Mercedes 300D Suggestions

brakeengr · August 2005

Thanks! Yes, that's what i was thinking you must have done.
Great site on the instructions too- it gave me another thing to look at for my transmission shifting problem!
Thanks.

300cdveggie · August 2005

Okay, turning to benz #3, an '84 300TDT.

Starts fine, good power, cruising on the freeway at 80mph, get off the freeway and she barely runs and has no acceleration at all. Changed fuel filters had the valves adjusted. Took it to a mechanic who has done good work for me in the past. He says that there is an air leak IN the injection pump and I ought to start looking for a replacement. Has anyone heard of an air leak in the injection pump?

He told me that he test drove it, the symptoms happened, he pulled over, pumped the primer, saw the air bubble clear and it fired right back up with full power.

My first instinct is to replace all the rubber portions of the fuel lines, but he was pretty certain of his diagnosis.

????

hughes2 · August 2005

have had this problem , i live in outback Australia, alot of dirt roads, some times a small rock becomes jamed in rear trans mount, it vibrates so bad you thinkyou have a loose tail shaft or torque converter. some times dry mud builds up around mount and causes same problem . hope that helps!

hughes2 · August 2005

further 2 my mess. we have 3 , 300d's; in aust turbo not available, dec80 aust deliv 1,200,000 miles!!! 83 hongkong del 80,000miles, 84 aust deliv 200,000miles the 1980 one is on its last legs the body is a bit knocked around, have to set valve clearance every 50 to 100,000 miles otherwise wont start when cold ; inlet valves loose clearance & no comp!! We are haveing trouble with the 80 & 84 mods with slipping in trans for 2nd to 3rd shift , have to back of gas to let trans lock into 3rd. does anyone know ware I can find out detailed info on trans ,eg tech rebuild manual, can the fluid flow for 3rd gear be increased for faster change? Any one elce had this prob? its not vac valve related, been there done that !

brakeengr · August 2005

OK, my transmission shift problem is solved. It was not transmission vacuum valve or modulator. I had to take it in to the mechanic. It was debris and adjustments inside the tranny- he said there are many valves in there, and he had to clean them all up and adjust the shift points- cost me $400.
But holy cow- it purrs as smooth as a kitten now! The shift from 1st. to 3rd. is a little bit hard; I think not bad at all, but he said that is normal in a 1982 300d, and he had to do it so the later shifts are not sluggish. Shifts to 3rd and 4th are wonderful, and it cruises along at 2500 rpm mostly.
Great job, and anyway I got new fluid, new filter, and the tranny good for 200K miles more! (have 237K on the car).

2 questions:
1) I replaced the fuel filters and now see that the main fuel filter has diesel outside and the top of housing is kinda wet with diesel. The filter I put on is Fram. Wondering if the gasket is too thin? The previous filter was Mann- should I replace with Mann? I can also see the fuel gage needle dipping faster than it used to before- has to be the fuel leak from the main filter?

2) Second- any opinions on the high performance air intake kits that replace the factory air box? Are they as good as they are hyped up to be?
Thanks.

brakeengr · August 2005

typo in my message above- shift from 1st. to 2nd. is a little bit hard (not from 1st. to 3rd!!)

Mr_Shiftright · August 2005

1. Buy your fuel filters from Mercedes! The aftermarket ones don't always fit!! This goes for oil and fuel...the dealer's filters are only a couple bucks more.

2. Special drop in air filters are probably a waste of money for you--no drop in filter does any good whatsoever, unless you want to extend your air filter servic e by installing a filter you can oil. But no performance gains are going to happen with a simple drop in filter.

brakeengr · August 2005

Regarding air intake kits- I was not talking about just a drop in filter.
What I meant was the high performance air intake kit- that replaces the black round factory air box. Wade Performace Products makes such a kit; sells for $149. You take out the complete big black round air box. They provide aluminim tubes and associated stuff- one end is a cylindrical filter open all around to air; and the other end, tubing goes into the turbo. The claim is there is lots more air going into the engine, breathes easier and performs better.
Go to www.wadeperformanceproducts.com to see what I am talking about.

Thanks for the fuel filter advice- I'll do that.

shootingguard7 · August 2005

wow this is a great conversation. i was wondering if there are any modifications i could do to my '82 300SD. It has over 300K miles on it, but it still runs like a champ! I would like to boost the acceleration in some way. thanks.

Mr_Shiftright · August 2005

I don't think it would make a bit of difference on a diesel...if you follow your original air filter it goes right into the upper grille...how much colder air can you get than that?

Besides, diesels work on constant air flow and variable fuel flow. All I see here is $149 flying out your driver's window. At best you might gain a handful of unnoticeable HP at very high rpm.

These systems can work (to a degree) on gas engines that have restrictive air boxes, but I don't think either case applies to your car.

brakeengr · August 2005

Thanks. My mechanic didn't think much of it either. So I guess that conversion is out!

Mr_Shiftright · August 2005

It's very difficult to make blanket statements about these induction systems...I've seen cars on dynos with these systems installed and some do gain a few HP, some make no difference and some actually lose horsepower. You just never know until you do the dyno tests. Mostly I look at the stock system and the type of engine that's in there and try to draw some likely conclusions from that.

Besides, a car engine is really part of a long tube...there's the mouth, the guts and the....other part out the back. If you aren't addressing the whole system, I don't think you are going to get very far.

brakeengr · August 2005

You're right- engine is a part of the whole system.
And my car is running just perfect- not having any problems; in fact I think it accelerates quite well, and I am happy with it. But diesels do like air, and compression ratio being high, I was thinking if the kit helps get more air in it, there would be less blow by maybe, more efficient use of diesel, and increased mpg. I'm sure the Germans must have thought all this many times over; so why mess with something if it ain't broke!! I'll just keep the air filter clean!

Mr_Shiftright · August 2005

The system I saw in the photos looks WORSE than the stock system--it's taking hot air from the engine compartment---your stock system is at least sucking it through the grille. Besides, the general rule is 1% horsepower gain for every 10 degree drop in air temperature, so what are we talking about under the most ideal conditions? Exactly----not very much.

hughes2 · August 2005

thanks for your comments about transmission clean out! sounds like you found a mech that actually knows something about MB trannys ; a very rare person !! over here all they want to do is do a rebuild!! thanks again !!! Edmunds provide an exellent service here pitty I cant use them for biz things to make it up to them!!

brakeengr · August 2005

Yes, I am very happy with my mechanic. He is fair, doesn't do things that are not necessary, and actually solves the problems. In one instance, I wanted shocks replaced because of squeaking noise from left front- he checked, said not necessary- instead replaced a linkage bar at the wheel- problem solved. I consider myself lucky; regular maintenance items I can do, and for bigger jobs take it to him!

Mr_Shiftright · August 2005

I think the people who have contributed to this forum have been just outstanding. You all have a good sense of what "online community" means. I've learned a lot myself here too!

Shifty the Host

mercedes300d · August 2005

Hi, I am new at this forum. maybe some of you can give me some help.
I have a 1992 Mercedes 300D Turbo Diesel which recently started with problems on the transmission. It works fine on D position, but on Reverse it takes about 4 or 5 seconds or even more to start moving, and then the reverse shift enters very smothlly and slowlly. When the car starts moving on rear direction, it makes a strange noise like vibration or jerking, till it finally stops the noise and starts working fine. Other thing is that if I press the acelerator down to increase speed before the reverse shift is completely engaged, the car jumps a little before it starts runing right.
I remember I had some problems before with the transmission of the same car and the problem was a vaccum valve that was in stock, do any of you have had a problem like the one I have? Remember that my problem is only in Reverse position of the shift.
Thanks for your help.

pselaphid · August 2005

Greetings, I'm new:
Car is an '82 300 TurboD, converted to run on used veg oil (dual tank, in line heater). No previous eccentric behavior in brakes. Sat. I drove 35 mi. About midway, after accelerating from a stop I noticed a strange vibration that made the rear view mirror vibrate noticeably at 60 MPH. I assumed the worst (car about to fly apart) and was about to pull off when it diminished then went away. Upon arrival I did a walk around and found the driver rear wheel and rotor badly overheated, i.e., spit test produced sizzles.

Next morning's return trip was uneventful, with no excessive heat on that wheel, though I drove slow and tried not to brake much. Short trip to work today normal.

So, I'm trying to figure what, if anything, to fix before embarking on exploratory surgury. I had a similar problem once on another car that was a swollen flex brake line preventing fluid return. Also, and this is a long shot, I drove through some road oil/fresh tar last week, and it ocurred that some might have dripped onto the pads and caused the transient sticking before getting cooked off. Other ideas?

And this followup to a recent post; I bought one of those "performance intake" packages sold on E-bay that was mentioned recently, and can point out some problems. The "K&N style" air filter is a cheap knockoff that doesn't perform well. I was notified of this by a disgruntled user and can confirm, after checking, that the filter lets fine grit into the intake, a VERY undesireable feature. Fortunately, I didn't have it installed too long. I trashed it and bought a legitimate K&N after spending quite a bit of time researching size requirements and getting one that fit the intake pipe. Also, the breather hose to the oil scavenger and intake was too small on the original and that also required a lot of retrofitting. I understand he has this fixed, but I think he is still selling the substandard filters. As for performance, seems about the same, but it does make the engine look good. and things on that side are easier to get to.

Hints about the brake malady are appreciated.

Mr_Shiftright · August 2005

Your post isn't clear. You got the vibration while accelerating, or while braking at 60 mph or ????

Spit test doesn't mean anything. Brake rotors get VERY hot in normal operation anyway. Best test is with a pyrometer, then you have a number relative to other rotors.

Anyway, vibration while braking means a warped rotor, and it's not going to un-warp, so if that's what happened, that's one problem you have. What CAUSED the warpage is another issue.

If you got a vibration while ACC-elerating, that's probably a wheel balance or bent wheel or driveshaft issue, but again, those things don't just go away.

pselaphid · August 2005

I need to add another detail regarding the previous description. After the vibration phenomenon, I noticed that the brake pedal was spongy and non-responsive unless pumped, a sign of brake fluid vapor lock. Brake fluid level normal.

OK, that's it.

Mr_Shiftright · August 2005

When's the last time you flushed out the brake fluid?

pselaphid · August 2005

Thanks for the quick response. Vibration noticed after reaching highway speed, gradually worsened, then went away, but DID NOT return, either during completion of that trip or return trip, at speeds up to 60. That wheel and brake rotor were the ONLY one of four that was frying pan hot, others could be touched. Car has demonstrated no rotor vibration warpage even during stop and go city driving, when usually it is obvious.

pselaphid · August 2005

It'll have nice fresh brake fluid by next week!

brakeengr · August 2005

If your vibration is while braking, check your brake pads- how old are they? They could have debonded from the steel backing plate, or they could be all worn out so that there is metal to metal contact between pad/ rotor.
And get good pads like Mintex or Pagid. I can tell you the friction material makes a hell of a lot of big difference.
I had same problem, and my front pads were debonded.
Tip: If you change pads, put new rotors also- they are cheap now that Chinese stuff is coming in. The aftermarket rotors have more thickness variation than OE (about 20 microns), but still ok, unless you are braking from a very high speed- then could feel some judder; but normal driving ok.

Mr_Shiftright · August 2005

Pagid is good, worked fine on my 300D.

You STILL haven't told us if this vibration occurs while you are braking or while you are accelerating.

pselaphid · August 2005

Vibration, and presumably overheating occurred at full speed, NOT while braking, though I had braked to a stop previously. This was followed, after some miles and disappearance of vibration, by spongy brakes. This is what made the episode so worrisome.

Mr_Shiftright · August 2005

Oh I see. Well then, definitely pull that wheel right away and inspect the pads, the caliper mounting bolts, rotor bolts, etc. I think this is something more than just a hydraulic issue.

brakeengr · August 2005

spongy brakes = air in the system. bleed your brake lines.
I would still check the pads. Feel the rotor- just stick your finger into the wheel (with car stopped!!!) and see if you can feel excessive grooving on the rotor-
If caliper rubber seals are burnt, you may have a piston that's not retracting, and you may need rebuilt caliper. If stuck piston, could explain vibration even when not braking.

mercedes300d · August 2005

Hi, Sorry for posting my message again, but it seems that nobody saw it, maybe some of you can give me some help.
I have a 1992 Mercedes 300D Turbo Diesel which recently started with problems on the transmission. It works fine on D position, but on Reverse it takes about 4 or 5 seconds or even more to start moving, and then the reverse shift enters very smoothly and slowlly. When the car starts moving on rear direction, it makes a strange noise like vibration or jerking, till it finally stops the noise and starts working fine. Other thing is that if I press the acelerator down to increase speed before the reverse shift is completely engaged, the car jumps a little before it starts runing right.
I remember I had some problems before with the transmission of the same car and the problem was a vaccum valve that was in stock, do any of you have had a problem like the one I have?
Thanks for your help.

Mr_Shiftright · August 2005

I'd check the fluid and if it's at the right level I'd do a major service anyway on the transmission; other than that, you'll have to tear it down and investigate I think. Noises inside a transmission are not a good sign, nor is slippage of any kind.

brakeengr · August 2005

My recent transmission shifting problem was solved by cleaning the valves inside the transmission and adjusting shift points. Be sure to take it to someone who knows about MBs; ideally someone who does only MBs.

Mr_Shiftright · August 2005

Well anyone who works on German automatics should be okay. Grinding noise isn't a good sign though as a sticking valve body might not cause something that noticeable.

tijolo · August 2005

what are some tests that I can do to check to see if my '78 300d is in need of a rebuild? Its only got 84k miles but....its burning more oil then I would expect. Constant blue smoke and burning 3.5 quarts in 2,000 miles. Half the 2,000 miles are highway miles but that seems like a lot of oil to me.
The engine seems to be running fine, its usual sluggish self. I have changed all the filters and fluids and ran a couple of rounds of injector cleaner.
Any suggestions would help. thanks

Mr_Shiftright · August 2005

cylinder leakdown test will reveal all.

heypete · August 2005

This is in reference to http://www.craigslist.com/sfc/car/91771703.html

I have emailed the seller for more information, but have yet to hear back from him. Hopefully I can see the car, subject it to my extensive battery of tests (much of it gleaned from reading this thread), test-drive it, ask a ton of questions, and if everything looks good, take it to a trusted Mercedes mechanic I know to do a full inspection on it.

According to the pictures and the (albeit brief) description, the car looks to be in good condition. Seller wants $4,300, which is a bit high. Blue Book private transfer is about $1,200. I'd probably make an initial offer around that, and haggle.

The only potential problem I see from here is mileage: The car has 248k miles on the odometer. Status of service records is unknown, but will be asked about. I'll definitely ask to see them. I will, of course, consult with the mechanic to examine the vehicle before I'd purchase it. I'd like to get (hopefully this isn't unrealistic) at least 150k more miles out of it before having to do major work on it. I'm fairly mechanically adept, but unfamiliar with Mercedes internals...I do, however, know a few people who are rather familiar with them, and who would help me out with any hands-on work I need to do. I'd prefer to do as much work as possible myself to avoid high service costs.

One interesting bonus: the car has been modified to run on vegetable oil, and comes with the filtering/fueling station as part of the purchase price. Depending on the quality of the station, it might be worth an extra thousand dollars, maybe more or less. The fact that the engine is pre-converted to biodiesel is a plus too, as I was hoping to do that eventually.

Assuming I can get the car and station for $2k-$3k, and that it is cosmetically and mechanically sound, does this sound like a good deal? I realize I'm asking for an opinion on a vehicle that you have not yet inspected, and with a fairly small amount of information, and I'll take those givens into account.

Cheers!

brynarose · August 2005

aloha sam! this is a delayed reply to you, but thank you very much for your thorough explanation of transmission variables. i have found a 84 300d that shifts "firmly" and no slippage. (and she's gold and beautiful on a more superficial note). thank you very much for your advice,
bryna

brynarose · August 2005

aloha! i just bought a nice 84 300D with no apparent issues except.....
after driving a couple or less minutes there occurs a whistling/squealing sound ONLY at one certain point on the pedal, the sound reappears also at this same point when decelerating. it does not matter what speed i am going, nor uphill/downhill. i haven't noticed it starting immediately upon driving, so i might venture that it doesn't happen at very low speeds.

i reiterate: the sound is connected to very specific spot when pressing/easing the gas pedal both accelerating/decelerating. beyond that one point there are no funny sounds whatsoever and performance is fantastic

all belts are in good shape. no leakage. no temperature issues.
(i can't check mpg because odomoeter is broken, but it seems to be pretty damn good). i can't inspect the engine while the sound is occuring because it only occurs while driving. (unless you have some suggestions for how to?).

my initial thought was turbocharger issues but i have limited understanding of this, so i don't understand why it would happen relevant to gas pedal and not specific speed nor gear? bearings seem unlikely since there is no sound at higher/lower speeds, increased/decreased acceleration. maybe it's not the TC and there's some linkage in the fuel system that would create such a sound? fuel pump? i just don't get it..... do any of you???

thank you!!!!!!! (by the way, i am very happy to join all you in the ranks of MB diesel fans, this is the best car i've ever driven! it took me awhile to find her but i'm so happy i didn't settle for a subaru! biodiesel coming soon!)

brynarose · August 2005

any tips on replacing the instrument panel light and/or adjustment knob on a 84 300D, depending which one is faulty, without removing the steering wheel etc? i'm just figuring out this car, are there secret back entrances? has anyone ever just pulled out the knob and re-threaded it? i'm sketched out by little plastic breakable things.

thanks!

300d · August 2005

Mr shifty HELP!!!! please

I have a 1985 300D, that and the hazards only work when they are in the mood to. I put on a new combo switch, all new fuses and a new relay. but nothing has changed. Whats next? should i go thru the harness? run a new wire? is their something in the system that i don't know about? or should i move to the front lawn and plant flower in it?

Mr_Shiftright · August 2005

If I recall, I think the entire instrument panel just pries out along the rubber seal. I can't recall how good the access is when you do that. The little bulbs are twisties and they often corrode at the contacts and this is why they stop working. Very typical problem. You can buy all this stuff at the Benz dealer, they stock it.

Mr_Shiftright · August 2005

Why are the hazards such a big deal for you if I may ask?

Anyway, do your directionals all work?

300d · August 2005

um i realy don't care about the hazards. how ever driving with no turn signals it is pretty hazardous. so to answer you question the turn signals do not work. when the ocation pops up were the hazards work the lights will blink at least in the back.
I think i have a blown bulb in the front. but i haven't changed it because im buying knew fender and i want to do every thing at once.

Mr_Shiftright · August 2005

Well all the bulbs have to be good for things to work properly. You might loosen the bottom part of the steering post so you can access the directional signal switch and perhaps that black coupler is loose or you'll see some disconnect in there. You can also take a simple test light and see if there is current to the various sockets in the front and rear bulbs. Also a bad ground at the bulb sockets will cause this, so get in there and clean and jiggle things around.

mercedes300d · August 2005

Thanks for your messages. I think the problem started after driving on a very bad and dusty road. That road really was completly covered with powder, at least 1 foot of dust... I noticed that the problem started after that day, may it be the cause? How can a road full of dust damage the transmission? Thanks again.

Mr_Shiftright · August 2005

I don't think the road conditions are related.

goldcar · August 2005

I have talked to that seller before. They regularly purchase old Mercedes diesels, convert them to vegetable oil then sell them with the fuel station. The car is probably already sold at or very near the price advertised. On the plus side, they do get every car well looked over before the purchase it for the conversion, as they don't want to get stuck with a lemon after investing all the time and money into it.

I ended up buying a cheaper and unconverted '82 300D after I realized my lifestyle just would support another hobby like collecting vegetable oil. Now, if someone were selling vegetable oil ready to pump into my tank for $1 per gallon, I would be all for it.

If you are not planning to "do the vegetable oil thing", then skip that car and get one unconverted.

olympicstar · August 2005

Hi, I am new to the forum. I really enjoy reading the postings as I have managed to apply a lot of the suggestions posted here to keep my 1983 300 D in shape. I bought the car 5 years ago due to nostalgia as it reminded me my childhood trips in taxis with my father in Europe. Then I also realized that is a marvel of engineering.

I am having a similar problem with my turn signals. They do not work all the time. They only way to get them back is if I turn the hazard switch on and of a 2-3 times. Any suggestions?

Regards

Thank you

goldcar · August 2005

I fixed the door locks on my 1983 300D a few months ago (replaced front passenger door lock actuator) and thought I had mastered the vacuum system. Hah! A couple of weeks ago the door locks stopped working again and engine shut-off took 20 seconds. I used my vacuum pump/gauge to determine the interior locking system still worked.

In the engine compartment I found the lines running into the interior (air conditioning and door locks). If I applied vacuum pressure to it I could operate the door locks fine and it held a vacuum. The line to it came out of what I guess to be a one-way valve (white).

I then connected my gauge on that line going back into the main system (leaving the interior sub-system disconnected). Then I disconnected the second line going to the central vacuum connector and plugged it with a gold tee. I re-started the car and pressure shot up to 20-22. I turned the key off, but the car kept running of course as the shut-off valve was part of the second sub-system I disconnected. After pressing the STOP button (darn useful thing), the pressure dropped to 0 over the course of 30 seconds or so. Meanwhile, there was a ticking sound while the pressure dropped.

The hoses looked fine, but there could certainly be a problem with them that I don't see/hear. My main problem is that I don't know how this system should work. I am thinking that maybe it is ok that the pressure drops in the main system, but then there should be a one-way lock sealing off the door lock system. Is there one?

But then, the pressure should be a bit higher or constant to get the fuel shut-off valve to work faster.

Is this a problem with the vacuum pump problem? The brakes feel fine.

HELP! Advice most appreciated. Is this something that is covered in the $100 factory manuals? (If so, I am happy to get them.)

Thanks

heypete · August 2005

Hmm. All right.

I actually did a bit more looking around, and I found a 1992 300D turbodiesel in surprisingly good condition. See the pictures here. No more pictures, as the camera battery was low.

Body was in great condition other than a few mild scuffs on the back bumper (as noted in the last photo). Engine started promptly and ran smoothly. Transmission shifted smoothly between gears at both city and highway speeds. Suspension felt really good.

Interior is in excellent condition, with no visible wear on anything except a small crack on the wood veneer next to the ignition (looks like someone missed the keyhole and poked the wood with the tip of the key). Doesn't look like anyone ever sat in the back seats. No wear on the leather at all, it seems. Very minor wear on the rubber on the pedals, suggesting a minimal amount of stop-and-go driving.

Car has 198k miles, and the seller reports that it's nearly all highway miles. He's the second owner, and has kept the car garaged all of the time it's not moving -- he bought it with the intention of shipping it to Uruguay where he spends several months out of the year, but the taxes and fees for that were too much, so he kept it here and rarely drove it. He only put 3k miles on it since he bought it 4 years ago. Previous owner was a woman, and evidently drove it regularly on the freeway, but very little in the city. Maybe she was a saleswoman or something?

Seller wants $8,500, which is about twice the Edmunds TMV. I may be willing to go a bit above the TMV if my mechanic examines it and determines it's in very good running condition and no major work will need to be done other than regular service for the indefinite future.

I'd be trading in my two-year-old Honda Insight (2003) with 20,400 miles on it for the Benz, and would like to make sure I'd be making a good impression. One of my diesel-savvy friends says that it's not uncommon for Mercedes-Benz turbodiesels to last upwards of 400k miles with proper maintenance. The Insight is a bodywork-hog, requiring expensive bodywork even for minor things like rock impacts. Even with slightly higher maintenance and service costs for the Mercedes, I think I'd save money in the long run.

Any advice?

Cheers!

Mercedes 300D Suggestions

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