprised how much this will reduce the oil consumption and smoke.

This is often all that is required as the rubber valve stem seals harden with age.

 

[jaymanek]

This does require special tools though - a lot of garages wouldnt have these...

 

[ray_hennig]

That's a good point ...

why not just replace the valve stem seals initially (easily done without removing the head).

You might be pleasantly surprised how much this will reduce the oil consumption and smoke.

This is often all that is required as the rubber valve stem seals harden with age.

When does it smoke? On the overrun (decelerating) or always? Overrun would suggest the seals may be the only problem and you might be returned to former glory for minimum outlay.

RayH