Mike,

As GM demonstrated with their Diesel car experiments conducted by the public, there is nothing about running on Diesel fuel that makes the engine last longer. However, if you examine the markets where Diesels dominate, such as heavy trucking, train locomotives, marine transportation, etc., you see singificant numbers of machines that last, in very severe service, many hundreds of thousands of miles. While this is not an unachievable goal for gas engines, as there are notable examples with the ability to last for similar, unusually high numbers of hours of use, it is rare to combine this feature with exceptional economy.

Heavy trucking use pits much more highly stressed, using your perspective on stressing an engine, engines against much more rigorous use than any 240D or 300D will see. The horsepower per pound ratio for trucks and their usage factors are much higher than a 240D or the typical car.

Diesels designed for these industrial markets are engineered to have long lives, more so than the typical gasoline automobile engine. Mercedes-Benz brought the Diesel to the automotive industry and practically owned the taxi cab market around the world, except the US and UK. So, they were optimized for economy and longevity. They missed out on a few things people like about gas engines though, like low weight, high output, etc.

There is nothing that says gasoline engines could not follow the same path, they just have not for various reasons. The most probable being the added cost for something a lot of people would not keep long enough to see the economic payback on, so it has no value. Hope this helps, Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

That's still kind of a micro-cosm, though.

So both gasoline-powered cars gave you 10,000 miles of service and then expired? Interesting...

My 177K mile Volvo was purchased in 2000 with 143,000 miles. No major repairs have been performed on the car, just routine maintenance and minor repairs.

The 204K miles 380SE in our family was purchased in early 1999 with 141K miles on it. It ran until last June, when its timing chain slipped a few links and valves and pistons got to know each other. $2500 later, the car ran again.

The 940SE has 212K miles on the original engine and transmission (similar units to the 740T. Same engine, different turbo).

Of course, this is another microcosm, but we've generally had very good experiences with our gas-powered cars. While these are nowhere near the insane mileages racked up by 220Ds and the like, these cars run very well with regular maintenance.

Before the 380SE, the last major engine failure than happened to any cars that my parents owned was with a '69 VW Bus that my dad had in the mid Seventies. Air-cooled VW engines aren't that durable.

Would your view about diesels have changed if you had owned reliable gas-powered cars like my parents and I have had the pleasure to own? It sounds like your lousy experiences with spark-ignited engines turned you permanantly against them.

-Sam

Sorry, but the facts disagree with you. Because diesels are built to more exacting standards, and mechanically stronger, they DO last longer...Much longer. It's not at all uncommon to see diesel engines in trucks of all kinds, and cars (except early GM) last for 300,000...600,000...900,000 miles and more, before being rebuilt. Although some gas engines reach those numbers, it's highly unusual.

And per-mile operating costs are lower overall...Diesels make more power-per-unit of fuel than a comperably-sized gas engine, and there are no "tune-ups", per se...No spark plugs, no points, no spark timing, no spark plug wires, less emissions equipment, etc...

I love a big, fast gas-powered car too...But overall diesels DO last much longer, and cost less over the life of the vehicle. There's a reason almost all big-rig trucks, public busses, tow trucks, delivery trucks, dump trucks, construction equipment, generators, etc. use diesel engines. Durability and reliability and economy.

Mike

__________________
_____
1979 300 SD
350,000 miles
_____
1982 300D-gone---sold to a buddy
_____
1985 300TD
270,000 miles
_____
1994 E320
not my favorite, but the wife wanted it

www.myspace.com/mikemover
www.myspace.com/openskystudio
www.myspace.com/speedxband
www.myspace.com/openskyseparators
www.myspace.com/doubledrivemusic

Jim,
Thanks for your response. So would you agree that an MB diesel engine has no advantage over a similar (same era) gas engine?

I really like diesel engines, and would really like to know if there are any real reasons why an MB gas engine cannot last as long as a diesel.

Mike

Actually, no. The first one didn't even last 1,000 miles (blew a piston). The second gave me 10,000 miles before I decided that it was a money pit that wasn't going to close up anytime soon, and that I couldn't rely on it. Both vehicles had numerous problems that I was continuously dealing with, and I was getting tired of it very quickly. BTW, I got 2 months out of the first one, and 9 months out of the second, and I'm relatively easy on vehicles. I got a year and a half out of the Scout (1980 Scout II with a Nissan turbo diesel), without needing to do anything other than routine maintenance (the cracked piston was the result of a modification that I was unaware of, that allowed the engine to overboost and overfuel; even still, it drove fine, but the blow-by smoke {no PCV/CDR valve} was so bad that I got pulled over twice, and the body was so badly rusted-out that it wasn't worth it to rebuild the engine). I got another year and a half out of the van ('84 E-350 with the same 6.9l Navistar diesel that I have in my truck), and it was in perfect running condition when I sold it (I only sold it because I needed a vehicle that got better fuel mileage; I replaced it with the 300D I have now). Other than routine maintenance, all I needed to replace on the van was the starter and the battery cables. I will admit that I've had some problems with the truck (injector pump, starter, batteries, rubber components {it was a desert truck that had sat for a long time), etc), but I have personal reasons for not wanting to get rid of it. The 300D, I have yet to do anything engine-related other than routine maintenance and a battery replacement; I have had problems with the car, but they've all been suspension-related, other than the axleshafts.

In all honesty, no. My bad experience with gas engines just re-inforced my opinion about diesels. I will admit that, had my experience been better, I'd have a more optimistic view on gas engines, but I've been in favor of diesel power for as long as I can remember (since I was a little kid, even, although at that age I just liked the sound and the smell). I've been working with them (mainly in a marine environment) for a big chunk of my life (considerably longer than I've been driving), and I've seen firsthand how they're built with longevity in mind. I also like the fact that there are fewer things to go wrong (yes, the fuel system's more complicated, but it's not that much more compplicated than a carbureted gas engine, and IMHO the complete lack of an ignition system more than makes up for it) and that, in most cases, it's harder for something to slip per se (except for the camshaft in the Benz, and for basic accessories i.e. alternators and power steering pumps, everything's gear-driven). I like not needing a timing light or a running engine to set the timing, and also like not changing out spark plugs on a regular basis (yes, I know that glow plugs need to be changed out, but not nearly as often). I also like that they are more mechanically efficient; better use of the fuel that's delivered. Faster acceleration's certainly nice, but they're not nearly as important to me as longevity. Besides, if you want, you can get good acceleration power out of a diesel; I know of a guy with a Dodge diesel who can outrun a stock Corvette.

I'm impresed with the lifespan that you've gotten out of your gassers (although I would consider the valve-piston meet a serious problem ), but I think that that's more of an exception than the rule. European gas engines may be different, but I wouldn't trust any American-made gas engine past 100,000 miles. EVERY gas engine I've seen (mainly American, I'll admit) has started developing serious internal problems above the 100,000 mark (compression, valves, burning oil, etc). American-made diesels, on the other hand...well, there was a guy on eBay a few months back that had a Dodge Cummins diesel that he was selling that had over 1 million miles on it, and no major problems throughout its life. At least for that engine, that's not all that uncommon. The engine that's in my truck has a standard "lifespan" of about 300,000 miles before needing a head job or a rebuild (I actually want to replace the 6.9l with a Cummins B-series when the 6.9l goes out). Again, that number isn't absolute; I've heard of people with 6.9l's get over 500,000 miles out of them. OTOH, I have yet to hear of any gas engine with over 300,000 miles on them, and just a small handful (such as yours) with over 200,000 miles on them.

The GM 350 diesel was a scrap heap, but IMHO this is due mainly to the fact that they used a lot of parts off a 350 gas engine in order to get it on the market quickly, and said parts, along with the other parts that GM designed in a hurry for the same reason, couldn't stand the strain. This was coupled with GM techs that didn't know squat about diesels (has anything changed? ). This is from the same group who chose to put aluminum cylinder heads on a new diesel design (yes, I know that MB did this as well, which is why I'm not driving an OM603).

If you're interested, the "Why are diesels better" link in my signature links to a paper that I wrote for a class a few years ago, outlining the advantages of diesels over gas engines. I will admit that there are a few "bulletproof" gas engines out there (the old Ford FE blocks and the old IH gas engines), but those also get horrible fuel mileage (in the 5 to 7 mpg range).

Just my $.02...keep on truckin'

__________________
2001 VW Jetta TDI, 5 speed, daily driver
1991 Ford F-350, work in progress
1984 Ford F-250 4x4, 6.9l turbo diesel, 5 speed manual
Previous oilburners: 1980 IH Scout, 1984 E-350, 1985 M-B 300D, 1979 M-B 300SD, 1983 M-B 300D
Spark-free since 1999

Thank you Mike, couldn't have said it better myself

Mike,
I realize diesel engines are used in trucks, buses etc...This is to keep fuel consumption down, and im sure having the low end torque makes the diesel a much better choice in a dump truck. This however, does not convince me that diesel engines last longer. You say they are built more robustly, but as I mentioned before, diesels have double the compression ratio, so they NEED to be built to withstand their own inherant stresses.

As for operating costs, the days of diesel simplicity are over. EGR valves, trap oxidizors, turbos, glow plugs, vaccume pumps...there is plenty to go wrong with a diesel. And that is just for the 80's diesels. A 211 diesel car will have everything controlled electronically, just like its gas powered cousins. The new generation diesels are not simple engines.

So as far as I can tell, the only advantage to the diesel is the MPG. And the smell.

Please don't get me wrong, I like diesel engines (see my car list), I just find this an interesting debate. Mike

Mike,

There was a time when I was sure an MB gas engine was inferior in terms of how long it would last relative to a Diesel engine. I am not sure of that anymore. I drove my 1986 190E 2.3-16 very hard for 200,000 miles. Granted, I took good care of it for the most part, but I never expected it to still be running strong today, in my son's hands. I have had the head off to be rebuilt at about 205,000 miles due to a burned exhaust valve resulting from a missing a valve adjustment. But other than that the inside of the engine looked like new and it runs like new today.

So, Diesel parts are heavier and stronger, but they have to be to survive. Gas engine parts can be designed and built with the same engineering standards, and in some cases it seems they are. In other cases, like the new aluminum blocks used by MB on the gas cars, I get a little concerned about really long life as well as rebuildability. Not something that will be rebuilt by a regular shop.

In the end, however, the higher speeds of the gas engine will wear things like the valve seals and guides faster, so the head will come off on a gas car sooner, but that should be viewed almost like routine maintenance if you keep your car for several hundred thousand miles.

Good luck, Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

While reading this thread I was smiling most of the time. The Oldsmobile diesel was unique and there are those who think they are the greatest - still. Stop by this location to read a little about their history and problems:
http://members.tripod.com/~A350Diesel/menu.html

I am relatively new to the diesel crowd - I shopped for a diesel and considered the Hummer H1 (even with 150K miles they still sell for $45 - 60K!), an early Toyota Landcruiser, and a host of other forgotten types that were propelled by diesel power plants.

Finally the light went on ---> *MERCEDES* and I realized that an MBZ diesel would be hard to beat. My 95 is without a doubt not only a well engineered vehicle but also and most importantly a great ride!

I live in Texas and as such the cost of gas is relatively cheap most of the year. Diesel runs a little less than regular - until now. It has skyrocketed to Supreme and in some cases has even climbed higher. I still figured my 3.0L diesel gets 33% better mileage than my Jeep GC 4.0L so diesel would have to climb to $2.30 to begin to be a bad investment. I think given the prevailing winds of uncertainty we are being gouged at present - you get 40% more diesel from a barrel of oil and it takes less to crack it!!! So they are charging more and letting the trucking and airlines pass the costs to the consumer - too bad we drivers can't do the same.

I noted some like the smell of diesel fumes! They are not offensive and remind me of my childhood rides on the train and later trips by jet! But this is NOT why I bought a diesel. I like the idea of a well engineered motor with a long life.

Bottom line - I used to own a Corvette and I posted that I have given up the adrenalin rush of a 350 5.0L V8 gas for the pur-r-r-r-r of the 3.0L diesel. The MBZ is so well engineered and such a blast to drive with the top down (read that "sunroof open") that I don't miss the Vette at all - although I don't get the stares I did at one time - but the cops don't eyeball me as much either now!!

I had never considered a MBZ because I knew they were $$$ new. But I didn't realize that most first owners get the maintenance done and usually have more than one car - this means a second buyer/owner can get a like-new car for 1/2 the price or less if it is 5+ years old!

Last thought - my 91 Jeep 4.0L I6 gas is great and has 166K miles now with no sign of oil usage or power loss. I use Mobil 1 in all my cars - diesel included. I think if you pamper your ride, get the maintenance done - treat it with respect - it will last a long time. I have been told that the Jeep dealers see the gas 4.0L engines routinely at 200K with no major work required so you draw your own conlusions about gas vs diesel engine life.

My two cents...no charge
Mike

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A typical experience most people in the USA would have with a diesel car is one of the W123 or W126 Mercedes of the late 70s to early 80s, even into the W124 in 1987 and the early 90s.

All these engines have the injector return rubber hose that goes bad within two or three years and starts leaking.

Thus the car smells like diesel fuel when you walk by it and even when you are in it.

The typical American does no maintenance on their car until it stops running. So, it reeks of diesel. Plus they don't adjust the valves (who would know to do that?) or change the glow plugs, so the diesels appear to be hard starting.

Women seem to hate the smell of diesel the most.

In many families Momma has veto power on the car purchase.



I would not have been attracted to a diesel except I happened to need a compact tractor for grounds maintenance. The cheapest thing to get for that is a gray market Japanese diesel tractor. Yanmar is a great choice, and many people do not know that a lot of the John Deere compact tractors are either totally built under contract from Yanmar or their engines are Yanmar.

So, I was extremely impressed with how the Yanmar tractor ran. It can go full out all day for just a few gallons of diesel - less fuel consumption than my gasolene riding lawnmower!

This attracted me to the Mercedes diesel because of its reputation for longevity, and from the tractor I became aware of just how efficient are the diesels on fuel consumption.

Ken300D

I may be off the mark on this, but there is a reason for the idea that diesels last longer than gassers. It's because of the effects of the fuel on cylinder lubrication. In carburated gassers, when the ignition is turned off, gasoline still runs into the cylinders, washing the oil off the walls and over the years causing wear. Diesels never had this problem because they shut off by stopping the fuel supply. Fuel injection in a gasser resolves this problem to a large degree making current gassers almost equivalent to diesels.

If this hypothesis is correct, diesels will last longer than carburated gassers.

Comments?

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

There are many Gasoline engines that can go 300,000 miles easily. All the Audi's I had, had over 200,000 miles on them when I sold them, and the engines themselves gave me no problems. I know a mechanic who has had several Audi's with over 300,000 miles, with no major engine work. I also know there are many MB gassers out there with over 300,000 and no major engine work. My Blazer had over 200,000 miles on it before the engine finally died, and it had no major work done to it.

The miles we get are great, but what I like is no tune ups. Haven't has to replace a plug wire or rotor cap yet in either of my MB diesels yet.

Glow plugs need to be replaced FAR less often than spark plugs, and even if they do go bad, once the engine is strarted, they have no effect on how it runs...the same is NOT true of spark plugs. Vacuum pumps last AT LEAST as long as the electric fuel pumps on gas engines--and are fairly easy to rebuild or replace when the time comes. Trap oxidizers were a bad idea...that's why MB recalled them and removed them for free. Turbo problems on diesels, particularly Mercedes diesels, are almost unheard of. Diesel fuel itself is basically a lightweight oil, so it has much better lubricating properties than gasoline. Also, as someone pointed out above, diesels are shut off by cutting off the fuel supply, so you have less fuel draining past the rings...but the fuel that does get past them lubricates better than gas would. Diesels tend to generate less heat than gas engines.

I don't mean to turn this into a debate over which is better...It's apples and oranges...But the numbers don't lie. With very few exceptions, diesel engines of all kinds, ESPECIALLY Mercedes (except the notorious 350), far outlast comparable gas engines. Diesel engines are used in trucks for the fuel mileage and torque like you say, but they are ALSO used for ease of maintenance, lower operating costs, and longevity! Believe me, if they were more expensive and shorter-lived than gassers, trucking companies, farmers, commercial construction contractors, and the military would switch to something else QUICKLY!

Ask any truck driver, ask any bus driver, ask any farmer, ask any marine mechanic, ask any military mechanic, ask any heavy-equipment operator, do a search on the internet, pick up an automotive magazine, ask any Mercedes mechanic, ask ANY mechanic....they will all tell you that, love 'em or hate 'em...they last longer.

Mike

__________________
_____
1979 300 SD
350,000 miles
_____
1982 300D-gone---sold to a buddy
_____
1985 300TD
270,000 miles
_____
1994 E320
not my favorite, but the wife wanted it

www.myspace.com/mikemover
www.myspace.com/openskystudio
www.myspace.com/speedxband
www.myspace.com/openskyseparators
www.myspace.com/doubledrivemusic

mikemover,

I agree with your conclusion, but I thought the other Mike was questioning whether or not gas cars can be made to last as long. Diesels last as long as they do because, as a class of machines, they were designed and built to be tools to make money with, which is not necessarily the design goal for most gas engined cars. The other aspects of Diesels, like the increases noise, vibration and odor/smoke make them less appealing to the typical consumer, so they have not been developed for that market. For most of us, that would seem to be a blessing as we apparently favor the industrial ruggedness and economy of operation over those other gas engine attributes.

Mercedes Diesels were developed for the taxi fleets around the world, and come from the same roots as the other industrial Diesels you cite as examples of how long lived they are. I think gasoline engines could be made equally robust, but due to their lower efficiency they are not the engine of choice for industrial applications. And the average consumer of gas engined automobiles is not interested in paying a premium for long life if all he is going to do is trade it in after two or three years of relatively light use. So they are generally not designed to the same standards for longevity and reliability.

There are some gas engines that, in the cars they come in, can do very well with the same rigorous care we give our Diesels. A few have noted examples. As far as the owners are concerned, these engines also provide superior life. Which is fine. The overall set of compromises embodied in these examples, however, is not the same as the set involved with a Diesel. They typically get poorer fuel economy and the cost of ownership over a decade or longer is not even close.

Every one of my old cars died or is dying from body rot after nearly twenty years, not engine failure. This is the same for gas powered and Diesel powered models by Mercedes. I can't say the same for other makes of cars I have owned - some have begun to fall apart and rust within 5 years. Anyway, the point is the intended use of the cars strongly influences the engineering goals, and Diesels are typically developed for a different market than gas engines. Hope this helps clarify my previous notes. Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)