First Mercedes (240D), first diesel, advice?

I am a neophyte MB owner, after inheriting my father's 1981 240 D. I have never owned a diesel, much less a Mercedes-Benz, and I wanted to keep this car as part of my father's legacy as opposed to just selling it.

This car was his pride and joy. To say that it has been babied is an understatement. He bought it with 75k miles, it now has 185k on it, but his mechanic was quoted as saying that the engine "is just starting to get broken in.." or something to that effect. The engine is immaculate, no grime, leaks, etc. We have all of the receipts and records of routine maintenance.

It was never driven in the winter (he lived in central NY), and it always had simonize applied religiously. There is not a speck of rust anywhere.

That gives you a little background on it. My question for this group is:

How long should I expect the car to last?

What maintenance items should I be looking for?

Not that I'm looking to sell, but approximate value?

Any general tips on driving a diesel in general, and the 240 D specifically?

What speed should I not exceed? Speedometer only goes to 85.

thanks in advance.

[silverfishk8]

Congrats on your new car! Is it a 4-speed standard? I have always wanted on of those. Here are some answers for you.

If the car was that well taken care of, it should go to at least 300,000 without a rebuild to the engine. If the tranny is a manual, they are said to last forever.

Change the oil regularly, brake fluid once a year or two years, glow plugs if the light blinks, fuel filters if you get hesitation on acceleration, and I think that about covers it.

Value varies depending on location, but around $2500-$3500. Maybe a little more, depending on who you ask.

When driving a diesel, don't be afraid to floor it when you need to accelerate.

I doubt you can get it much above 85MPH.

Good luck and enjoy your new car.

[rickjordan]

Being it that you are in Maine, you will definetly be use the block heater, asuuming it has one. Oil changes are key as are valve adjustments every 15K. As for the glowplugs, using a basic meter and ohming them out will tell you what condition they are in. Anything above 1 ohm I believe, means that plug is on it's way to burn out. Obviously if the reading is infinite, then it's shot. Yes the glowplug should flash to idicate a faulty plug, but I have sen where the glowplug light would not come on and it was due to 2 flat out bad plugs and one reading high ohms.

[jcd]

You have a great car. I purchased 1977 300D from my dad a year ago and I love it.

How about some details on the car or some pic's.

JCD

I have one myself...first, you need to change your oil every 3,000 miles faithfully. If your car is in as nice a condition as you indicate, the answer to "how long will it last?" is .... almost forever.

I'd get a copy of the shop manual by Haynes for the W123 diesels. This SHOULD spell out what maintenance steps you or your mechanic need to take at what interval. I'd also make sure I had the owners manual that came with the car.

To bring you up to speed on Mercedes, I'd suggest joining the Mercedes Benz Club of America, at most for their magazine The Star. As important as the editorial content are the ads for parts and service. A paperback history "Mercedes Benz Buyers Guide" by Frank Barrett is available at all large bookstores. It is most valuable with hints as to what to look for/look out for in cars like yours.

Value is a paradox: you can buy the most perfect W123 car in the country for around $5,000...but you will have an almost perfect and indestructable machine, easy and cheap to keep up, and perhaps the last truly "permanent" car to be built.

There are a lot of Mercedes people in Maine, including one guy who shows up at far-flung events in a '70s sedan which would be ordinary except for its condition. He always drives off with a prize.

BEST of luck.

[P.E.Haiges]

The most important thing is to keep it out of the salt, be it road salt or ocean salt. That is why it is in such great condition because you Dad always did that.

Oil changes not necessary at 3000 miles if you use synthetic oil. Change the oil filter when oil is changed.


Maintenence on a Diesel is minimal. Fuel filters only need be changed when lack of power is noted on a hill and then probably only one of the two is plugged. Replace the primary (inline) filter first and if there is still a loss of power, change the secondary filter. Valve lash should be checked every 25,000 miles and adjusted if necesary. AIr filters are good for 50,000 miles unless driven in dirty conditions. Check oil level in the manual trans and fill with ATF. Check differential oil level and fill with 90 Gear lube.

If engine starts knocking, it is probably a bad injector but this is rare. If that happens, loosen the nuts on the injectors that have the fuel lines going thru them one at a time to find the cylinder that is knocking. Note: fuel will spray out when you do this. Then replace the bad injector or take it to a Diesel shop and have the tip replaced.

P E H

Use the O ring when changing oil filters. It comes with a flat ring also (Bosch) I got my car with the flat ring in place and assumed that was what to use but I leaked lots of oil. I have talked to people in passing that have 240 or 300d's and have the oil changed at the fast lube places with the same problem, the workers there do not know so you'd better tell them.

Is it a 4-speed standard?

Yes. The transmission works very smoothly, although sometimes it hiccups shifting into 2nd. I don't think it's me, because I have driven a standard for years.

Sorry, I don't have any pictures yet. At some point I'll try to get some and post them.

Who should I see to have a valve adjustment done? Do I need to go to a Mercedes dealer, or can a competent mechanic be trusted?

thanks for all the advice, it is very helpful.

[rickjordan]

Avoid at all cost, going to a Jiffy Lube type outfit. First, they will charge you extra because it is considered an "exotic", due to the type of filter it takes. Plus, the amount of oil these engines take. Though I am not too sure how much a 4 cyl diesel takes, but the 617 5 cyl engine takes 2 whole gallons of oil. You're not going to get the $25.95 special at Jiffy Lube with a Mercedes. The main reason to avoid those places is they OVER tighten everything, risking a cracked oil pan. When you buy an OEM oil filter it will come with 2 washers (1 copper, 1 steel) and a large rubber O-ring. The copper washer is the one you want to use for the oil drain plug. The rubber O-ring is for the oil filter housing lid. By OEM I mean MANN, Hengst, and Knecht. You can buy these from "Fastlane" at the top of the screen.

[thebern]

my 82 240D needs about 6.7 qts. when I change the oil and filter.
Get your filters at 'Fast lane', buy a quantity ,5 or 6 at a time, they cost less and are better than Purolators-avoid NAPA filters for this car!

Originally posted by rugger
Who should I see to have a valve adjustment done? Do I need to go to a Mercedes dealer, or can a competent mechanic be trusted?

For valve adjustment, it's best to go to someone familiar with Mercedes--a dealer or an independent shop. I've found that it's almost always an older mechanic who can do it best (MB's have had hydraulic lifters since 1985--no adjusting). Most non-MB mechanics have never done a valve adjustment (at least not in the last 15 years). Absolute best way is to learn to do it yourself, of course.

[mikemover]

Congrats on your new ride! Sounds like it's been well taken care of, so it should last for MANY more years, if you continue the good maintenance habits.

Most everything has already been covered...I'd stick with the 3,000 mile oil/filter changes, even with synthetic...It's a worthwhile investment, and will ensure a very long lifespan for your engine.

I also change the fuel filters at every oil change...they're cheap, and it can't hurt...sometimes you'd be surprised at how dirty some of the diesel fuel you'll get is! I change the little clear pre-filter even more often, if it looks black or gunked up in any way.

Also, don't be slack about having the valve adjustments done every 15,000. It will cause hard starting and excess wear if you let it get too far out. Have the timing chain stretch checked at every 2nd or 3rd valve adjustment...MB diesels have very close tolerances, and if the timing chain were to break, valves would hit pistons, and that's not pretty. I get my valve adjustments done by an independent shop not far from my home, and it's less than $100.

Also, do as much highway driving as you can...city driving tends to gunk up the engine after a while.

You may be approaching the mileage point where you'll need to have some suspension work done, if your father did not have it done already...sounds like he maintained it very well, so he may have. After 150-200,000 miles, you most likely will have some very worn and dried out bushings, ball joints, shocks, etc. Your handling will be amazingly improved by having the front suspension refreshed. Also your tires will live much longer. As I said before, it may have already been done. Just popped into my head, since I'm about to have it done to my 79 300SD, and at 245,000 miles, it is LONG overdue.

Enjoy it!
Mike

[P.E.Haiges]

Its ridiculous to change fuel filters when changing oil. If you get clean fuel the filters will last for years. I you get a dirty tank of fuel, even new filters will plug up. New filters do not filter any better or make the car run any better than old filters if the old ones are less than 90% restricted.
I don't change fuel fliters until I notice a loss of power on hills or accelerating hard. Then I remove them and actually clean them and use them again.

I wish mikemover would give me his old filters so I would never have to buy any.

P E H

[mikemover]

hahaha...Hey, I love my car and plan to keep it until the damn wheels fall off, so I figure it's pretty cheap insurance. I've seen some NASTY stuff in my fuel filters from time to time...I don't want that crap clogging up my injectors. If I was going to sweat every nickel and dime I spend on my car, I wouldn't drive a Mercedes!

Mike

Just to note that "research" done by "my guys" who exclusively work on all model Mercedes shows that synthetic oils can cause problems, especially in older cars. One big problem is that seals and gaskets which had been perfectly fine with dead dinosaur began to deteriorate after a short while with synth. So...back to real oil, even in their own cars...and for diesels, the 3k change interval is really important if you want longevity.