How hard are short trips on MB diesels? - PeachParts Mercedes-Benz Forum

Joe Diesel · #1 10-31-2007, 12:54 PM

I have been looking into purchasing an 80-85 300SD next Spring to replace a car that gets driven about 7500miles a year. Will driving this little mileage per year wear the MB diesel (engine in particular) faster, slower or the same as higher mileage. A lot of the driving we do would be short trips around town in the winter which would be less than 2 miles (this car will not be a commuter since we don't commute). I am wondering since a friend who has a TDI and I were talking and he was concerned about the engine not getting up to temperature before being turned off. I said, well my other cars haven't complained, but they have all been gassers. Answers?

#2 10-31-2007, 12:59 PM

Yes. That is considered extreme operating conditions for any engine, not just MB diesels. The engine won't have time to get warm and the oil won't have time to get hot and boil out moisture.

bustedbenz · #3 10-31-2007, 01:06 PM

The main results will be what ForcedInduction said plus

1. A byproduct of combustion is H20. This will condense in your exhaust and cause premature rusting and wearing out of the exhaust system towards the muffler end, if you don't let it get up to temp to boil that water out.

2. Possible "plug fouling" of diesel injection system. I know there's no spark plugs but it's the best example.

All these problems should be fixed if you'll just give it a good hard run on an interstate somewhere every week or two. Just get everything good and hot and blown out, and it should be fine if you maintain it that way. Maybe consider shorter than usual oil change intervals if you're a mileage pusher.

rrgrassi · #4 10-31-2007, 01:14 PM

Short trips like that are hard on any internal combustion engine.

Diesels really need to be driven.

I did have a gasser that did not like the city living. I moved from the rural area to the city. Drive distance to work was 3 miles. Every week I would take a highway run, but I did notice after 3 months, the engine did not run as smooth, power dropped and fuel consumption increased. After two years I was able to move back out to a rural area (I hated and still hate city living). The vehicle was back to it's happy self soon after. BTW regular oil changes and tune ups were performed. I had to rebuild the carb every 6 months while living in the city. Spark pluges fouled quick and the cap/rotor fouled quickly also.

junqueyardjim · #5 10-31-2007, 01:19 PM

I think you have to look at it like this. Short, cold weather trips are hard on any of our fueled engines. If it burns gasoline or diesel, they just don't like cold - period, and so you just have to work around it. If I was going to do that type of driving and I really wanted the engine to last, I would keep the engine heater plugged in most of the time, I would be tempted to idle the engine as much as possible at short stops. Not always possible as a running vehicle is easy to steal and some communities will even ticket an idle vehicle if the operator isn't around. I would also change the oil often, probably as often as 1000 miles in very cold weather with a lot of starts but very little mileage. I wouldn't always change the filter, probably would do that every 3000 or 4000 miles. If the cooling system is good, I would look into removing the fan for the whole winter season. They are cool runners, I drive mine around central Indiana often with out the fan. If it doesn't overheat, and won't if everything is in good shape, it is very good for the engine and is good for extra mileage also. For January and February in Wisconsin, I think you could easily make a cardboard type closure for the front of the radiator that is somewhat easy to open up or close up. Again it will bring engine temperatures up quicker and a little higher. Always keep an eye on that temperature gauge - actually if you are a good operator you can usually smell overheating very quickly.

Maxbumpo · #6 10-31-2007, 01:32 PM

A diesel engine will not tolerate this life very well; a gasoline engine would do better. Short trips that don't allow the engine oil to fully heat up (requires at least 15 minutes of driving after the coolant reaches normal temperature) will allow water to remain in the oil. Also, inadequate heat in the pre-chambers means incomplete combustion means additional soot deposits and poor fuel mileage.

Diesel engines make great sense if you drive a lot of highway miles. I'd recommend finding a nice 124 300E or 201 190E for your use.

Rmcfarland · #7 10-31-2007, 01:38 PM

I drove my 240D in the city last winter, every day (weekday, at least). I would try and clean it out on the highway once a week or so. Get it up to temp, and then give it a good 0-60 run, topping the gears. Mine blows a cloud out the first time i do this in a while.

The other problem I did run into was the battery had a hard time getting a good charge, glowing +1min every start in the cold and then running 10 minutes or whatever. Keep a charger on it when you can. Block heater would help too, I'm gettin me one o' those for this winter. Maybe even a battery heater if you are in a colder climate.

Joe Diesel · #8 10-31-2007, 02:14 PM

I should say that for my car and truck, I change the oil and filter twice a year (the oil and filter service interval according to the owners manual for the car is every 6000 miles and the truck 7500 miles, but I consider our type of driving extreme on the engine). I put ~7500miles on the car and ~1200 miles on the truck each year. I follow the time table rather than the mile table for service.
I won't be aquiring a MB diesel until after the snow is gone so I will have the summer to check this out and get ready. The glow plug/battery issue will be interesting to check.
What am I getting myself into?

patbob · #9 10-31-2007, 02:26 PM

Quote:

Originally Posted by Rmcfarland

Keep a charger on it when you can. Block heater would help too, I'm gettin me one o' those for this winter. Maybe even a battery heater if you are in a colder climate.

Maybe permanently wire in a trickle charger for the battery with the block heater so it charges and keeps the block warm.

Hatterasguy · #10 10-31-2007, 02:28 PM

My brokers 300SDL has done nothing but short trips, mostly city driving since it was new, 205k miles and still going strong.

Seems to bother the trans more than anything, they only seem to go about 100k in that duty cycle.

Ara T. · #11 10-31-2007, 06:38 PM

I drove my 300D 10 minutes to school every morning with a faulty thermostat for 2 years, the temp barely got to 60 degrees celsius. I changed oil every 3K miles but it would start up every morning with barely a crank.

H-townbenzoboy · #12 10-31-2007, 06:51 PM

I think they're built to withstand such abuse. Just take a look at the W123s still being used today as taxis. How many 70s and 80s American autos do you see still in taxi service? (though I saw more than a few in DC recently).