Mercedes 300D Suggestions

waxuras

My 300d is doing the same thing. However now mine won't turn off! I have to open the hood and hit the stop switch.

Did you ever replace? was it hard?

ewvdt

The shut off solenoid is vacuum activated and controlled with your ignition switch. The solenoid might be bad, also. Even the vacuum pump. First check all of your vacuum hose connections under the hood and at the switch.

waxuras

Yeah you got it...and thanks!

I got a oil change and since then it started.

Also the door locks won't go down..so it must be that.

I just need a good map for all those hoses!

burdawg

I've said it before and I'll say it again, a set of FACTORY manuals is invaluable for these cars. Your going to save yourself a lot of frustration and trouble, and in the long run they usually pay for themselves in time.

Mr_Shiftright

Sometimes they can pay for themselves in one repair.

rangner

If you get the service manual on CD it's even cheaper. I bought one off of ebay for $55 including shipping. I use it for everything. Just print off the sheets you need for each job.

rangner

What do you all think is a reasonable amount of time to idle a turbo diesel to cool off the turbo?

I use rotella T full synthetic 5w-40 oil so I might not have to worry about coking the turbo but...

With diesel so high I don't want to idle unnecessarily, but at the same time I don't want to shorten my turbo's life.

goldcar

I am looking for a 1982 300D factory manual. Is this what you mean, Mr. Shiftright:

http://www.manualsunlimited.com/product_info.php?cPath=46_70_135&products_id=118- 53

Mr_Shiftright

No, that's a CD. You don't want a manual on CD--and this one doesn't even give you a clue as to what's on it.

I'm thinking of the three-volume set--Engine, Chassis and Maintenance---they run about $300 I think.

92tdiesel

I posted a few weeks back about trouble with my tachometer and my ABS. Formerly, my tach would die out randomly and the ABS light came on. It would last for a few seconds, then would go back to normal. Starting this weekend, after I changed my oil (Mobil 1300 Super), rotated my tires, and replaced a dead fog light and side marker, it would randomly start the buzzer as I was driving. This lasted about two days with no other problems. Today, I started the car after class, sat around for a few minutes to let it warm up, hit the brake and all the guages died and the buzzer came on. The engine ran fine, the speedometer still works (better than it did before), but the buzzer was very weak (barely audible).

I have no idea.

I can't afford to pick up an entire set of manuals, nor can I bring it to the dealership (I've yet to find some shadetree guy who knows these cars in Upstate NY). All the fuses are intact and it gave me no trouble driving 4 miles back to my house from school. The faint buzzing would stop when the blinker went on. This is a '92 300D... does anybody know where I should start looking to solve this???

92tdiesel

That was bright. I realized this morning that the brake lights aren't working... this was all on the same fuse as my tach, guages, etc. As I was heading out of my car, I remembered someone telling me once that the fuse won't always burn up on the small strip, it can burn elsewhere. Sure enough, the top cap was burned on fuse 5! Sorry about that, guys. Things are fixed now...

dougflyak

Help please! I have a 1982 300CD. I think there must be a vacuum system problem since I have the following symptoms. The engine won't quit running when the key is turned off. The trunk lid won't open, it's locked and I don't seem to have a key that opens it. The ignition key doesn't do it. Is that normal? I have another key that came with the car but it doesn't work either. The heater/defroster routing valve doesn't work any more. (that's also vacuum actuated)

This all started after I was working on the passenger side door lock mechanism. It looks like it was previously worked on and I had to make some adjustments to make it function properly. The vacuum actuator for that door lock seems to work OK. I even saw it lock when I locked the driver side door. (That's when the trunk lid locked and now it won't unlock.)

The power brakes work fine. I disconnected the main line from the vacuum pump and there is plenty of suction.

Any idea how to open the trunk lid? How do you trouble-shoot the vacuum system for leaks? There seems to be miles of vacuum tubes in this thing!

Any help would be appreciated! Thanks

Doug

brakeengr

for opening trunk- on my 300D also, I have disconnected the vacuum to door locks and trunk, and open them manually. I cannot explain properly in words, but for the trunk you have to kinda jiggle the key and press the knob at the same time- you will feel the difference when the key has been turned properly and the knob is pressed. If the key is not turned properly, the knob will just loosely press, but when the trunk is ready to open, you will feel a more solid pressing of the knob.
I don't know how else to explain.
Assuming you have the original key....
The original ignition and trunk key are the same.

zadams

hello,
this is a reply and a question. I own a 1985 300D (also called a TD) with a vacuum system. While converting the car to run on waste veg. oil, I removed some of the vacuum hosing that was brittle and fractured. I experienced the same problems (no shut off, locks malfunctioned, etc .) From what I understand of my 300 D and assuming the vacuum systems are the same for both vehicles, it is without a doubt the vacuum system that is your problem. There is a fuel shut off diaphragm that is controlled by vacuum pressure, and the locks (including the trunk and fuel door), and the transmission, and a few other things are all tied into the system. You do not want the problem to persist by just making the locks manual and opening the hood and using the choke every time you shut down. For one, the transmission does not function properly and it may lead to irreversible damage from what I understand. I would suggest checking all of the tubing and connections under the hood first, look for cracks and feel around connections while the car is running for a bit of air leaking from all connections (it may be sucking or blowing). Putting a bit of veg oil or water on a suspected crack or loose connection might show some bubbling and confirm any suspicions. If the problem is not there, then your life just got complicated, because there is a lot of tubing imbedded in and under the car that requires a jack and removing some door and other panels.

if you can get your hands on a vacuum system diagram, then by all means use it. I have a CD manual and it allows you to access the Mercedes Benz online library. Unfortunately, I have not been able to track down a complete vacuum system diagram to help me re plumb my entire front end.

IF ANYONE HAS AN ELABORATE VACUUM SYSTEM DIAGRAM FOR 300 SERIES, OR KNOWS HOW TO LOCATE IT IN THE MB ONLINE LIBRARY, PLEASE RESPOND TO THIS POST. THANK YOU VERY MUCH.

I hope this helped,

zak

ryan77300d

Here's a great diagram of the entire car, 300D Sedan and 300TD Estate.

http://mb.braingears.com/123_DISK2/program/Chassis/80-900.pdf

-Ryan

burdawg

You can tell that those pdf files are right out of a MB factory manual. The format and drawings are always very well done, clear and concise.
It's like buying an IBM workstation or server class computer, the manuals always look the same and have an almost overwhelming amount of information.

fintail

Those old exploded parts diagram books included with old MB are pretty cool too.

zadams

thanks,

I appreciate the help and support. I believe I can track those diagrams down in my manual if I look hard enough. I'm slightly confused though. The diagram seems to have some of the vacuum elements of the front end, but not all. I do not see the fuel shut off diaphragm in the diagram for example, and a few other things. Can anyone explain this? Thanks.

zak

lrccole

My 1985 300SD continues to run when I turn the key to the 0 position. I can manually cut it off under the hood, but when I start it again, it won't cut off. Help?

zadams

you may want to search the last thread on this, the fuel shutoff diaphragm is most likely not working properly. assuming your SD has a vacuum system, then it may be a problem overall with the vacuum system, because the fuel shut off diaphragm is controlled by vacuum. so the follow up question is, is anything else not working properly (door locks, trunk lock, gas door, tranny shifting roughly). if so, then there is a problem somewhere in the vacuum system and the entire system is not functioning due to the pressure loss (most likely a leak somewhere in the system). if nothing else is wrong, then the vacuum system may be fine and just the fuel diaphragm is broken. this may be the actual diaphragm, or it may be the relay that triggers the diaphragm (located on the firewall), or the air tube from the relay to the diaphragm, or the wiring from the ignition switch to the relay. write back for more specifics after the problem is narrowed down.

AGAIN, ANYONE HAVE COMPLETE SCHEMATICS ON THE VACUUM SYSTEM FOR A 300D, 1985? The one at giant diesel is incomplete btw.


zak
1985 300d, 180,000, veg oil converted

slugworth

hello-
I am looking at buying a 1983 MB 300D and need some advice. It has around 250,000 miles and I can get it for around $1000. What signs would indicate that it isn't worth it? Is there anything specific that I should look for? I have done some minor maintenance on cars, but don't know much. If it starts, should I bother with an $80 purchase inspection? I need a car, and while i have been looking at Toyotas and hondas, this one caught my eye and now I am having fantasies of having a mercedes. My dad had a 1973 280sl that was a lot of fun . . .
any advice?

Mr_Shiftright

By all means get a purchase inspection! You could blow another $3,000 on this car in a red hot miniute if it isn't any good.

Things to check for SURE:

1. Climate control system...does the heat/def work when you dial it in?

2. Does the engine start like RIGHT NOW when you crank it. If you have to crank and crank and crank, that's a real bad sign on a diesel Benz

3. Are the rubber boots ripped on the rear axle CV joints?

4. Do all the gears (4-speed automatic) shift VERY firmly and when they are supposed to?

5. do the brake rotors have deep grooves in them?

6. Does the car puke clouds of black smoke when you step on the gas quickly?

7. Try all the window switches, lights, sunroof, etc.

As for rust and cosmetics, you can't expect much for $1,000.

zadams

it depends on what you want: if you want a drivable car that's reliable, then you need to find out a few things. Is the car currently inspected, and if not, can it pass inspection? if it is inspected, for how long? A car with half a year's inspection in decent condition is worth a grand. but the path to inspection with a old benz can be a long and expensive one. (i happen to be doing it right now and it's not pretty) parts are not cheap and specialized labor is even worse. if the car has 250,000 on it, how and where were these miles put on it (you may not be able to ascertain this, but if it is city miles, especially in the north, and not garage kept, you might as well forget it). a well attended benz engine can live well past 250,000 though. Does it have the original tranny, timing belt, injectors, brakes are definitely good to check, but not a huge deal to fix. Look under the hood and check for oily spots or wet looking spots around the injectors and valve cover and head . see if the car runs hot, could be a sign of a failing pump, which is a big problem as far as money goes. look under the car at the exhaust for rust and holes. look at the transmission for leaks as well. you should pay for the inspection if you don't know what the things I just mentioned are and where they're located. frankly ask the seller what the problems are now, and repost with them, others may know symptoms of larger problems. most of all, good luck and feel free to ask me any specific questions about running your diesel benz on bio diesel or waste vegetable oil (wvo).

z 1985 300D 180,000 - 5,000 veg oil converted

92tdiesel

Just to comment on Mr. Shiftright's point #4:

The transmission in these shift very firmly. It shouldn't clunk or give you whiplash, but Mercedes didn't design these cars like they do today. You'll definetly notice the shift, but it should hit at the right time. These diesel engines aren't made to run at high RPMs and they'll shift pretty quickly.

As he also mentioned, climate control, ELECTRIC, vacuum, and rubber boots are usual problem spots. The rest of the car, especially the drivetrain shouldn't give troulbe unless you don't keep up with it.

They're safe, economical, "classy" (go easy when pointing that word to these ones), comfortable, etc. etc. My coworkers are SICK of discussing that car (especially when I brag about my miles)!

slugworth

thanks to everyone for their responses. it was very helpful. I imagine you will hear more from me later - I bought it and it seems like a pretty good one. some work to be done but nothing too serious. my friends are jealous.
now - what should I expect to pay for a right taillight assembly?

Mr_Shiftright

Oh go to eBay for that or a wrecking yard. Amazingly, there were a GAZILLION of these cars sold in the US and they litter the landscape of boneyards and people's garage parts bins. I'd expect $35 to %50 would be more than enough for a used assembly. They are easy to install....just take off the 4 or 5 round white plastic nuts on the interior side of the assemply, and push it out. I'd also recommend you re-seal the assembly using a LATEX caulk (water-soluable) so that you don't get water in the trunk.

Good point about RPM---these engines are NOT meant to run at high RPM....80 or 85 mph is all you should ever attempt.

Constant hour after hour extreme high speed operation will crack the cylinder head sure as shootin'. These are not Peterbuilt tractor trailer engines.

slugworth

Yeah - I already have water in my trunk. Thanks.
Next to fix is the Tachometer.

tech6

Hi,

I have an 85 300DT with door locks that lock and unlock themselves. How do I disconnect the vacuum lines to just the door locks?

Also, how often should I be changing the oil on a turbo?

thanks,
Peter

Mr_Shiftright

You can pop the door panel off...it's pretty easy...just remember after you've loosened the bolts for the armrest and removfed the door opener trim and popped all the plastic snaps off (which will break so have new ones ready), that you lift UP on the door panel....don't pull it straight out.

At the bottom of the door you'll see those cute little vacuum motors.

Be sure to plug the vacuum lines if you take them off, and I think you can disconnect the rods from the vacuum motors, which will make the key turn easier.

OIL CHANGE: You mean how often to change the engine oil? I'd do every 3,000 miles

brakeengr

I did not have to open any door panels to disconnect vaccum to the locks. Mine is a '82 300D, but under the hood just in front of the firewall driver side you'll see a bunch of vacuum lines going from a splitter. I'll have to check, but I think the yellow is for the locks- just unplug it from the splitter; make sure the splitter end is capped so the other lines don't get affected.

Oil- yep- as Mr. Shiftright says, 3000 miles is "normal"- but I put the good synthetic stuff, and go upto 5000.

frangovam

Hi, I'm new to this forum, and I've been reading these messages for the past few days. Some really interesting stuff you guys have posted.

I bought a new 1982 300D turbo for $3400, which seems like it might have been overpriced, but I'll let you guys decide.

- 164000 miles.
- No rust that I have found myself, except for a piece on the trunk lid under the "300D" (right where the rubber piece is). And there is some on the bottom of the inside of the door (2 of the doors).
- When I go over speedbumps, the shocks make a slight creaking sound.
- It drips oil quite a bit (I assume it's quite a bit... about 4-5 drops per stop). By "stop" I mean when I turn off the engine for 2-3 hours. The front underside of the car seems to have a bit of oil on it.
- My auto door locks do not work.
- Heat and AC are just fine (considering what I've read in previous posts). And yes, it takes a minute or two to kick in.
- The paint job is okay (a bit of fading) and it's a nice charcoal.
- The interior is a bit ripped up in places, most noticeably the material on the pillars in between the windows.

By the way, excuse my made-up terms for different car parts... but I know extremely little about cars. To continue:

- The back driver side window makes a "thump, thump, thump" sound when it reaches the top and I'm still holding the button... the other windows DO NOT do this.
- Brakes seem good.
- When I flick on my brights, the lights turn off... I found this out going 65 on a dark highway in central South Florida... scared the crap out of me. I had to resort to using regular lights, plus fog lights... worked well enough, but I'll have those brights fixed.

So tell me what you guys think, and please, any suggestions on what I should do next would be greatly appreciated. I will be doing my 1st oil change soon, but I'll wait to see if there are any replies.

FrangoVAM

peter64

Thanks a lot, I'll try it this weekend.

Peter

peter64

I like that better then poping off the doors. I'm going out to look for the splitter now.

thanks,
Peter

peter64

Anyone have a suggestion where I can get a vinyl covered, front, driver side seat for a 85' 300D? It's the 123 body which I believe is common from 78 to 85. I would go for a ripped one if the frame is OK and I can get it reupholstered cheap. The one that's presently in the car is a replacement that doesn't match the rest of the interior. I live in New England.

Peter

peter64

OK, I found the spliter. It looks like the lines may have been changed. I don't have a yellow one; just black lines with one which has a purple connector. Two of the lines go through the fire wall. I assume one is for the doors and one for the climate control (which also doesn't work right). Is there any way to disconnect what I think is the right line and test it? I guess I could just test the door locks to see if they work. Suggestions?

Thank,
Peter

Mr_Shiftright

There's a tool you can buy (or borrow) that applies vacuum like a little pistol that you squeeze.

I guess hit or miss is the best way, no harm done.

brakeengr

Make sure you do the splitter closest to the brake booster. Mine were 2 yellow lines- presumably one was for the locks and one for the trunk- I disconnected them both.
There were other green and brown lines also- leave them alone.

peter64

Thanks, I'll check it out tomrrow morning.

Peter

baccus49

Congratulation on your purchase.
A Couple of things I can tell you based on my'85 300D

With the mileage do be aware that the gears in the main odometer can under some circumstances be striped if you reset the trip odometer while the car is moving. Keep that in mind, as you own the car.

With the noise when you go over speed bumps, that may not be shocks. I just fixed my noises that I initially thought where shocks. So if you get a clunking sound in the rear when going over speed bumps that may be your rear sway bar links, I hear that can be a common cause for that clucking noise, changing those fixed the noises in the rear for me. In the front I had more of a squeaking noise that turned out to be the right ball joint that was about ready to fall out. My noises are gone now and I still have the same shocks.

With the door locks not working, that's common and it's going to be allot of fun to fix, your most likely looking at some sort of vacuum system problem either a leak somewhere or a pump problem. A good part of the car runs on the vacuum system and your window problem maybe because of the vacuum system as well, although I think your windows problem is something else. There are allot of article out there on troubleshooting the vacuum system, have fun.

With your interior something I may recommend, if your springs in the front seats are warn out, put pool noodles between them, I did that and it stiffens that back up check out: http://www.mercedesshop.com/Wikka/W123SeatRepair

With your high beam problem if you didn't mind you could probably hold the stalk out and the high beams would stay on, I just fixed that on mine by replacing the stalk, it is really easy (took me like ½ hour), I found an after market stalk for about $95 on a discount parts website - it works great now and I can run the washer fluid with the high beams on now.

Have fun with the oil change, your oil will probably be very black, that typical. I would recommend buying a box of latex gloves because it is very hard to get that black off of your hands. The other surprise you may have is the oil filter is a basket style (not spin on like most cars) and the canister is not placed in the easiest place in the world to get to.

peter64

Brakeengr

got it, thanks

Peter

brakeengr

You are welcome. Make sure you cap the open ends of the splitter when you take those 2 lines out- otherwise your other vacuum systems will be kaput!
I just took the hollow rubber sleeve, and put 1 end on the splitter and the other end on the other end of the splitter- so made kinda "U-turn"

Mr_Shiftright

In fact, your fresh clean oil will turn black about 15 minutes after you start the engine---that's normal on older diesels of this type.

Changing the oil on this car is a disgusting job and I recommend paying someone to do it. I ALWAYS get my filters from the dealer, no mickey-mouse oil filters for this car!!!
They may not fit correctly inside the cannister.

goldcar

Whenever I accelerate fairly strongly in my '82 300D and get to about 2000 RPM I hear a clicking sound coming from in the center front, maybe a little down and to the right. Because that is about the RPM where the turbo kicks in, I assume it is somehow associated with it.

What might this be? Should I be worried?

Mr_Shiftright

sounds like an exhaust leak to me, maybe where the header collects and connects to the exhaust pipe. Sometimes you can actually see a black smudge at the pipe connections that tell you that you have a leak.

Usually if a turbo itself is wearing out, it will whine very audibly and you'll also get a lot of blue smoke out the tailpipe when you start the car up. Of course with all that clatter from the engine, it might be hard to hear. I'd guess that ticking is also there at under 2000 but you just can't hear it.

goldcar

That doesn't sound too worrisome, then. There is no whine. I was worried that somehow when the turbo kicks in it might cause extra strain on some other component that would then make metal-to-metal contact and cause the clicking.

I'll ask my mechanic to take a look next time it goes in, but I won't schedule a visit just for this.

ryan66

I had the instrument cluster out to change entire lock housing. Didn't disconnect battery and a wire zapped something. I put everything together, found 1 blown fuse. Now everything is wacky, and I rechecked all wiring. The fuel gauge shows full, temp is high. oil pressure off.
Clock, radio don't work. 4 ways don't work. With lights on buzzer sounds when going from low to hi beams and the gauges move. Door locks don't work. Any ideas? THANKS.

Mr_Shiftright

Well if the turbo blades were hitting something it would pretty much disintegrate in short order---turbos spin at incredible RPMs..too fast to hear a "tick".

mdyoung1

GOT A 82 300 CD. PRETTY GOOD SHAPE. FEW QUESTIONS IF ANYONE CAN HELP
1- HAS A HARD SHIFT FROM 1ST TO 2ND
2- LOOSE PLAY IN STEERING/HAD MECHANIC TO LOOK UNDER AND HE SAID EVERYTHING LOOKED TIGHT.

Mr_Shiftright

1. Normal--the transmission are neck-breakers

2. An alignment might help this if the "play" is when you are driving. They aren't sports cars, so you are going to feel fairly leisurely steering

fintail

There's a bushing that commonly fails on fintails, and that creates a lot of play too. Fairly easy fix, and it's not in the steering box. Maybe a 123 is the same style. Have the whole steering system checked closely.