valve job
 

My 1986 560 engine seems to need valve guide seals. My mechanic tells me that he no longer will only replace valve guide seals as it has caused to many problems on jobs in the past. He wants to do a complete valve job for between $2500 to $3000.

Any comments or advice on this will be greatly appreciated.

Sounds like a lot of money to me...I would get a second opinion.

Hi Robert,

Please be more specific. :)

How many miles?

What are the symptoms you are experiencing? Excessive oil loss, smoking at start up? All the time?

From the info you have provided, I'd get a few more informed opinions.


Good luck!

I usually aproach the job with seals up to about 150k. We always remove all plugs and do the cylinders first that show the most oil carbon on the plugs. We do the seals untill we find a guide that is beyond tolerance. That tolerance is based on experience as it can't truely be measured with the valves in the guides.

We look for tightness, condition of the seal retaining groove and the movement of the valve in the guide. The later seals will accomodate lots of play; burning a valve never happens. The whole job pays 5.5 hours. With seals and gaskets over $400.

Valve Guides
 

Six months ago I had the valve stem seals replaced and timing chain replaced on my'86 560SL due to excess oil usage. For a cost of $1400. It seemed to have solved the problem for a few months. The oil useage came back. Yesterday I picked up the car after spending $2500 for a full valve job . It seemed the valve guides were worn on a few cylinders. The car has 124,000 miles on it. It runs great more power than ever before. My advice do a valve job rather then the seals for now. Eventually it will need the valve job. Save your money and go for the full job(my humble opinion).

Larry '86 560 SL

If the alternative is $1400 for seals by someone who is blind or $2500 for the whole deal there is no choice. Since the proper alternative should be seals for $450 versus $2800 for the complet job when necessary. Whats the decision.

Obviously if your tech can't tell when to do which, then its Russian roulette.

We are doing a chain failure on a grey market 420SE this week who knows how many miles. Four exhaust valves bent like pretzels. Virtually no wear in the guides we are replacing. I would never do a valve job without the guides, but untill there is a real reason, I let my customers keep their money. Anyone wishing to do the whole thing anyway, no problem.