fred email@example.com wrote in message
By far the biggest headache is the automatic climate control system.
Failures of either the amplifier or the servo are common. Either can
be easily replaced, the AMP goes for about $120, the servo $600. The
servo most commonly fails by developing a coolant leak, which isn't a
good thing in a unit with 4 cooling hoses, about 10 vacuum lines, and
about another 10 electrical connections all hooked to it. If you do
need to replace the servo, Performance Analysisn in Tenn. sells
remanufactured ones that replace the lower crack prone plastic housing
with an aluminum one. And if it fails, they will fix it for $100 for
Check cars you are looking at by cycling the climate control from full
heat to full cooling and make sure everything is working. IT is also a
good idea to do this periodically about once a month, as this runs the
motor, mechanism, feedback potentiometer, etc in the servo through
it's full range.
The servo is under the hood, near the firewall, passenger side. Make
sure there is no sign of coolant leaking.
Other things to look for are rust, which could be a big problem
depending on where the car was driven. Pull the floor mats, front and
rear and inspect for rust there. I just pulled some parts from one
headed to the junk heap, and in front there was no floor left, you
could see the road. I suspect this one rusted from the inside out, as
that area is common for water pooling from blocked AC drains, window
leaks, etc. And check the vacuum system which works the door locks,
trunk lock, fuel lock, etc. to make sure it works. The system is
complex and can develop leaks.
If you get one in good condition, these are tough strong cars, some
would say among the best MB has made. I had an accident recently,
where I hit a 3 year old chevrolet. I barely felt the collision, the
Chevy was totalled, I drove the 300SD home.
I've owned one of these since it was new. The engine is solid, also the
transmission. The engine is simple and easily maintained by a DIY owner.
The 1980 model has an aluminum hood, trunk lid and firewall to reduce
weight and the engine's cam was modified to make 120 HP vs. 110 HP in
prior years. I averaged 24 mpg in commute driving and about 26 mpg on trips.
This car's flaw is its complicated climate control system which is fine
when all is in order. The problem for a buyer of such a 24 year old car
is that someone has tried to fix it and has messed it up. The CC system
has an "amplifier" (logic board) and a "servo," that monster in the
right rear engine bay. Both these parts break and both can be bought as
rebuilt parts so don't even think of calling the dealer about them. In
my experience most problems are from one or the other of these parts.
I've had two other problems: the aluminum window guide on the
passenger's front door bent and the regulator failed. The engine air
cleaner's support bracket breaks from metal fatigue - I had the last new
one reinforced by a welder before I installed it.
The 116 has a reputation for rust but my car has none as it's never
driven in snow or salted roads.
The 116 turbodiesel is a fine car, I hope you can find one in good
I aquired a 1980 300SD about three months ago and from several
web sites, I find that they ALL have the same common problems.
1. The "servo" in the Climate Control system had failed three
previous times in my car. About $500 for a rebuilt unit.
Living in Florida, I have bypassed the automatic features of
the servo and now have just two levels of airconditioning.
From the junkyard, I have aquired three more servos for about
$15 each and am in the process of making two useable units
from the four that I have. MB purchased this CC system from
Chrysler where it was used in the early "70s Imperial.
2. The Cruise Control suffered the same failure mode as every
other 116, solder joints. I replaced the amplifier with one
from the junkyard, it works sometimes.
3. Engine and transmission mounts were in real bad shape, replaced
them myself for about $65.
4. The air cleaner mounting bracket breaks on them all. I picked
up one at the junkyard and even it had broken (same place) and
had been welded. I had mine welded, so I now have a spare.
One of the three rubber shock mounts had to be replaced, $3.
5. And of course, the horsehair padding in the door panels had long
ago turned to powder. Replacement with new foam rubber was only
about $25, but labor intensive. Be careful removing the interrior
door panels, they lift up and off, not like others that are pryed
The following web site has the maintenence and service manual on-line.
Good luck! I got a good one!
Tarpon Springs, FL
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