Mercedes 300D Suggestions

bordenk

I have an odd question and will appreciate some assistance. I am building a street rod, and would like to use the engine and drivetrain from a 1987 Mercedes SDL with another chassis. There is a good engine/drivetrain available to me in a body that is beyond repair, but I need the specs on the axel and rear differential in order to know whether it will work with the chassis and body I am going to use.

Does anyone know what the differential ratio is and what the width of the rear axel is wheel-to-wheel OD?

Thanks,

Karl Borden
bordenk@charter.net
717-202-0408

goldcar

I have a 1982 300D and plan to drive from SF to Tahoe in a week or so with it. My main concern is the heat on the way up. What can I do to make sure I am getting maximum cooling for the engine?

Any other concerns I should have? I expect the weather to be hot and the altitude to put a drag on the engine.

Thanks.

-Charles

Mr_Shiftright

Overheating is rarely a problem with a 300D. As for altitude, you will have a serious problem and so you'll have to remember to always shift manually and to floor it in first gear.

As for the trip up, if you leave early enough in the AM you'll be through the Sacramento heat before it gets outrageous and once you reach the foothills, it shouldn't be a problem for you.

Best thing you can do is make sure you have no coolant leaks in the reservoir tank, tighten all your hoses, make sure the cooling fan is working and plan to be in the right lane climbing up there. Are your emergency flashers working? You'l probably need them as you may very well drop below 40 mph going up the mountain.

doorcube4

Hey Mr. Shiftright.
I've got a window that has an engine that works but just will not roll down or up. Ive wiggled it back into the right position before, but I think that it is the "window regluator" as I saw you call it that might be broken. I've also read from your posts how to remove the door panel. The second issue is that since that window has been acting up (since ive owned the car its been a fickle window) I tried locking the door a week ago (I attempted to unlock the door from inside momentarily after locking it) and the door lock knob fell flat level with the door panel and is no longer attached. I can see a springesque figure inside the door knob hole. The door is now locked and the door handle from inside feels to be "jammed." It also cant be unlocked by key from the outside.
Any chance the window has caused this? And also where do i need to look inside the door to solve this?
Thanks!
-Glen

Mr_Shiftright

Yeah, definitely time to pop that panel. But if the door is locked from both sides you have a major problem...I hope you can open it from the inside.

Can't say if the regulator is screwing up your door lock release or not...there is a rod from the door handle to the door lock that could be jammed up.

Probably you will find the regulator snapped in half. You can order a new one from the dealer or maybe the Internet. They are aluminum and if you have a buddy to help you put it in, all the easier.

good luck with it

doorcube4

Thanks.
I fished that rod from inside the knob hole and so the door opens now. I plan on popping the panel, and im almost positive the regulator is shot so I now have a plan of attack. And the window and the door being locked arent related.
Thanks for the help.
Glen

peter64

I have a 1985 300D Turbo Diesel Mercedes. When I went to start it the glow plug light didn't come on and it would not start. How do I test the glow plugs and the relay. I have a voltmeter. I pulled the glow plug, plug, in the relay and checked it for resistance and got a reading on all five. I was surprised to get a 12 volt reading at the pins in the relay with the key off. Is that normal? Also, should I replace the plugs and relay with the Bosh Fast glow Kit? I live in New England and have not had this car long, so don't know its history. Any help/suggestions would be apppreciated.

Thanks,
Peter

Mr_Shiftright

You might check the glow plug relay fuse.

You can also run a hot lead from the battery to one of the glow plugs--it might kick off on just that one cylinder. If it does, or acts like it wants to start, at least you know that the plugs aren't getting any current.

Be careful, those plugs get HOT.

Glow plugs should be replaced every couple of years.

peter64

Thank you for the suggestion. I checked the fuse and it is OK. I don't believe these glow plugs have been changed in a long time so Im going to buy the Bosch Fast Glow Kit #0 250 201 953 which includes 4 plugs (I need one more) and a relay.

Peter

brakeengr

I am trying to remove the passenger side fresh air intake cow- the shiny silvery thing with net that is on the outside near the wipers. I need to see if it is clogged since I have water coming in the passenger side footwell, and it may be entering thru' the firewall if the clog does not allow the water to drain out.
But I am having trouble removing the cowl- there are 3 small black plastic square things that must be removable; but I don't want to force anything.
any idea on how to remove the cowl?
Thanks-

ewvdt

In the center of each of those "hold downs" is a black plastic pin. Just push that one down and it will unlock it. After removal of the screen you can fish them out of the air dam.

brakeengr

Thanks! that worked, and I have the cowl removed. There was no debris or blockage inside, so I guess the water is coming in from someplace else- I'll have to figure it out- maybe the windshield rubber...
Thanks again!

Mr_Shiftright

One thing you could try is some LATEX black caulk...apply with a wet finger and work it under the windshield gasket, then wipe off excess with water...just as good as silicone with none of the mess! Most suspect area is the gasket material in the very corner of the windshield==the gasket tends to shrink.

brakeengr

Thanks for the suggestion. I carefully poured some water from a container on that windshield corner, and it did not leak inside- so that was good. Next, when I had the cowl off, I poured water into the scoop, and it still did not leak inside. When I poured a whole bunch of water all inside the cowl, sure enough water leaked inside. Just by coincidence, I was doing this at night, and shining a light trying to figure it out- when I was looking under the wheel behind the mud-flap (had taken the mud flap off), my wife saw light coming inside from a small pinhole- this pinhole was right next to a screw that holds the mud flap.
So finally, I think this must be it- will patch it up and test tonight!
Thanks! Maybe I'll still do the black caulk because there was a slight shift in the windshield gasket.

goldcar

I got delayed a week somewhat due to the recent fires up there. I plan to head up to Tahoe this weekend.

Last weekend I went up Mt. Diablo in the 1982 300D turbo and the car performed well the whole way up. However, once I reached the summit and shut-off the engine, the coolant came pouring out of the reservoir tank. I ended up having to add about half a gallon of water later to refill the reservoir.

What can I do to avoid this problem and is it symptomatic of a larger problem?

Everytime I visit the auto parts store I notice all these "miracle" products to lower the temp of the coolant or oil. Are any of them worthwhile?

Thanks for your advice.

Mr_Shiftright

Well Diablo is no small hill and in 90 degree heat that's somewhat of a strain for an old cooling system. Yes the "water wetters" work--I like Redline products.

Might be time for a cooling system flush. 300Ds are not generally prone to overheating. You might also check your radiator for road debris, check your tire inflation, and make sure your transmission fluid is up to the mark, as the transmission is also cooled by the radiator...so if the trans gets hot, the radiator has to work harder.

goldcar

I have a new radiator on the car as of 2 months ago.

Last night I went out and purchase some redline water wetter. The guys at the store were nearly raving about how good this product is.

I added it to my coolant reservoir. How quickly will it mix in with the rest of the coolant?

Mr_Shiftright

I think 10 minutes on the road would do it (after the thermostat opens up I mean).

goldcar

It all worked wonderfully. I was even running the air conditioner on the way back. The temperature needle never moved above 100C.

Once the car is up to highway speed, it roars along almost regardless of the altitude. When I cleared Donner Summit, 7227 feet, I was moving along nicely at 65-70. However, a little while later when we got off the freeway and I needed to stop and then start, wow, it was slow.

Thanks

Mr_Shiftright

Yep, that's exactly how I remember it...once you get that heavy car going, it's okay, but god help you if you have to stop and restart going up a mountain. And once in the right lane climbing a moutain, you'll never have enough power to get into the center lane. You run with the big rigs going uphill in a 300D.

slugworth

My mechanic tells me that the injector return lines need to be replaced on my 83 300D turbo because they are leaking. I can't wait for him to do it so I was thinking of doing it myself.
What parts do I need? I looked at the benz bin and they have several different hoses - it looks like there are coils of hose and then precuts.
Any tips on doing this?
And motor mounts - I am not sure where they are but I have heard from two mechanics that they need to be replaced? What is the process for this?

peter64

OK, I found the problem. There is a ground wire in the relay that is in the wireing harness that had lost it's ground. I couldn't figure out where it went to so I just grounded it out to the body.

Peter

dpotter1

my 1979 300d wont accelerate using the foot feed. the motor revs but it doesnt speed up over 30 mph.
however if i use the cruise control the car will get up sa fast as i want it to go. what is the problem

burdawg

Could be the cable. The cruise control actuator has a different cable.

Mr_Shiftright

Yeah sounds like the gas pedal linkages

dpotter1

then why will it let me accelerate to about 30 mph

Mr_Shiftright

stretched, broken, blocked, something not allowing full travel.

burdawg

Ditto.

biodegrading

I've got an '83 300 SD. When I bought it about a year ago, my mechanic said the radiator ought to be replaced, so I went ahead and as my first-ever car repair project, replaced the radiator, thermostat, water pump/housing, and all the hoses (except those that run to the heater). I was very proud of myself, except that the car now immediately started to overheat once I was done! My mechanic looked at it and said "there's not enough flow--look at the water pump." So I yanked out the water pump, and, sure enough, I'd been sold a defective unit: the flange on the top of the pump stuck out too far, and was wearing away at my water pump housing. So I returned the pump/housing, and installed new ones. But I'm still seeing the car get up to 100 degrees or more. It actually appears to be worst when I'm not driving fast (for instance, while I was teaching someone to parallel park). The electric auxiliary cooling fan comes on, and the car just seems to be hanging in there at 100-105. Today I saw it at 110 when idling after doing a bit of city driving.

I've thought of doing a radiator flush--in particular, when I replaced the cooling system, I never opened up the bolt on the side of the engine that allows the coolant there to fully drain (the damn thing was too hard to reach!). I've also considered using some sort of radiator/cooling system cleaner, since I suspect there's some kind of buildup/blockage inside my engine. But my mechanic says I should probably just let it go, and that it's fine so long as the temp never gets to 120.

Any opinions on what I should do?

Some other facts:

The bottom hose coming out of my radiator is almost always cold, or at least vastly cooler than the top hose. If I shut the car down and touch the radiator with my hand, the top is toasty, but the middle and bottom are fairly cool. There's definitely some flow, though, as I've driven the thing on the freeway up big hills, etc. and the temperature stabilizes at about 100.

I've done some obvious tests. Water poured into the top of the (brand new) radiator drains out the bottom, no problem. I can also pour water into my engine block where the thermostat attaches, and it comes out the water pump end (though I haven't tried doing more than a dribble's amount of water at a time). The (new) thermostat opens right up starting at 80 degrees (I tested it in a pot on my stove). The flow through the heating system appears to be good--when the car is hot, and I turn on the heat inside, it blows very hot, and stays that way, and the engine temp drops some.

Is is worth a cooling flush and/or some radiator cleaner?

Sorry for the long post--this whole saga has actually lasted almost a year. It's been quite demoralizing as my first car fixit project.

Thanks!

ewvdt

make sure your thermostat installed correctly and not reversed.

Mr_Shiftright

Yeah, cool at the bottom of the radiator suggests that.

You could probably run it without the thermostat for a short time and see what happens (don't ever do this with a modern car, however).

biodegrading

I'm basically positive that the thermo is in the right way--I actually have replaced it twice, and once asked my mechanic to make sure it was in the right way. The coil is toward the engine block, etc.

I may try removing the termo just for the hell of it, though. Any other thoughts if it is indeed in correctly?

thanks.

Mr_Shiftright

Some are marked with an arrow that indicates the direction of water flow.

When you have a tricky problem, assume NOTHING, not even that something out of the box brand new, is good, or that the word of another person is gospel.

You can also have the radiator "flow-tested" at a radiator shop...maybe somebody screwed it up. Is it a brand new core or a "rebuilt" or ????

Are your hoses very soft. Could they be collapsing when you rev the engine?

biodegrading

Hoses are brand-new. Sure, they're a little soft. I'll have my wife rev the engine and see if they collapse. Any hose in particular likely to be the culprit?

And I'll try taking out the thermo.

The radiator is supposed to be brand-new. It certainly looked new.

Any opinion on the radiator cleaner products? Do you think it's likely that something in the engine block pathway is blocked? I did leave the engine block open (no hoses or water pump, etc) for about four months while I resolved the whole water pump saga. Rust?

Should I be making so much fuss over running at 100, and occasionally at 110?

Thanks!

lydia2

Have you checked all the filters? I had this problem with my 83 300D. Went fine at hightway speed on a long trip home; then in the city at a stop light, hardly got going at all, maybe only 30. Next morning, it was almost normal again. The transmission or fuel filter, forget which, that needs changing every whatever (5000k) was so dirty. Changed that and everything was fine. It had taken all night to drip through the filter. Lucky I didn't get more damage. Guess I should check my papers and find which filter and when? Can't find that info. Maybe "Shiftright" or Burdawg can send on this information for me. Thanx, good luck.

burdawg

You must be referring to the fuel filter, but changing it every 5K shouldn't be necessary, unless your getting some really dirty fuel.

lucke113

I am seriously considering buying a early to mid 80's 300D. I have never owned a Mercedes before but I love the style of that era. I would like a diesel, so I could run biodiesel(do my part to save the planet).
I have read through every post in this forum and have an idea of some things to watch out for when making a purchase. I do have concerns after reading some of the posts ie: cost for repairs.
In this forum's collective wisdom, would this be a reasonable purchase for a mom who will use this to run to town and back and an occasional 250 mile trip, are they reliable enough?
I don't plan on spending more than $5000 on one and it will be one I have thoroughly researched.

I thank you in advance for any comments/suggestions.

texases

Will this be your only car, or will you have reliable backup?

p.s. - It's OK if you like the styling, but recognize that the diesel version would be one of the most polluting vehicles you could buy.

lydia2

Thanks. Found my papers. It was the transmission filter. The first guys just topped it and this didn't work. Then I got a new transmision filter and the problem has been solved. I was told to change it ever ???km, but my odometer hasn't worked since forever so I do it about every 5 years and so far this has worked fine.

lucke113

This would be my main mode of transportation. My husband has a '06 Chevy Silverado but we go our separate ways everyday.
Would the biodiesel be as polluting as regular diesel?

I am also considering the VW Passat. I need reliability and something more economical than my Yukon. I also need a 4 door, as I do still have 1 in a car seat.
thanks

texases

Biodiesel might be slightly better, but I have bad memories of the smoke put out by every 300D I've followed. Another issue is performance - you might be disappointed by the day-to-day acceleration (or lack thereof) of a 300D. Have you driven one? Finally, are you or your husband big on car repair? As you've noticed, these cars require constant upkeep, which is fine if that's what you're expecting and enjoy, but not if you're having to pay a professional. Sorry to be somewhat negative, but you need to consider these issues, especially if you've set a $5000 budget, which will limit your ability to find one that has been well-maintained. They're in high demand these days.

p.s. - I'd wait for Shifty and Fintail to weigh in - they're better sources than I. I did look on Ebay, they're all turbos as far as I could tell, most with > 150,000 miles, so maintenance records will be important.

lucke113

Hey, thanks for all the advice.
My hubby is pretty handy but foreign cars are not a specialty, nor do I want it to have to be.
I am not limited to $5,000, I am selling my gas-guzzling Yukon XL and would like to purchase a car AND have $$ to put towards getting my advanced degree. So, the less I spend on a car, the more that can go towards tuition!
I have also considered a VW Jetta/Passat or a Land Rover, both late 90's models?

texases

I get the feeling you're not a Honda/Toyota person. I'd stay far away from the Land Rover, but a Jetta (kinda small) or, preferably, a Passat (great looking car, should be able to find one that's been well maintained) would be good - could even get a wagon.

lucke113

Yeah, the Passat would come before the Jetta.

What about Audi's. Seems like people either love 'em or hate 'em. I have read some horror stories but then you can find that with most vehicles.

Toyotas and Hondas are great cars, I had a 4-Runner for 8 years...loved it. I am ready for a car but don't like the "gramma" Camry and the Accords seem to be blah as far as styling goes.

texases

More horror stories w/Audis than most, I'm afraid. While they have certainly improved from the dark days of the 1980s, it's better to avoid. Some of that rubbed off on VW (many shared parts) but still VW would be preferable. I had VWs '81-'96, enjoyed them. One option - how about a Lexus ES300?

fintail

I don't know so much about diesels, but I wouldn't advise anyone to press a 25 year old car into daily service unless they know how to turn a wrench now and then. These old diesels are indeed very sturdy, but at the cost of constant maintenance. If you don't mind working on it, go for it.

For nearly every other period car, 5K should be enough for a pristine example, but some of these dieselheads are insane. Shop around, spend some time looking before you jump. Find a good specialist and have an inspection done before you buy. At this age, make sure the suspension is sound, as well.

Mr_Shiftright

I'd get a Passat if I were you. A 300D is a "hobby car", really. If you get a 1.8T Passat, be sure to have it checked for engine sludge and get maintenance records.

lucke113

Thanks for the advice. I always do my homework!

texases

Yes, the VR6 would seem to be less troublesome.

brillanze

Don't spend anywhere near $5000 on an 80s Mercedes. I have a 1983 turbo diesel and I love it. I have done minimal maintenance on it and I drive a lot. I do need a new a/c compressor, which will be expensive. But, I bought mine at a charity auction for around $500. I have seen 1981-1985 advertised in the Dallas area for around $2000-and these were in very good shape. I certainly wouldn't spend more than $2500. And mine does smoke, but just at start-up. Good Luck.