What grade of oil do you use in the winter time? - Page 3 - PeachParts Mercedes-Benz Forum

BillGrissom · #31 12-11-2014, 06:37 PM

My 1985 300D became hard to start around 320K miles on cool mornings (30F, never gets real cold here), even w/ a block heater (on car when bought at 280K, perhaps indicated a problem since car was always around here), and not at all without. I usually used 10W40 Rotella. Glow plugs were good and I would leave on 20 sec, then again when I heard them click off. Compression was ~250 psi in most cylinders (poor). The engine failed at 330K, w/ chunks missing from some pistons and around the grooves.

I now have a used 1982 engine in that car. It starts fine as soon as the glow plug light goes out (usually 5 sec here), as does my 1984 300D. Both have excellent compression (~400 psi). You can judge the engine wear pretty well by blow-by. See youtube. If you see a lot of puffing out the oil fill hole (my 1985 before), a good guarantee the rings are worn. A diesel won't start at all at certain temperatures, depending on the compression you have. Ambient temperature & compression => cyl air temperature when fuel sprays. There is a minimum temperature needed to ignite the diesel spray. Spinning the engine faster while cranking helps. Longer glowing and longer cranking helps heat up the cylinder walls.

landev · #32 12-11-2014, 10:36 PM

I use this year around in both my Mercedes Diesels, my BMW LT scooter, JD 970 Tractor, Saber yard tractor, DR field trimmer, Polaris Diesel and Honda Rancher ATVs... virtually in every thing other than my 335D BMW which is still under warranty. This oil works very well in all my applications and is fairly affordable (on sale at NAPA once a year @ $20/gallon. Don't fall for the BS that you need to use a specific brand (e.g. Mercedes, BMW, etc..) Also, nothing wrong with using this higher spec-ed oil in machines calling for your run of the mill oil.

-l-

dubadxx · #33 12-13-2014, 12:55 PM

I just changed my oil in the 240d and the 300d less than 1k mi ago. I was wondering if anyone has lowered the viscosity of 15w40 by adding something like Marvel Mystery Oil in the winter. They definitely fire up easier with a synthetic. I've used Pentosynth 5w40 or LubroMoly in the past, but they are a tad expensive.
I added the 15w40 back in the spring, don't drive em much in the summer, A/C issues and all. But the 300d is my winter beater, snow tires, 200lbs of salt in the trunk. NO block heater! As usual, didn't get around to installing the lower hose radiator heater this year. Prolly won't snow anymore.