I am 64 and saw my first Diesel back in 58. It was a Detroit 6-71 on my Uncle's commerical fishing boat. Later thru the late 50's thru the middle 60's I was around other commerical fishing boats Diesels, CAT,Cummings, Buda, Murphy, Perkins,Ford (English built) and others.

Then in 1985 I bought my first Diesel, a new Isuzu P'up with a C223 Diesel. I still have this pickup and it has over 520,000 miles, and I can go start it up right now and drive off.

In 2006, I got my first and only MB Diesel, a 1981 240D. This car I use daily to and from work.

The common threat thru all this is the fact that all of these Diesels, are:
inline
cast iron head and block
mechanical fuel injection
no computer controlled engine management systems

It is my opinion these old time Diesels are superior to the new generation of Diesels and will last longer wtih less repairs.

Just wondering if my thinking is different that those of of this site.

Bob
240D

Older diesels are certainly simpler and have fewer things to break, and they are easier to DIY. Later models tend to be more fuel-efficient, produce fewer emissions of the type currently called "bad," and are quieter, smoother, and more powerful. New cars in general are more expensive than old ones, with repairs to the old car being an unknown risk. Many times people on this forum have repeated the mantra "there's no such thing as a cheap Mercedes." Whether that makes either new or old "better" is in the eye of the beholder.

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"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

I feel the perception that modern computer controlled diesels are "weak" or "unreliable" is unwarranted. True, some of the latest crop of cars have had some problems (2004+ VW engines having camshaft wear problems, the new common rail motors have problems with the high pressure fuel pump, IMO related to the poor lubricity of US spec diesel fuel)

Consider the engines that were available here in passenger cars around the year 2000. You had the VW 1.9L TDI ALH 4 cylinder and the Mercedes 3.0 606 6 cylinder. Both motors are known for their power, smooth running, and longevity. Both motors use computer controls to replace springs and flyweights in the injection pump for better running and fewer emissions. This was a period in time where the technology was ahead of the emissions requirements placed on automakers.

Let's consider the 1996 VW TDI motor for a moment (I happen to know a lot about this motor and its management system, I'm sure others here could comment on the control system of the EDC 606 motors that came out in 96). The rotary injection pump used on that engine is very, very similar to the old mechanical injection pump used on the previous indirect injection motors going back to the 70s. But it is actually much simpler. The spring governors and pressure capsule used for fuel enrichment under boost are replaced by one servo motor with a feedback sensor. A simple frequency valve controls the timing advance mechanism, something which was operated by case pressure alone before. The computer running the show is not very advanced by modern standards... there are only 4 fueling "maps", or different sets of data the computer uses to decide how much to move the quantity adjuster. I bet all my babbling here uses more bytes of information then those fuel control maps. Yet this "simple" system is able to give excellent control of the car, and give precise control of both fuel quantity and injection timing.

And it simply does not break. Of all the years I've spent keeping my ear to the ground on the VW forums I rarely hear of a failure of the engine management system. I've heard of one case where the electronic go pedal sensor wore out (and unlike toyota VW built in a fail safe so the motor simply faults to 1200 rpm), and one or two cases of the computer itself going bad. Not too different from the old mechanical systems, I've read of some here having to replace an injection pump... an uncommon occurrence but it does happen.

Electronic controls make the car easier to service. With the proper equipment you can get real time data from the computer to make accurate diagnosis. Can you see what the actual start of injection timing is on your 240D while driving? Or how balanced the injector's pop pressures are? How about what temperature the glow plug control module thinks the coolant is? Or if you had a turbo model how much manifold pressure the ALDA is seeing? Or the requested vs. actual position of the fuel rack / quantity adjuster (Ok, some models do have a sensor on this, but you'd have to use an ohm meter to probe it). I have access to all of this data and more on even the old 1996 cars, and moreso on my 1999. The data available on the latest cars is mind boggling!

You also mention aluminum heads being a "weakness". Howso? Yes, you can't overheat them as much as an old iron head. So? I don't plan on overheating my cars if I can help it Yes, some cars have had design issues with the aluminum heads.... they were new in the 70s/80s. I bet when cast iron heads were new they had some problems too. But being lighter they make the car faster, use less fuel, and make it easier to service (have you ever tried to pick up a cast iron cylinder head? I was used to aluminum VW ones and nearly hurt my back )

Now don't get me wrong, I love the old diesels too. I've owned several. They have their charm, and when adjusted properly they can run smoothly and efficiently. But I don't see them as more / less reliable then modern technologies. They are just different.

-J

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1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

I agree, it's a case of apples v. oranges. I prefer old cars myself (diesel or gas) because they have more character. New cars are less likely to break down on any given day but are likely to be more expensive to fix when they do. I would prefer to have my kids in newer cars, I'll stick to the old ones.

Comparing the Mercedes with Iron Heads to the ones with Aluminum heads it is clear from the Threads the Engines with Aluminum Heads have more leaky Head Gasket issues, more likely to have a crack, and that you are at risk of breaking off a Glow Plug in the Head when you try to remove them.

Since VW was mentioned my Volvo Diesel Engine is made by VW. It has an Aluminum Cylinder head. In the FSM is allowed to have a certain width of cracks between the Valve Seats! And, mine does have those cracks but has been running like that since 1992.
(What I find odd about the Aluminum Cylinder Head issue is that Air Cooled Diesels like Duetz an Halets and the like do not seem to have Cylinder Head issues like the Water Cooled Aluminum Heads do.)

With the Black Box issue concerning Computer Controlled Engines it is clear that when trouble does happen it is going to take a better trained Person and most likely more Equipment to trouble shoot problems on it. It has been like that with gas Cars for many years.

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84 300D, 82 Volvo 244Gl Diesel

Yes, the 80s 4 5 and 6 cylinder VW IDI motors do like to develop cracks between the valves, but it doesn't really affect anything. Glow plugs getting stuck in the 606's head is a problem I'd forgotten about.

I wouldn't call the computers a "black box". It's not fair to call torx fasteners complicated if all you had was a flat blade screwdriver, similarly you just need the right tools to test and fix modern electronics. I'd hardly consider myself a "trained person" in that regard, anymore then most of us shade tree mechanics could consider ourselves trained on mechanical systems. I've just done my reading and fiddling, so I understand how they work.

-J

As one that loves old cars and embraces technology and all it has to offer, I have to say I am in the middle here. I like things to be simply, but yet I like them to be adaptive. The best example I can give is that what I prefer in my ideal auto is simplicity with respect to the chassis and all of its 'works', and a drive train that is adaptive to changing conditions, giving me the most power when I want it, and the greatest efficiency when I dont. This same technology can tell me what it going on with any system in the drivetrain and alert when a parameter is outside the norm.

Example of a great car, a W123 with an OM606 and a manual trans. This is a subjective opinion, but one I find pleasing.

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83 300TD (need rear wiper assembly dead or alive)
84 300SD Daily driver
85 300TD almost 400k miles and driven daily.
98 E300D *sold
86 300SDL *sold and made flawless 10 hour journey to new home.

Marine diesels, as a general rule, are ran at a more constant RPM, no gears to shift, load doesn't change much, as in going up a hill. Automotive diesel designers must consider weight, not a big factor on a commercial boat so oil sumps, filter canisters etc.. can be bigger. The old direct revisable engines, Atlas, Washington, Enterprise for example weigh tons. The 120HP Atlas is probably six feet tall and twelve feet long. They lasted forever and aside from the fact they needed "manual" oiling every 3 or 4 hours, required little maintenance. Its hard to compare a marine diesel as the playing field (or sea state) in not even.

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1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"

Manufactures typically over-design a product when it is first brought to the market. With time others compete, the customer becomes more accustomed, the manufacturer knows more about both the market and the technology and a product that could comfortably run for 20 years now lasts 7.

This is a very typical cycle.

Now we can sit here today and say the MB diesel 123, 124 and 126 (other models as well but these 3 seem dominant here) have a proven track record of success and longevity. Can the same be said about the 210 & 211? 10 to 20 years from now we will know more than today.

But one thing seems clear (or maybe it doesn't and I'm in error); the MB of today do not appear to either be designed for DIY and it's questionable that they are built with the same level of over-design and potential longevity.

It appears that MB changed sometime in the '90s from a company comfortable with a unique market philosophy and approach to a company that believed they needed to beat the Asian (and probably others) competitors but emulating more of their methods.

So I can't say all cast iron and a mechanical injection pump makes a diesel a diesel but I think I can say that the older MB encompassed a design philosophy that I embrace and I am uncertain that the newer ones follow the same approach.

For my money the n/a 603.912, which represents the last purely mechanical luxury saloon car diesel engine on the planet, and ditto the 722.415 transmission, represent the pinnacle of refined light duty diesel engineering.

No saloon car diesel engine made before or since comes close.

The modern products are inferior, again, there is nothing inherently wrong with a computer controlled engine, provided you build it up to a standard, but when even MB build it down to a price then you end up with a substandard product.

I'll say the same thing for the mid 80's Japanese motorcycles, materials, castings, design and machining were at the pinnacle.

when it comes to heavy duty traction diesels my money will always go on Gardner, cat used to be fantastic up until the 80's, then they also went cheapo computer control.

bigger diesels 2000 bhp and up as fitted to ships / trains and static are in a different league.

detroits, everyone talks about the toys, the 71's, heap of crap, but the 92 series were a decent enough engine, if well maintained... but cat + twin disc always beat detroit + allison hands down.

I have this argument time and time again, not on diesels but gassers. Take my 96 rover as an example. The engine is basically a buick 215. Rover did some upgrades to that engine over the years to make it a little more reliable, but it still the same engine. Then came the computers. 96 saw the addition of the Gems management system. Electronic/ sensor controlled injection, timing etc. It makes it almost impossible to work on these trucks now.

Sure you can have all the data you could ever want by hooking it up to the computer... but the computer cost 5k used, over 10k new... Only dealers and specialty shops have them and believe me they charge for it. 150 bucks at the dealer just to plug it in... not actually do anything, just plug it in... Plus you loose the truck for a week while they read the data from the computer.

Sure you have the OBDII scanners, but the info passed is most time worthless... just good enough to tell you you SOL. take a problem I have been personally battling for over 6 months. My 96 runs rich... very rich, to the point of fouling out the plugs in about 9 miles rich. Black smoke pours out the back. The only code the truck throws is p1316.. which is a numerical way of tell me the trucks running rich... duh. Armed with this vast amount of data I have so far replaced the IACV, the TPS, the injectors, The O2 sensors,, cleaned the MAF, Done compression checks, leak down tests, vacuum tests, fluid tests, replaced the cats, and I can still not get the truck to run. So it sits in my driveway.

Took it to a specialist... who kept it over a week, and didn't hook it up to the "testbook". So I was no closer to finding out the truth than when I started. Why didn't he hook it up? he claimed it was too slow. More often than not, your simply tossing parts at a problem with these "newer" cars until it magically disappears. Guy like me, so called specialists and even the dealer ships themselves. Only 1 time have I ever taken a car to a dealer who was able to fix a problem the first time. That was a cadillac dealer in cincinnati fixing my 2004 SLS. Course, it was under warranty. (ended up being a total rebuild of the engine due to a design flaw in the north-star engines of that year) But they diagnosed it and fixed it first time. Every other experience I have ever had with computer controlled cars has been the same part tossing story. Its the main reason I'm going back to the mechanical cars of the 80's. And the reason I'm most likely going to pull that piece of crap 4.0 out of my rover and put a 617 in it.

"Mercedes 3.0 606 6 cylinder. Both motors are known for their power, smooth running, and longevity'----
The 3.0 v6 hasnt even got its real teeth yet in longevity terms-- you might want to wait 22 yrs more before seeing it that is even a fesable valad thing to post. Uh-oh Edit---i read it too quickly--i didn't see the 606 part. anyway the v6 is cosidered (expected)by some a throw away after x yrs

Holy quotes batman !

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83 300TD (need rear wiper assembly dead or alive)
84 300SD Daily driver
85 300TD almost 400k miles and driven daily.
98 E300D *sold
86 300SDL *sold and made flawless 10 hour journey to new home.

It sounds like a case of KISS ; Keep It Simple Stupid.
The older motors are so simple in their operation & control.
As soon as you have an electronic/ mechanical interface you have a potential problem.
Electronic gear does not have the longevity/reliability of the simple mechanical stuff.
The motor area of a car is a horrible place for anything electronic. The simple solution for the designer is to seal it up & make it not repairable. Often it may only need a joint re-soldering. Even fuses have problems!!
How long did your last computer last?
As soon as bean counters (accountants) get involved in mechanical design things no longer last. The throw away concept is now apart of most modern cars.
They need us to come back & buy another new one in a few years.

The concept of just replace everything is the incompetent mechanics easy way out.
If they could only charge you for the part that actually fixed the problem, they would have to lift their game. I once rewound a starter solenoid for a neighbor so he didnt have to replace the starter on a stationary engine. Saved him nearly $1k & a 2 week wait. The dealer said he could not do it as there was liability.

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Grumpy Old Diesel Owners Club group

I no longer question authority, I annoy authority. More effect, less effort....

1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
Other toys ~J.D.,Cat & GM ~ mainly earth moving

If you lived in a climate like crete or southern spain (or texas) you would probably have to rethink that about the 60x.