Looking to buy an 1986 560 with over 140k on it. Just wondering what the
average life and miles on these are and general problems specific to that
car/engine. Looking for solid daily driver, and this looks to be a great
looking and solid car. Any idea what the gas milage is like on that V8.
Thanks for any and all input, opinions, and insights/recommendations.

"Chuck Grospitch" <chuckg4 (AT) cox (DOT) net> wrote

http://hometown.aol.com/dquinn5735/repairs.html

This model, 560SEL, was the "top of the line" back in '86 and designed
to be a corporate / government limousine. It was NOT designed for
economy or efficiency but for power and comfort. The fuel use is high
for the 5.6L V-8 was somewhat detuned to meet emissions standards, I
vaguely recall an EPA estimate of about 12 to 19 mpg. Others may have
better data.

The V-8 has a long dual chain that drives the overhead valves. The
chains stretch and wear and after 120K to 150K miles ought to be
replaced for when they break the valves will be smashed by the pistons
and the repair will cost about as much as you'll pay for the car. So if
the chains are original or you don't affirmatively know that they've
been replaced it's something to budget and do now or at least have a M-B
shop check.

The other item on the 560 model, but not the 420 model, is its
hydro-pneumatic rear suspension. There's a small engine driven hydraulic
pump, a leveling valve in the rear and two nitrogen and oil filled
shocks or struts - both in the rear. The hydraulic fluid is expensive
and the rear shocks or struts wear out. The symptom thereof is a
buckboard hard ride. YOU need to understand how this system works to
avoid being at the mercy of some repair shop that wants to "replace
everything", for "everything" doesn't need to be replaced, usually only
the struts go bad.

Since you like the S model you should know that it was also sold as a
420SEL with a 4.2L V-8, slightly better fuel economy and regular steel
spring rear suspension, otherwise very similar. Also available is the
300SDL which is the 420SEL except that a 3.0L straight six diesel
provides the power. These diesel models are well regarded, unfortunately
they're so well regarded that finding one with less than a zillion miles
on its clock is difficult. Its diesel is quite durable but suffers
cylinder head cracks or a blown headgasket if overheated, just in case
you buy one.

In regard to the timing chain, the general rule of replacement is l00K miles
and/or 10 years. Actually the chains rarely break on their own. Usually
the chain failure is caused by the plastic chain rail guides getting
brittle with age and breaking, then dropping into the chain links causing
the chain to jump time and trash the piston/valve components. I own an '86
560 SEL and depending on the quality of the fuel, the car gets around 15/16
in city driving and 18/19 on the highway. California gasoline is blended
differently than most of the fuel in other states because of air quality
issues. My MB does not run or idle as good with the CA stuff.....it does
much better with out of state gas.
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"T.G. Lambach" <tlambach (AT) comcast (DOT) net> wrote