1976 300D Oil
 

Hey guys, I am a new member here, I just recently fulfilled a life long dream of mine and baught a 1976 Mercedes 300D with 82,229 original miles. I absolutly love the car, but I have a few quick questions, the owners manual states that for year round use, 10w-40 should be used, however the old maintnence records show that around 1982 or 83, the dealership started using 15w-40 when they would change the oil. Is it ok to use 15w-40 in the engine, if so, that would be very convenient since my tractor uses 15w-40. lol
My other question is, incase the engine were to ever over heat, would I follow the same procedure as all my other Diesels and simply letting the motor idle and cool off?
I hope in the next couple days to buy a shop manual for the car, the two original maintnence books that came with the car are really more just record books.
I am extremely excited about owning this car, I find myself thinking about it all day long, even when I should probably be working. lol

I use rotella 15-40 or Delo 15-40 in the summer.
I use 5-40 synthetic in winter.
If you ask 20 people you will likely get 20 opinions though.
Wodnek

15W40 dino oil is fine, however, if it gets cold, say down to below 20°F or below, you may want to consider a synthetic to assist in cold starting. Depending on compression, they generally need all the help they can get down at these temperatures.

If the engine ever gets to 115°C., back off on the pedal and see if it drops off. If it remains at this temperature, or begins to climb, pull the vehicle off the road immediately and shut it down.