I bought a '90 300D 2.5L turbo this past summer. I use to own an '81 300D N/A so it interesting to compare the w123 to the w124.

When the guy sold it to me he said, "You can take a couple gallons of clean vegetable oil, pour it in the tank and drive away. You can't do that with a 123."

Is there any truth to what he said? Is there some reason that the later 5 cylinder can better combust WVO?

Hoping to learn something!

No truth to that at all. For better or worse, all around the world, people have been dumping varying percentages of vegetable oil into W123's and driving away for 30 years.

Now Im not saying it's a *good* thing to do under all (or any) conditions, but there should be no difference in the ability of a W123 or a W124 to burn a low percentage blend of SVO and diesel.

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'85 300D, 'Lance',250k, ... winter beater (100k on franken-Frybrid 3 Valve Kit)
'82 300D, 'Tex', 228k body / 170k engine ... summer car
'83 300TD Cali Wagon 210k, wife's car

The science papers that I've read says you can mix 20%VO/80%D2 without doing any harm to the engine. This is without heat. Go any higher than a 20/80 mix and you'll start doing damage.

Here is an article form the Univeristy of Idaho about it - http://www.peachparts.com/shopforum/attachments/diesel-discussion/76989d1265051449-science-running-veggie-oil-one%2520tank-idahovegoilslitreview%255b1%255d%5B1%5D.pdf

Most people would argue that the 123 is more durable for VO use that a 124, but I dont' know if thats really true or not. People do it in both. People do botch jobs on both and kill cars while other do it right and run VO successfully for long time periods without problems.

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I 'ppreciate the feedback.

I always hate to repeat something I've been told without knowing if it is correct.

Take care.

There are quite a few that run on 100% VO single tank (no VO system) on a W123 diesel in warm weather and get away with it for a while. How long? I have no idea since I have no personal experience. I would like to try it IF I have an engine that is disposable but I do not have one at the moment. The W124 diesel's have a similar injection pump as the W123, which has one of the toughest pump for WVO since it is lubricated by engine oil, which helps to heat the VO in the IP. How different are the injectors and pre-combustion chambers in W123 & W124? On the W123, the injector spray pattern is very narrow and sprays at the hot ball in the pre-combustion chamber and that helps to burn the VO. That may be a reason (I have no prove, however) that it works so well with VO. Does the W124 have a similar pre-combustion chambers?

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

The w124 precumbustion chambers also have a ball that the injectors spray on. I do not know the angle of the spray degree.

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2011 e320 cdi (132,000) current
2005 Jeep CRD diesel--2.8L (138,000 miles) wrecked, insurance took
1993 Mercedes benz 300D 2.5 Turbo Frybrid powered. (336,000 miles) wrecked and sold as parts car
1990 Mercedes benz 300D 2.5 Turbo (170,000 miles) wrecked and sold as parts car

Check out my Frybrid Vegtable Oil Conversion at http://1990300dfrybridconversion.shutterfly.com/

I took a look at your car through the link on your signature. You've done quite a bit of work. Where do you get your WVO?