560 sl questions

I recently purchased a 1986 560 sl and am now trying to get some of the mechanicals done. The car has 123,000 miles on it and is using oil. When I first start it I see a liitle blue smoke. but not when I punch it hard. The mechanic tells me the compression in each cylinder is 150psi and holding. He feels its probably valve seals but is not sure. Any ideas? Also the car seems to be heavy on gas..Is this because it's a V-8? Lastly the car seems to ride hard like an old Vette , the shocks are ok is this the nature of the car?
Thanks for any help
Larry

[Tom McMenamin]

Hi Larry!

I purchased a 1988 560SL this past Summer and have found it to meet all of my expectations.

I experienced many of the same things you mention in your Post.

The previous owner of my car was an older gentleman who traded the car due to oil consumption (1 qt per 400 miles) The dealer told him that he needed New Head Gaskets, Valve job, and seals and guides. By the way he was told to do the Timing chain while everything was open.

After searching this Board panic stricken over the size of this bill I did several things.

I searched for and found, after 3 tries, a reliable mechanic. This is the most crucial. How do you do that? Well, what I did was have simple things done and then get feedback as to what they thought the car needed and then checked the archives to see if indeed these things that they mentioned tend to go wrong. For Example, I had the trans oil and filter changed and the differential and the cooling system changed at one place. They overcharged me for the Cooling system and wanted me to have the flaps in the heater overhauled. (Ineeded a Monovalve) Nixed him!
Next guy said that he wouldn't do the valve seals unless he did the Headgasket! Nixed him! Third guy went over the car, told me where to buy a monovalve and that he had never seen a 560 that the headgasket didn't have some leakage. He said the he doubted the valve guides were bad and that a simple valve seal job would solve my problem! He also mentioned it could be done without taking the head down Toal Cost 700 bucks. Oil consumption is now 0.

Your issue is going to get resolved but notoriouly the headgasket tends to be a problem! If someone didn't mind the store on the car and you need one you are looking at big bucks! That why you need someone you can trust! Valve Seals are always a problem on the 560 and they all need them. The question is can you get away with just seals?

Unless you see alot of seepage from the headgasket at the rear of the engine you probably are OK. By the way the valve cover gaskets weep as well so its hard for the amateur to tell whether its Headgasket or Valve cover gaskets! At any rate they replace the vcg when they do the seals.

Maybe go for the seals and get a sound opinion on the Headgasket! either way your oil consumption should go away!

The ride is OK for me as I am used to BMW and the ride is about the same maybe a little better! Remember its a straight axle and thats not designed for a Cadillac ride!

Do yourself a favor and get all the fluids done. People who bought these cars had a little dough and they are notoriously sloppy about maintenance.

Its the nicest car i have ever owned! I Love everything about it and wish I could have found one 3 years ago! If you straighten it out from previous owners and keep the maintenance up you'll Love yours as well!

Hope this helps!

[maheath]

Like Tom, I too purchased a 1988 560SL this summer. It was consuming about a quart of oil for every 100 miles. My regular mechanic was afraid that I was going to need a head job and told me to take it to a Mercedes specialist. He even recommended a good one.

They took a look at it and replaced the valve cover seals ($140). That didn't seem to make much of a dent in the oil consumption. Then they replaced the valve stem seals ($720). Now I have 0 oil consumption. Mine still had the original stem seals and they were shriveled and hardened after 14 years of use.

Unfortunately, mine is in the shop today getting a new alternator and ABS sensors.

[maheath]

I should have added that the mechanic should pull the spark plugs to check for oil. Mine was leaking in 7 of the 8 cylinders.

[Tom McMenamin]

I forgot about that! Always change the plugs after seals! Regardless!

They are generally fouled at least one or two or maybe more!

Cheap investment for continued Happy Motoring!

Oh! I forgot!

The gas mileage question that Larry asked! The 560 can pass everything except a gas station. They love, dearly love premium gas!

I don't know what mileage I get per gallon but its not good! Maybe 12-15 ?

Yesterday was the day I finally brought the Mercedes to an expert. Who said I definetly need valve seals to reduce the oil use.I should also replace the timing chain not knowing if at all it had ever been replaced. Well, the total for this fix should be $1300. I guess things in N.Y. are more expensive. I am hoping this takes care of the problem. Anyone know where I can get a new door panel in dark blue for this car??
Thanks
Larry

[maheath]

If your not sure about the timing chain, go ahead and have it, the guides and tensioner replaced while they have the valves open. You'll save on labor that way.

When they replaced my valve cover gaskets, they inspected the chain and guides. They found that my chain was new, but the guides weren't, and one of them was broken. I had the tensioner and all the rails replaced while they were in there and it cost an extra $420 on top of the valve gasket work.

At least I don't have that to worry about anymore.

[maheath]

On the mileage, I get about 15-16 MPG in mostly city driving. It doesn't do much better on the highway.

The owner's manual recommends a minimum of 91 octane. Around here that means I put in 93 octane. I also put in fuel injector cleaner about every fourth tank.