Thinking of buying an old diesel Benz

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I am going to Canada soon to stay 6 months and as I always wanted to have a W123 or W124 diesel MB, I think that would be the right time and opportunity to buy one.

The thing is, I know a lot of people buy these old diesel Benz and VWs just to try to run on vegetable oil and sometimes or most of the time, they just get some old McDonald's grease and put it directly on the tank. As I am planning to bring the car with me when I get back, I would like to get a car that never had anything other than real diesel in the tank.

What should I check to see if a diesel engine had burned too much vegetable oil in its life?

Thanks
 
I don't know how you could ever determine how much veggie oil it had consumed, but I wouldn't be concerned about it either.
 
Those old diesel Mercedes engines were very long lasting they would bang and tick and smoke and run rough but they would do that for a million miles...lol

Now the new Mercedes NO
 
In Canada, many are likely rusted out, but you might find one.

Users eljefino and JHZR2 on here have/have had them and will know a lot more than me.
 
You can buy Diesel at every filling station in Canada. I don't know of a single person who uses Bio-Diesel, and I know probably a hundred diesel truck owners. They just fill up at the pump, like everybody else.

Creating Bio-Diesel from used vegatable oil is somewhat more complex than just pouring it into the tank. You need at least two distinct commercial Diesel formulations in Canada ... ordinary Diesel will not run in winter.

Plus, restaurants in Canada get paid by companies who go around in tanker trucks collecting their used vegetable oil. So no-one is going around to "McDonalds" and getting free french fry oil here ... they would either say no, or call the cops on you.

Finally, Diesel engines, especially older Diesel engines, can tolerate a wide variety of fuels, without issue. So even if you somehow bought the only Bio-Diesel fuelled MB in Canada, it would run fine and you would have no way of determining if it has had Bio-Diesel in the tank.

You are seriously over-thinking this, and worrying about something that has a near-zero likelihood of happening.
 
Everyone loves the idea.
Darn near every story I've read mentions that the owner has access to some company whereby collecting WVO is made easy.

Best of luck, honestly. Kira
 
First I'd look to see if any fuel lines are recently replaced. Now old cars need them replaced eventually, so that's not a dead give-away. But if they look 30 years old then it's a sign. Also look for extra holes for filters, switching valves and the like. That far north they had to run a second tank, as WVO congeals at too high of a temp to shut down on--starting would be too hard.

After that, I think you are stuck doing the usual compression test. And sniff test of the prior owner. See if you can arrange to be there for starting after sitting all night. Old diesels are hard starters--but if they resort to ether and/or it takes forever to start, then that's a sign of wear.
 
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I would go to the Mercedes Coub and Mercedes forums on line. The true enthusiast/collector crowd. You'll find a clean, well maintained one there. You'll pay more, but the lack of heartache from getting a good one is worth it. There were literally millions of W-123 diesels sold in North America. They're great cars.
Hold out for a clean car in original condition - they're out there, among the great sea of poor, abused old Mercedes diesels.

The most expensive car you'll ever buy is a cheap Mercedes.
 
The vast majority of these would not have been run on anything but diesel from a gas station. If you have time to search, you might get a W124 from the original owner with service records too, people tend to hang on to them.
 
Look in Southern California and Arizona for a rust free example.

Then you can take it to Canada and do the rust yourself.

There are several running around our neighborhood. They smoke a bit and make lots of diesel noises but evidently they keep on running.

I think owning and driving one takes a special calling. You've got to like them to own one. If you park in the garage with your washer and dryer your friends will know when you're around even if they don't see your car.
 
Originally Posted By: OneEyeJack


I think owning and driving one takes a special calling. You've got to like them to own one. If you park in the garage with your washer and dryer your friends will know when you're around even if they don't see your car.

LOL!
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I know I've always been intrigued by the old-school W123, 124 non-turbo diesel Benz's as well. I see them from time to time on CL.

As much as I love the thought of an all mechanical diesel, the fuel is still more expensive than gasoline in my area, and these vehicles don't offer outstanding enough fuel economy to make up the difference.
 
The W123 is probably the most solid platform MB ever put out. I drove an '84 300D Turbo sedan in the fall of 1997 for a few days as a loaner car. It was kind of slow, especially at Denver's altitude, and you had to kick the pedal to get it to really move. But then it would run all day long. Doors and trunk shut with a reassuring chud! sound, the heater worked well, and it was like driving a strongbox down the street.

Sometimes, even though I loved my W126 gas sedan, I wish I'd bought that W123 instead. I might still be running it.

Be aware that the door locks operate on vacuum, so that if you have vacuum leaks you will have door lock issues. Also, the A/C is set up to always allow about 20% outside air into the cabin -- there's no "recirculate" feature on the W123 that I ever heard of. The steering, I think, is MB's old-style recirculating ball, not modern electric or rack-and-pinion. Dunno if that matters; my W123 gas coupe always steered right where I aimed it.

Look for "Pelican Parts" or "Peachtree Parts" (formerly Mercedesshop.com) on Ixquick or your favorite search engine. They have a diesel models forum, and the folks there can tell you plenty.
 
Thanks guys for all the answers.
It always amazed me to see those beaten but running W123, W124 and the Peugeot 504 in Africa and Middle East on the news. There's not so many cars out there that can take that kind of abuse for so many years.

We already had a 504 in the family, and now I feel confident enough to finally buy an old Benz. A few years ago I took a livery in Buenos Aires and the driver had just bought his W124 300D from the German embassy, and man, what a car... If I find anything like that Benz, I think I will be happy enough to not plan to buy another car for a good decade at least.
 
Rust and condition are the two biggest concerns with buying one of these.

W124's are still pretty worthless but nice W123's and W126's are creeping up in value.
 
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