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Mercedes 300D Suggestions



  • fintailfintail Posts: 40,958
    The key is maintenance. EVERYTHING has to be up to date, or you will pay for deferred requirements. The cars also need regular fluid changes, and need the same maintenance to retain cosmetic appearance as any other car. It seems many people stretch themselves to buy these things as a second or third owner, so the cars miss out on what they need both inside and outside. You don't want one after that unless you have it inspected and budget for the needs. For any car, get it checked out, and find a good indy mechanic...from my experience, MB dealers don't like dealing with you unless you drive a new S-class.

    For cars to avoid if you want less hassle, I would keep away from W140 cars, earlier W210 cars especially from the east coast, earlier W203 cars, most W220 cars, along with some SLKs and MLs. Those years aren't set in stone, but they kind of go along with the passing of the W124, to the birth of the current models. If I was to get a W211 E-class like you mentioned, I would get a facelift model, or 2005+ AMG. Lots of them were dumped into leases, so they depreciate swiftly.
  • hpmctorquehpmctorque Posts: 4,600
    I wouldn't be interested in any W140 or other S-Class, or ML, but would mainly consider a E or C-Class, in that order. The year would depend on whether it was a replacement for my wife's TL or my E30. For example, a W211 would serve as a replacement for the TL. What year was the W211 facelifted?

    I'd also have some interest in an SLK, as a replacement for my 300ZX.

    I maintain my cars very well, and we average ~19,000 per year for the three of them combined, so I don't need to make any changes. Still, you never know, especially with older cars, when you might have to replace one quickly. For example, a relatively minor accident could total an older car. You usually have advance notice regarding the failure of a major component (engine or transmission), but not always. Also, sometimes several small things fail or don't work right, and together they might equal the cost of repairing a major component, so you decide that its time to trade that car. This is a wordy way of saying that it's good to be prepared. That means having an idea of which car(s) would be suitable replacements for the one(s) you currently drive.
  • fintailfintail Posts: 40,958
    The W211 was facelifted for 07, and the engines were bumped up in size and power, from E320 to E350 and E500 to E550. The CLS is also based on this car, if you want something with less visibility but more visual impact. The W211 is going to be replaced in model year 2010 or 2011.

    I know a couple people with later (04-05) W203 C230 kompressor cars, and they haven't had any real problems, those cars seem to be well sorted. But the earlier ones can be glitchy. I think the current (05+) SLK has been decent too...but if you are tall, you won't like it...I didn't like the one I sat in anyway.

    I don't know if any of these cars will have Japanese reliability when it comes to electronics, and servicing has to be more as well. I think that shocks some people.
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 56,772
    I think we are drifting off topic here. Let's try to stick with the 300D. Thanks!

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  • Hi, I have a 1979 300sd. I posted some time ago about a vacuum problem and am happy to say it is solved. I have recently developed another problem and hope someone can help. My tach has started working intermittedly some days it will work all day fine and others not at all. I am not so concerned about that but what does concern me is that when it is working the car is not as quick on take off and takes forever to get from 45 to 55 and at 55 that seems to be as fast as it will go. However when the tach is not working the car accelerates alot faster and gets to 55 and beyond great. If I am driving with the tach working and it stops working the car accelerates then if it starts back working it is like the car pulls back. My question is is there some kind of govenor or something that would cause this. Any help would be greatly appreciated.
  • Hi does anyone have any suggestions about my problem. Its almost as if the turbo does not work when the tach is working. The only thing I can trace it to is a little thing on the firewall that has a line running from the passenger side of the engine and then has one (a line) running out the other side of it (the thing on the firewall) to the top of the injector pump. I think it has to do with boost pressure but really don't know. It also has something electrical plugged to it that seems to run into the firewall. Could this be the culprit????
  • Went a number of weeks without adding any Redline to my fuel (not carried by local stores anymore). Noticed a pinging coming from the engine on startup...went away after engine was warmed up. Mechanic said add a double dose of Redline (I ordered several gallons online)...engine is now sounding normal. Also noticed that my mpg improved significantly with the double dosing. Question: would double dosing hurt my engine over time (or just my wallet)?
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 56,772
    Maybe what you heard is called "nailing" in the diesel world and yeah, dirty injectors can do that. Was the Redline an injector cleaner or a Cetane booster?

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  • The additive was Redline Diesel Fuel Catalyst....which I believe is both a cetane booster and cleaner. Is that what I should be using regularly?....and would the double dosing hurt my engine over time?
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 56,772
    Don't think so. That's good stuff! You might try BGK-44 as an injector cleaner.

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  • Great! Thanks for your help and support in this forum!
  • ok- here's a strange one. My 300D was (and is) running perfectly. I tried to make it more perfect- here's what I did:
    I was thinking of getting the EGR removal kit, but noticed that my EGR was already disabled (good!). The vacuum line going into the EGR was removed and the EGR opening was closed up by a screw. However, the end of the vacuum line (that originally went into the EGR) was open, so I thought it would be better to plug that up too, so I put in a screw to close it. I also put a couple of golf T's in the black control box since I noticed there were a couple of open ports.
    I take it for a drive, and everything is A-ok (I thought shifting was better- but maybe just an illusion).
    Anyway- I come back, turn off the key and voila! engine does not shut off. Had to shut it off manually. I must have affected something; so of course I remove the screw and the 2 golf T's that I had put in, and the engine still refuses to shut off.
    What could have happened? any ideas? All I did was try to plug up some open vac. lines!! Even after restoring them to the previous status, why does the engine still not shut off?
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 56,772
    That means a vacuum leak somewhere. I bet by increasing the vacuum in the system by plugging a small line you opened up a bigger leak somewhere else. Shifting is also vacuum controlled. Maybe you pulled or yanked something?

    There are these tiny tiny vacuum lines over the valve cover, on the driver's side. If you are working on the engine, these always seem to come loose from their fragile plastic connectors.

    You know where the manual shut off is for the engine, right?

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  • I'll check the vacuum lines on the valve cover- but I was quite careful not to disturb anything else. Shifting is still fine... and yes, I know where the manual shut off is; that's what I used to shut off the engine. Thanks-
    What do you think about removing the EGR valve and blocking off the exhaust and intake using one of those kits?
    Along those lines, any comment on removing the air filter box and replacing it with the direct air intake kit?
  • Problem solved- there was a vacuum line going to the engine that had gotten disconnected from the "Y" branch near the brake booster- connected it back up, and engine turns off normally. I am surprised- the small plastic connector looks very fragile, and barely holds up in the port; for good measure I tied the line with a piece of string to give it support so it doesn't come loose again.
    I also now plugged up the open EGR line with a screw; and shifting- though very good before- is even better now; real smooth and not hard. I can barely feel the shift into 3 and 4.
    Anybody have comments on replacing the standard air box with the "high performance" direct air kit with the K&N filter?
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 56,772
    Yep those are the lines I was thinking of.

    No, I think K&N is a complete waste of money on a diesel--there is no air throttle regulation on a diesel--all you are doing is adding fuel.

    And yes, I tried it on mine and it makes no difference whatsoever.

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  • OK- thanks.
    I have another question though: Even though the vacuum line to the EGR valve is no longer connected, is the exhaust still going into the engine intake thru' the EGR? My thinking here is if any soot/ crud is going into the intake, will it be helpful to remove the EGR and block off both ends- the exhaust as well as the intake where the EGR connected, in order to prevent carbon deposits from going back in? There's a kit on ebay for $30 that does this, and seems simple enough.
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 56,772
    If the vacuum is disconnected, the EGR valve won't open. Unless of course it is stuck open right now. Usually you get EGR action on that car off idle and up to, but not at full throttle. At idle and full throttle, no EGR.

    If it's running okay, I wouldn't mess with it. Your car is emissions-exempt anyway.

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  • Can somebody tell me how to test if the glow plug relay is functioning ok on a '82 300D? The car wouldn't start; checked the battery- put in a new battery. After 2-3 days, won't start again. I suspect one of the things may be the relay not shutting off, and power being drained from the battery even while driving. So I would like to check the relay. Any other ideas?
    I tried to get to the voltage regulator behind the alternator; but just couldn't get to 1 screw to remove it- gave up.
  • Hi I have a 1979 300sd and my heater does'nt work, it used to but for some reason now it will not. The blower works fine and the air changes direction when different settings are pushed, but it only blows out cold air, even on defrost. It is not a/c cold, just cold air. I was wondering if the engine thermostat could be the problem?
  • fezofezo Manahawkin, NJPosts: 10,330
    That's certainly a good first guess. You got a temperature gauge in that? If it barely lifts off the bottom of the gauge it's probably the thermostat stuck open.
    2013 Mazda 5 Grand Touring, 2010 Toyota Prius IV. 2007 Toyota Camry XLE, 2004 Toyota Camry LE, 1999 Mazda Miata
  • I once had this problem on my 300 cd. There is an electrically-operated valve between the battery and the back of the rockerarm cover.You can identify it by its water hose connections. the technician took it apart and either cleaned it or put a kit in it. he said it corrodes with time and does not open to allow hot water to flow through it to heatercore. Good luck, as I believe you can easily solve this problem. Had the technician not shared and explained the process, I would have been puzzled too.
  • Thanks for the information. I am changing the thero. tomorrow and I will check out the valve and see what i can find. The temp on the car does run cold and the temp does not change when you turn on the heat setting. It also takes it a while to warm-up.
  • burdawgburdawg Posts: 1,524
    The servo valve is the part your thinking of. It's a black plastic box with electrical connectors and hoses (vacuum & water) connections to it. On climate control II it controls everything, heat, cool, vent outlets, etc. The buttons on the control panel override it to some extent, but your dead in the water without it. It usually can't be fixed, and is costly to replace.
    It may not be your problem, it's possible something else is. MB has a good manual for the climate control, unless your very familiar with the system you really need it.
  • OK, I changed the thermostat. The one that was in there was actually broken and turned sideways. So It did need the thermo. However it did not fix the heat. I think the problem is the auxiliary pump. If I am correct, this part pumps the water through the servo and into the heater core. The water is getting to the aux pump and no farther. Now I do not have the time to order another one because it is going to be 15 degrees F here tonight. Is there anyway to bypass the pump so I can get heat until I can get the part. Any help is greatly appreciated. :confuse:
  • burdawgburdawg Posts: 1,524
    The auxiliary pump only comes on below certain temperatures (I don't recall what) and doesn't block the flow of hot coolant to the system, it only assists. Quite typically they go out and you don't know it. I doubt if that's the problem, since it would still put out heat even if the pump was bad, just maybe not well in real cold conditions. Remember that these were designed in Germany where cold weather is more of a factor than hot weather. There's a sensor mounted to the servo valve (on the bottom?) that senses the temperature of the coolant and keeps the climate control off until the coolant reaches the operating range, that is possibly your problem, but 9 out of 10 times the problem is the servo valve. Otherwise I would look at the control assembly (the buttons on the control panel), since vacuum leaks can occur there also. Vacuum is real important with this system, and unfortunately there's potential leaks all over the place in a car this old. I had a 1980 280se, and the climate control along with the central locking system were the things that kept me busy on it the most. I can't even guess how many times I had that climate control manual out. The person that bought it from me got a good deal, since it included all of my notes in the margins!
    Sorry if I'm a little fuzzy on some of this, but it's been a long time, and I sold my MB manuals some time ago since mine is long gone.
  • Thanks burdawg for the info. I don't know much about these servos only what I have managed to find online. I did see that there is a heater valve underneath what they call the ornamental grill, which is under the windshield wipers. It looks like it is beside the wiper motor. Now I know that hot water is getting through the Auxiliary water pump(the water line to the pump is warm and the bottom of the pump where the water go through is warm) and the lines to the servo(small hose that goes from the Aux water pump to the servo) seem to be warm as well. So here would be my next question. Is there a valve in the servo itself that allows hot water to get to the heater core or is that valve( the one that opens to allow water to go through heater core) actually under the ornamental grill beside the wiper motor? I hope this isnt to unclear. Please any help would be great.
  • sounds like you are on the right track. hot water is getting to the distribution point, however the piston that allows the water to pass through may be stuck due to 1. corrision, 2. lack of electrical power to the unit, a).no power to unit itself b) no power to the switch that actuates the mechanism it self. I would go to the fuse box first. all fuses are identified and one can tell which fuse belongs to what. if you dont recognize a description, that is probably the name of the part thats causing the pun intended. otherwise raise the hood of the car, have someone get in car ready to operate all controls concerning HVAC , with engine idleing you observe the valve that i originally identified fo you. if you see now ch ange after each adjustment is made then the valve is defective due to one or more of the reasons mentioned above. good luck
  • burdawgburdawg Posts: 1,524
    If it's like my 280 was, and I'm about 99% sure it is, the valve is the bottom of the servo valve assembly. You can take the top off of the servo valve assembly and watch it turn back and forth while it's being operated like benzsilver said. I wouldn't try to take the valve apart. If you turn on the defroster the valve should turn to max heat (and the A/C compressor should be on if it's working), the other control positions may make it turn to lesser heat depending on the conditions. Check the vacuum connectors where they mount to the valve, if the rubber has dried out it may be leaking there.
    I can't stress the need for the factory manual enough.
  • The part you're looking for is the mono valve, a component on these Merc's that fail like they're going out of style.

    You can check the existing valve for function with a multimeter. Infinite resistance and it's pooched. They aren't too too pricey from the dealership, so it would be very benificial to just replace the mono valve and not have to worry about it.
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