My friend and I were messing around with the 240D this afternoon. I had replaced the valve cover gasket a couple of days ago to answer to a bad leaking problem there, hoping that this was the answer to the high oil consumption. It did not. Anyway, I had it running at his place to see what the exhaust looked like. Where the car was sitting, there was no breeze at all. Well, unfortunately for me, the car is making for one hell of a mosquito smoker even with no load on it.

I'm definitely looking at a teardown at this point. I inadvertently trashed a VW diesel in an attempt to overhaul it, and am subsequently VERY nervous about opening this one up. There isn't any way that I would be able to afford the cost of the not so local MB dealer to rebuild it either, so I'm not going to have much choice. So, just how hard are these to rebuild?

Well, I wouldn't say it's impossible, but if you've never done a tear down successfully, you might want to at least have the assistance of someone who can.

You need to consider some things first:

Do you have the right tools (ALL of the tools)?
Do you have a place to work on the vehicle for potentially longer than you expected (waiting for parts, etc.)?
Will you be terribly upset if the same thing happens again (botched rebuild) to this car?
Do you know what you did wrong last time and are you any better at this sort of thing than before?

If you still think you can do it, you need to run some numbers and determine just how much you think you can save by doing this yourself. Parts for these motors, as you know, are often expensive. The little stuff will sometimes add up and kill you. What you save on labor may not be worth the hassle if there's an economial choice. I can't imagine there's nobody near you (forget about the dealer) who can do a rebuild at a reasonable cost. Go to the nearest major city and check the phone book (Cities have more rich people than do the boondocks, these rich people have Mercedes Benzes, the smart ones sometimes go to cheaper and/or better places besides the dealer to have work done...you get the picture)

It may not have to be a total rebuild, either. Although that would be best, you can only do what your budget allows. Is the top end totally shot? Can the cam and maybe some of the valves be saved? Do you insist on new parts, or will rebuilds be okay?

Have you priced many rebuilds? There are varying grades of quality/performance/price/availability.

Finally, you could take your chances with a used motor. You may want to scour local or online salvage yards looking for a recent wreck that has your car's motor with some life still left in it.

In short, I'd just say consider everything, as bottom-end engine work is a little more of a task than most of us are prepared to undertake.

Hope this helps
Gil

I have found used diesel engines at auto wreckers. They are plentiful. I live in Canada, where you get less bang for the buck than in the States, and a good used 5 cyl. non-turbo engine is $1800 Canadian. Our dollar is about 61 cents US, so I suspect that you should therefore be able to find a good used engine for a bit over a grand to $1200.00.
Just a thought.

You can buy a rebuilt long block '80 240D engine for $2790 plus $500 core (get all back if your engine can be rebuilt) plus $175 S&H from remanufacture.com. This engine will have a 12 mon./12,000 warranty. A long block will have the complete head and block assembled, but not the valve cover, injection pump (may get this, you'll have to call them), alternator, power steering pump, starter, manifolds, etc, etc.

Another place to try is Engines Direct at 800-998-2100 in L.A. Engines Direct would sell me a 77-79 300D complete engine (including injection pump) for $2,990 with no core charge (you do not have to ship them your old engine), plus $75 S&H. These engines are made in Holland and come with a 12 mon./12,000 mile warranty. You'll need to call about your engine for price and availability.

I have no experience with either of these companies, so I cannot tell you how good their engines are. Perhaps another member can tell you about them.

Adist (adsitco.com) will sell you a used '80 240D engine for $1250 plus $500 core, plus S&H, and a 30-day warranty with no refund only exchange for another engine. Adsit sells rebuilt 240D engines for $2995 plus the same core and S&H cost as a used engine with a 12 mon./no mileage given warranty and no refunds if the engine is defective. They also have short blocks (no head), but do not give prices - so you'll have to call if this will fix your problem. Adsit has been in business for many years and some members have commented that they are reputable.

Others have made some very usefull comments. I will add that an engine swap is a lot easier than rebuilding an engine if you do not have the technical expertise, tools, information, help, etc. If you get a good manual (Haynes for example) then an engine swap is doable with some hand tools, engine hoist, perhaps an engine stand (you can put it on the floor with blocks to support the engine if you have to swap parts from your old engine), some help, and a bit of patience to do the job right and not rush through it.

On the other hand, your engine may have something as simple as a broken piston ring causing the smoke and can be fixed for a reasonable amount. If the engine is worn out, well . . . You will not know know what condition the engine is in until the engine is checked out. A compression test and perhaps a pressure test will tell a lot about the engine's condition. Both tests can be done for a reasonable amount of money.

Hope this helps.
Good Luck!
Tom

__________________
America: Land of the Free!

1977 300D: 300,000+ miles

American Honda: Factory Trained Technician & Honor Grad.
Formerly:
Shop Foreman;
Technical Advisor to Am. Honda;
Supervisor of Maintenance largest tree care co. in US for offices in Tex.

How many miles are on the engine that is in need of rebuilding?

I need to give everyone the whole story on this engine. I've neglected this (my bad). The previous owner rebuilt this engine 10K miles ago in an effort to correct this problem. The engine had 180K on it at the time. He was not successful in fixing the problem. He was very upfront with me on the oil consumption issue. He also made mention that the rings that he bought looked physically different than what came off. Myself, I would have looked into this before putting them in anyway . I don't know why he didn't. Based on this, I don't think a total overhaul should be necessary. My theory is this:

He either did not hone the cylinder bores to the proper spec, the rings are the wrong ones for this year of car, or he broke one during reassembly and didn't know it.

The car starts almost immediately and runs smoothly even with temps in the low teens. It DOES develop a lope once warmed up at idle. I was suspecting a sticky injector. Fuel mileage is on par with what others have posted here. Performance is excellent. It just has a whale of an appetite for oil (1 qt/300mi).

As for downtime. I have three other vehicles, so I am not in a position where this has to be done now and quickly. I would prefer not to go the used engine route as I want this to be a "collector" car eventually. I also want this to be able to be relied upon for road trips. I just don't want to have another donation to the local high school.

sounds like one or more bad oil rings ,maybe you could get but just replaceing them.....
William Rogers.....

Like William suggested, why not just rering the motor? I know when my Jetta Diesel was getting tired, the local VW mechanic suggested new rings & a cyl. honing. This could be done with the engine in the car. Pending the shape of the cylinder walls couldn't the same be done on a MB Diesel?

Aivars

forget about it.if you could not rebiuld a volkswagen you cannott do the mercedes.Buy a complete used engine.Some wreaking yards will install it.Good luck .

I've done much deliberating on what needs to be done about the car. I will be attempting to fix the car myself after I return from a trip next month. Before I do open this car up, I will have it checked by a diesel mechanic to be absolutely sure what I need to do to get it working right. I have both MB shop manuals and Haynes manuals to study on the overhaul procedure. Many thanx for the input. I'll be keeping the group posted on what I find when I open it up.

Having just gone through this I would suggest finding a good, reputable machine shop that does diesels. Tear it down to where you feel comfortable that you can put everything back together and take it to them, explain the problem and see what they tell you. If there is a problem with the cross hatching it will be obvious when you pull the head. A couple thoughts on high oil consumption on a newly rebuilt engine are a) improper cross hatching b) improper break in driving style. The improper break in would not allow the rings to "seat" like they should. The Haynes manual is pretty specific as to how to drive during the "break-in" miles.

__________________
Jim

Before you take the engine apart, check the hose from the vacuum pump to the intake manifold for oil.

If there is oil in there, the problem is a bad vacuum pump diaphram, not rings. Much cheaper to fix, too!

A bad diaphram will pump about a quart of oil in 100 miles or so down the intake. Smokes like crazy (blue, not black), starts hard from all the oil in the engine, and will run the crankcase dry pronto. You will also have a hard brake pedal.

The diaphram on a 240 can be changed without taking the vacuum pump off! Even taking the pump off isn't a big deal, unlike a W115.114 300D!

Also, check for blowby by loosening the oil filler cap at idle -- if it chuffs like a steam locomotive, you have ring problems. If not, for sure I'd check the vacuum pump!

Proper breaking in for an MB diesel will require running at high load/low speed (almost lugging the engine) on some steep hills if possible. You need to work them pretty hard to get the rings to seat. Don't use synthetic oil for assembly, use dino until the rings seat and oil consumption goes down, or they won't seat at all!

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

I had a 190D that burned a huge amount of oil. I put in new rings with out any improvement in oil consumption. I finally found out that the head was cracked and the oil going to lubricate the cam and valves was leaking thru the crack into the combustion chamber of #1 cylinder. A different head solved the problem.

P E H

Thanx for the suggestion. The vacuum pump has already been checked. Tube is clean, and no problems with the brakes. I replaced the valve cover gasket (leaking bad), oil drain plug (damaged & leaking), lower oil pan gasket (unsure of leak or not, but gasket was "wet"). These resulted in no change, and in fact, the new gasket is already having oil forced out the back sealing area on the head . I can feel the individual cylinders "fire", yet the amount *is* less than the Datsun, which had a similar appetite for oil. Other notes have been oil being forced around the crankcase vent and oil fill cap from inside.

Before I do tear into it, I am going to perform compression and leakdown tests. I simply need to sideline this car for the next few weeks to prepare the Samurai and myself for a 3600 mile round trip into the northern Rocky Mountains.

Keep us posted on the results of this. Spending $3000 on this car will get you very upside down in it, and should not be donw lightly. I would exhaust all other potential avenues prior to buying any parts/engines. A top end is less than a new engine, and a re-ring is less too. Check it out carefully...

__________________
John Shellenberg
1998 C230 "Black Betty" 240K

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