Hello, I have a few questions for you w123 diesel 4 door experts. As for I
have absolutely no experience with any Mercedes of any kind So bear with
I just recently purchased a 1983 300D turbo with 183,000 miles without
test driving it before paying a few hundred dollars for it. It does not
start right away unless it is being jumped. When it does run and in
idle, I think it sounds OK. But I am not sure what I should be hearing to
warrant that assessment. What can I do to check if the engine is in good
When it drives, I think it rides smoothly but has a few questionable
1. It has very slow pickup. I feel like it is going to take me 10 minutes
to get to 60 miles per hour. Is this normal for this type of vehicle?
2. When turning into corners kind of fast, the front end makes a clunking
noise. Do I need to replace the struts or something like that?
3. The steering wheel seems like it has way too much play, what can I do
to tighting it up.
4. The A/C unit does not blow cold air. Do you know if it will cost an
arm and leg to have it fixed? Someone told me that is vehicle had a
history of A/C problems. Is that true?
5. Battery Issue, Are there things or accessories that shouldnt be left
on that I should be looking for that may drain the battery?
The car body and interior is in decent shape, But I do want to spruce it
up a bit.
1. What is the best way to restore or find replacement wood for the Dash.
2. Where is a good place to buy a reasonable priced new Dash cover.
3. Also the Rear Deck fabric needs replacement, where can I get one.
4. I need a door guard molding on the left rear door.
5. I need replacement moldings for both front and rear bumpers. The
current ones are being held up by duct tape.
Lastly, Is there anything else I need.
Thank you in advanced! Any help will be greatly appreciated!
Re 1. A regular diesel from the era took about a week to get to 60 mph :-)
(I had a 1980 W123 200D from new, 60 PS). A turbo, especially a 3-l one,
should have a bit more oomph but won't be like a modern diesel engine. I am
sure somebody with 300 turbodiesel experience -- quite a few here -- will
chime in shortly.
Have you driven diesels before?
For direct contact replace nospam with schmetterling
"hamwitty" < email@example.com> wrote in message
A turbo 617 runs very well when it is running correctly. Yours is not.
A few things to check:
1) Air cleaner.... is it plugged? I have seen them covered in oil from too much
blowby. I have seen
them completely packed full with dog/cat food
2) With the engine off! Remove the black plastic U tube in front of the air
cleaner. Reach in the
front of the turbo, you can use a finger, and see if the turbo spins freely. It
3) Look at the back end of the intake manifold. You will see a banjo bolt and a
white nylon tube.
Follow it from the banjo bolt across the firewall ti the switchover valve by the
brake booster. Is
it broken any where?
4) Now follow the other hose that comes out of the switchover valve to the
enrichment diaphragm on
the top of the injection pump. Is it broken any where? Or even connected? If
5) Get a 12mm wrench and remove the banjo bolt on the end on the intake.
Careful, don't loose the 2
seal washers. With the bolt out, you will see that it is a hollow screw. Boost
the intake, boost pressure goes thru the banjo bolt, thru the tube, thru the
switchover and pushes down on the top of the the enrichment diaphragm. Is the
bolt plugged with
If yes, clean it out.
If no, remove the end of the tube from the enrichment unit. Try to blow thru the
tube from the
enrichment unit end. Can you? It should be wide open all the way to the intake.
If no, remove the long tube end from the switchover valve. Blow thru the
enrichment unit end. Can
you? [see b below]
If no, the switchover valve is plugged with crap.
If yes, blow thru the tube from the end of the switchover valve to the banjo
fitting. If no, it is
plugged. Get a new hose from your dealer.
b from above: If yes, you can blow thru the tubing from the enrichment end to
the banjo fitting with
no problems. Turn the key on. Look on top of the intake for the single wire
pressure switch. While
holding the switchover valve with one hand, unplug it and plug it back in. Does
the switchover valve
click in your hand? If yes, the pressure switch is bad.
With all the tubing wide open and clear, drive the car. You should feel fuel
enrichment come in at
about 15 mph with the turbo boost.
<snip>2. When turning into corners kind of fast, the front end makes a clunking
BE VERY CAREFUL!
This could indicate a loose or broken steering component (tie rod, drag
link, damper) or severely worn ball joints.
These are serious, potentially life threatening issues! If they break
while you are at speed, the car will be out of control.
Make sure to safety inspect the front end, or have someone
knowledgeable do it before driving...
If this is a real inquiry and not a spoof you ought to take this wreck
to an independent M-B shop and have them fix its problems. Do that
before thinking about its cosmetic issues - if there any $$ left for that.
First off Thanks Karl and Martin for your info that's very helpful.
As for calling it a wreck, It actually has a great solid body and fine
interior... Not junk! I thought of taking it to an Independent MB shop to
have it looked over but decided to ask all o your opinion on things first.
Also I would like to work on the mechanical myself to gain experience with
Mercedes and diesels. Hence why I purchased it.
Like I said, Any helpfull sugestions would be very apprecitated!
Thanks again in advance.
OK, fair enough, you're serious about some DIY. Welcome.
A compression test will tell the internal condition of a diesel. Since
you already own the car remember this for the next one.
Hard start: On the left fender is a black box with wires going over to
the engine's glow plugs. Slide the plastic cover UP - under it is a
"fusable link" or 80 amp fuse. If it's broken you need to replace it for
the glow plugs are NOT working and the engine won't start in cold
weather without them. The link costs about $2 at a dealer.
Acceleration: Karl told you how to clean and check the ALDA circuit. Do
that. Then note how the transmission shifts. If it shifts up too soon
the engine can't reach its (120 HP) power range and needs an adjustment.
That may be the problem.
This car has a 0 - 60 time of about 13 seconds - when its in good shape.
That's the goal.
This old car has been neglected so you need to correct that deferred
maintenance. A diesel is a simple engine that needs lots of air, some
fuel and good compression to run well. The engine's air filter ought to
be clean as should its two fuel filters - the small clear plastic one
and a spin on can up near the valve cover. If the engine stinks of fuel
the "bleed off lines" between the injectors ought to be replaced - buy
4' of "bleed off hose" and cut the old hoses off using a utility knife,
one at a time, and replace them. The short stub on #5 cylinder has a
steel plug - push the plug into the replacement stub hose BEFORE pushing
the hose onto the injector's barb.
This engine has mechanical valves - that means they need to be adjusted
every 15K miles or the engine will lack power and have hard starting -
for lack of compression. This adjustment can be a DIY job for an owner
who's patient and careful. I can send you directions if you're interested.
Noise in front end. Could be dangerous - ball joints, tie rods, or not -
stabilizer bar bushing. It needs to be checked and fixed. It could be
due to bad idler arm bushings - as could the poor steering response.
Look down the right side of the engine to the idler arm while someone
turns the steering wheel from side to side while you observe the idler
arm. If it lifts rather than pushes the right wheel its bushings are
worn - a $30 idler arm bushing kit will fix that. Play could also be due
to a bad steering coupling - look at the coupling just above the
steering box. Turn the wheel - is there play in the coupling. If so,
replace it. On the steering box you'll see what appears to be an
adjustment. At this point DON'T. Fix everything else first.
Thanks T.G. for your understanding.
I am interested the Valve Adjustment directions. I plan to start working
on the car in the next couple of weeks, so gather info on how to do things
is my priority.
Thanks again for the good info.
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