300 SD Possible Purchase

[Doug Vazquez]

I have never owned a Mercedes much less a diesel Mercedes, however I have owned several diesel trucks and my parents have owned Mercedes cars for many years.

My children are getting close to driving age (my son now has his learners permit) and I am looking for an older, safe, somewhat reliable car for them to drive (or me to drive when I would rather sit in a car).

I have seen two 1980 300SD for sale in my area. I drove one yesterday. It started very easily (it was almost 75 degrees), however after that the entire car started to vibrate. The engine smoothed out if you depressed the accelerator enough to raise the rpm to almost 1000. It still seemed to have a slight miss. Upon driving it, the transmission seems to need adjustment. The transmission did not shift from first to second until the engine was revving rather high, then it shifted hard. The next shifts wre a little better, but still hard. When trying to get the transmission to shift down I had to completely floor the pedal and there was quite a delay in the downshift. I looked at the transmission fluid dip stick before starting and the fluid was still pretty clear, though not new looking. It did not smell burned.

After returning the car to the lot, the engine still vibrated as it did when I first started it. I shut it down, waited a couple of minutes and it restared perfectly, with the same vibration.

Some of the plastic parts on the accelerator linkage ( they had vacuum hoses running to other areas of the engine) looked worn out and probably were not operating as designed. A hose running from the turbo ( I think) to somewhere else was broken and not doing anything.

The other car I have not driven yet, but I did hear it run. It did not vibrate as the previous one did. I plan to drive this one soon.

What might be some possible causes of this vibration and could it be just one bad injector? Does the transmission sound like it needs adjustment or is it more likely shot?

I would appreciate this input of this forum very much.

Doug Vazquez

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1994 Ford F-350 7.3 liter turbo diesel

[DieselGuy]

Doug,

I own a '84 300SD and I have experienced both problems in the past. Both the engine vibration(rocking) and hard shifts were just out-of-adjustment problems.

I'm not sure about the '80 models, but on my car behind the fuel injection pump there is a rack damper screw. It dampens the oscilation of the fuel rack within the fuel pump. A new damper screw cost me around $8 and it made a world of difference...it eliminated the rocking.

The transmission was also a somewhat easy fix. There's a vacuum control valve mounted on top rear of the injection pump that controls the shifting. if the valve is out of adjustment, it may be providing too little vacuum to the transmission therefore causing harsh shifts. There's a also a pressure cable (bowden cable) that controls shift points relative to pedal position. This could be out of adjustment causing it not to downshift until you floor it.

These are just simple descriptions of what may be the problems. They are very typical of these models. Once they are corrected, these are great cars to drive.

Nolan

[Doug Vazquez]

Thanks for the reply Nolan. I am going to drive the other car right now. It will be interesting to see if this one displays any of the conditions that the first one did.

The paint and body was in nice condition on the first one I drove. The interior was also nice except for the foam padding in the rear seat. The front seats were ok, but could use new padding also.

The one I am driving today is not as nice of condition but it did seem to run better.

I will let you know how this one drives when I get back.

Doug

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1994 Ford F-350 7.3 liter turbo diesel

[ctaylor738]

Sounds like a diesel in need of an idle adjustment and a well-trained tech to check out the transmission adjustments.

Be sure that the climate control works properly and especially that the AC blows cold air and the heater hot air. This area is expensive to fix.

Chuck

[Aaron]

Doug,

I use my '80 300SD as my daily driver every week going from Cleveland to Cincinnati (250 miles one-way). It's at 183,000 miles and running great! I love the W116 the best out of all the S-class cars because it has excellent handling and still retains the "classic" look. These cars suffered from climate control problems which are very expensive to put right. The servo valves were known to crack leading to engine coolant loss and the vacuum system which operates the air delivery flaps most always gives you somehting to tinker with! Central locking on these cars is pretty slow, and lines and diaphragms tend to leak. Most '80 models don't have sunroofs (mine doesn't either) why I don't know. The W116 in general was notorious for eating up driver's door window regulators (mine's eaten two) and had severe corrosion problems with bodies and chassis'. When looking at any 116, be sure to check the rocker boxes thoroughly for rot, especially around the jacking holes. Check subframe mounting points for rot and most importantly, make sure the front stablilzer bar which runs the entire length of the firewall is secured within its bushings to the firewall properly. To do this, take a long screwdriver and poke up into each wheelwell in the upper corner closest to the firewall. Poke all of the metal around the doughnut-shaped bushing and if any of the metal is soft, leave that car alone, it's getting to the "unsafe for the road" point. There was a factory recall on this problem but few of the 116s needed the reinforcement when they were new, now that they have aged and if they have been driven in heavily-salted areas, they're just doomed to rust.

Make sure all of the interior bits are complete and in good shape. MB no longer manufactures trim for them anymore so anything for the inside is going to be hard to come by. Pull up the carpets and make sure the floorpans have the factory indentations in them (sort of 1/2 rainbow looking). Slide under the car and check metal brake and fuel lines for corrosion. If they're rusted, it's a horrible (and expensive) job to replace them. Check each recessed area of the floor in the trunk for soft spots, as water would leak in there and rot out the floors.

Tires should be 185-14s but nobody puts original sizes on them anymore (originals had no aspect ratio) and I personally like the 195/70R-14s. Concerning the engine vibration, it definitely sounds like it is in need of some adjustments and a good going over by a competent MB mechanic in your area. My SD virates at idle but smoothes out when light throttle is applied, which is somewhat a normal characteristic of the 5 cylinder engine (as compared to the 4 cylinder in the 240D). The shifting points/smoothness on the tranny can be adjusted at the modulator valve. Other than these items to be wary of, the W116 300SD is a wonderful car, especially the '80 model as it loses the manual idle adjustment on the dash and in general is more "refined" than it's older bretheren. Good luck on the purchase!


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Rgds,
Aaron Greenberg
MB technician
Precision Motorcars, Cincinnati, Ohio
'67 250SE Cabriolet
'77 450SL
'80 300SD
'85 380SE
'86 420SEL
'89 420SEL
'93 300E 2.8
'74 Jensen Interceptor Mk.III
'81 DeLorean DMC12
'84 BMW 745i Turbo

[This message has been edited by Aaron (edited 08-06-2000).]

[Doug Vazquez]

I drove the second 300SD. It idled fine, especially after warm up. It did not have the body shaking vibration the first one did. The plastic cam follower on top of the engine that has vacuum lines running to and from it looked almost brand new (I think this has something to do with the transmission control). The engine was turning about 3000 rpm at 70 MPH. I was not sure if the transmission was in high gear(forgot to count the shifts) but all the shifts seemed at the proper time, and firm, but not overly harsh.The kickdown linkage could use an adjustment.

After returning, I opened the hood and the oil fill cap was leaking oil from it. It might have been turned past its sealing point,but seemed tight. Does oil leaking from the oil fill cap indicate anything negative?

The AC was working rather nicely. The driver side window motor was real slow as was the sunroof motor. The antenna motor was intermittent also.

The rear suspension was shot. Are these struts expensive and difficult to replace?

Thanks for the information.

Doug

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1994 Ford F-350 7.3 liter turbo diesel

Phenomenal posts. So far the majors have been covered pretty well.

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'89 420 SEL
'90 300 SEL
'84 300 SD (sold it)

[Larry Delor]

As far as the oilcap goes, if it still has the older metal one, it may just be "worn out" I get oil out of my cap after driving it fast, and I still have the old cap. If you have the rear hydraulics on that car, you might want to search the site for some info on that subject, it will probably turn out that you are in need of accumulators, wich will not cost an arm and a leg, just a finger or two.
The second one sounds more attractive...how many miles? How much $?
-Larry

[Aaron]

The W116 300SD didn't have rear hydraulics, only a few 450SELs and of course the 6.9 had that system. Rear shocks and springs aren't terribly difficult to replace, but the springs could be expensive. Otherwise, sounds like either one is a winner. The tranny on these cars shifts to second at a stop but drops to first when accelerating. This is to prevent creep at idle. If you do buy either one, I'm sure you'll be pleasantly surprised at its agility and wonderful ride! I'm getting closer and closer to toying with the idea of finding a nice southern rustfree body to transplant my driveline into when my body crumbles to bits! I love this car!

P.S.--Don't worry about the oil cap. Get a new one.

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Rgds,
Aaron Greenberg
MB technician
Precision Motorcars, Cincinnati, Ohio
'67 250SE Cabriolet
'77 450SL
'80 300SD
'85 380SE
'86 420SEL
'89 420SEL
'93 300E 2.8
'74 Jensen Interceptor Mk.III
'81 DeLorean DMC12
'84 BMW 745i Turbo

[This message has been edited by Aaron (edited 08-07-2000).]

[Larry Delor]

Ooops! I was thinking of the W126 SD's. Duhhh, sorry 'bout that!
-Larry

[Doug Vazquez]

Thanks all for the replies. I will ask some more questions and answer some.

Aaron: The rear springs seem OK because the rear looks like it sits where it is desinged to sit. Are the shocks seperate from the springs? In other words, it is not a Macphearson strut sort of set up?

Nolan (Diesel Guy): Did your engine rock, cold or warm? I am not sure that the engine rocked, but it did shake enough to make the upholstery visibly shake and the steering wheel vibrate. This happened cold and warm. It seemed to be fine at road speed.

About the vacuum control: Is the vacuum control the plastic cam looking part that has what looks like two valves that open and close as the cam rotates during different throttle settings?

Larry: Both cars have about 190,000 miles. They are asking $3,300 for the gold one with the vibration and transmission problem. Also the climate control does not seem to work and the tires are shot. It handles better and is the better looking of the two (the foam is totally shot in the rear seat but the covers are in good shape and the carpet pieces are all there). The cruise control almost works in this one.

They are asking $3900 for the blue one. It has pretty good tires. The cruise does not operate, but the climate control works (at least the AC does) The body is in pretty good shape (there is a slight kink in the hood on the drivers side, it looks like somebody closed something in the hood). The paint looks like it would buff out pretty nice. The interior upholstery is in pretty good shape, except for a small tear on the drivers door window sill, a missing carpet trim piece, and pretty flat foam on the seats.

The drivers side window motor,the sunroof motor and the antenna motor have all seen better days. the dealer says if he can get close to the asking, he would fix these. I would also want the shocks replaced and the cruise operating also.

I appreciate all your input very much. This is a very informative site and I will pass along the address to my parents.

Doug

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1994 Ford F-350 7.3 liter turbo diesel

[DieselGuy]

Doug,

My engine did literally rock from side to side shaking the whole car. If you saw vibrations other than that, it may be an indication of other problems..idle set too low, or rack damper screw too tight (if w116 diesel has one), dirty or worn injectors.


The vacuum control valve I am speaking of is white plastic and it sits on top of the injection pump. This may be out of adjustment or a vacuum leak somewhere (including the vacuum assembly that site on top of the valve cover). As the techs on this site have said before...adjusting the transmission should be done by someone who really knows these MB trannys.

Nolan

[Aaron]

Doug,

The shocks and springs are indeed separate items, unlike on a BMW which uses a MacPherson Strut. I hate those MacPhersons, they're a royal pain in the ass to change. On the MB, all you do is unbolt the shock at the top, undo it at the bottom at the control arm and viola! It slides out.

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Rgds,
Aaron Greenberg
MB technician
Precision Motorcars, Cincinnati, Ohio
'67 250SE Cabriolet
'77 450SL
'80 300SD
'85 380SE
'86 420SEL
'89 420SEL
'93 300E 2.8
'74 Jensen Interceptor Mk.III
'81 DeLorean DMC12
'84 BMW 745i Turbo

[Doug Vazquez]

Thanks again for the replies.

What do you think about what the dealers are asking for these cars? Is this about right, or are they asking too much for the condition they are in?

I think I will go poke around the blue one again with a print out of your posts with me. It is on the way home from work so is easy for me to do.

Doug

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1994 Ford F-350 7.3 liter turbo diesel

[jbrasile]

quote:

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Originally posted by Doug Vazquez:
Thanks again for the replies.

What do you think about what the dealers are asking for these cars? Is this about right, or are they asking too much for the condition they are in?

I think I will go poke around the blue one again with a print out of your posts with me. It is on the way home from work so is easy for me to do.

Doug

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Doug, $3900 seem too much for what you described. I would look some more. There are some really nice ones out there that might even cost a little more but will give much more satisfaction. I owned a 1979 300sd until 1998 and sold it with 287000 for $3500 and mine was immaculate. I bought mine in 1991 for $9000 from a MBZ dealer when avg prices were $5000. Never regreted it, car perfomed flawlessly. Try to find something nice from an MBZ dealer (very hard due to age) or from a private party. If you have any more questions about the 300sd or any 116 cars let me know. Good luck.
Regards
Joe Brasileiro
1980 450sel