A good friend of mine just purchased a clean well maintained 1985 MB 300SD it's turbo diesel of course. I think it's the 3Litre I6,some of you MB guys may know for certain,anyway we are looking for oil recommendations for it and btw it has 182xxx miles.We are leaning either 10-30 or possibly 5-40 Rotella can we do better than these,it will be his daily driver when everything is completed.
Oil for older MB 300SD?
- Thread starter 4ever4d
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'85 should be the OM617 3.0l I5 turbo diesel, good oils include Mobil 1 Turbo Diesel Truck 5W40, Delvac 1300 15W40, Shell Rotella T6 5W40, Rotella T5 10W30 syn blend, Rotella T 15W40, Delo 400 LE 15W40 or 10W30, pretty much any name brand diesel oil will work OK in it. I run Delo 400 SAE 30 CH-4 in my 300D in summer (got a ton of it on closeout from AutoZone for 99 cents/GALLON), either Valvoline Premium Blue Extreme 5W40 or Valvoline Synpower 10W30 in winter.
Thanks bullwinkle,he and i are new to MB and are kinda learning as we go,he is in it for a good car and i'm just having fun playing with a new toy.I did notice that we are on the right track with our thinking on oil.
Those are good oils but I don't think I would use the 10w30 because it probably too thin at higher temperatures. Go with the 15W40's or 5W40's.
I ran my old 200D on Full synthetic 5w-30 Diesel for years with no problems.Even with wide open use for hours on end the oil did fine.
I would have no second thoughts about Amsoil HDD 5w-30 or Rotella T6 5w-40 in these MB engines.
Years ago 15w-40 was very popular in Germany for these but that was before lighter weight synthetics gained widespread acceptance among the "its to thin crowd".
I noticed an increase in top speed of over 10 kmh and much easier staring as opposed to the 15w-40 my grandmothers dealer used in the car.It was much smoother and quieter also.That dealer even commented on how much better it ran and concluded the lighter oil in this engine may not be so bad after all.
Today hardly anyone uses the 15w40 in their old MB diesels.
I would have no second thoughts about Amsoil HDD 5w-30 or Rotella T6 5w-40 in these MB engines.
Years ago 15w-40 was very popular in Germany for these but that was before lighter weight synthetics gained widespread acceptance among the "its to thin crowd".
I noticed an increase in top speed of over 10 kmh and much easier staring as opposed to the 15w-40 my grandmothers dealer used in the car.It was much smoother and quieter also.That dealer even commented on how much better it ran and concluded the lighter oil in this engine may not be so bad after all.
Today hardly anyone uses the 15w40 in their old MB diesels.
Thanks for all the responses,after a short discussion i am almost certain he is going to run the Rotella 5-40 syn and possibly do a uoa to see how well it's working.This old MB is in great shape and with a little tlc will serve him well for several years to come.
I bought the same car a few months ago.
Many recommended 5000 mile OCIs with 15w-40 which happens to be the 1985 manual's recommendation. Synthetic was recommended for winter driving. There are enough of these cars running with well over 300K on the clock to justify running dino without worry.
Many recommended 5000 mile OCIs with 15w-40 which happens to be the 1985 manual's recommendation. Synthetic was recommended for winter driving. There are enough of these cars running with well over 300K on the clock to justify running dino without worry.
Mine was a 1982 and the owners manual specified the same 15w-40 but that was almost 30yrs ago when that was written.
Oil technology has come a long way in that time.
Oil technology has come a long way in that time.
With newer turbodiesels I always recommend a synthetic diesel-rated oil, usually a 5w40. But for older MB diesels, they seem to run very well with conventional 15w40 oils.
I cannot recommend an Xw30 oil in any diesel engine. Yes, I know some owners have had good results and good used-oil tests, but they seem to be in the minority. Older MB diesels generate more soot, so they need a very robust oil with a high initial TBN.
I cannot recommend an Xw30 oil in any diesel engine. Yes, I know some owners have had good results and good used-oil tests, but they seem to be in the minority. Older MB diesels generate more soot, so they need a very robust oil with a high initial TBN.
For update purposes he has done the oc with 5-40 Rotella T6 after speaking with him at lunch today it is running smoothly and he may be doing uoa if he does i will try to post thanks again for all the response.
JHZR2
Staff member
Rotella 5w-40 is a great choice.
Originally Posted By: Tornado Red
I cannot recommend an Xw30 oil in any diesel engine. Yes, I know some owners have had good results and good used-oil tests, but they seem to be in the minority. Older MB diesels generate more soot, so they need a very robust oil with a high initial TBN.
Huh?? This would be BIG news to our friends north of the border in Canada, who run ZERO W30 Esso XD-3, sometimes year-round, in diesel trucks. Pretty much every manual I've read, from the 6.0 Ford Powerstroke turbo, to my old 7.3 IDI Ford, and the 6.2 GMs, recommend a 10W30 for winter use in below freezing temperatures. BTW, TBN depletion is caused by short trips & moisture buildup in oil, causing acid (which depletes the alkaline base, usually sulfated ash)-pretty sure it has NOTHING to do with soot! I can also state from personal experience-without a block or oil pan heater, conventional 15W40 or even 10W30 doesn't work well AT ALL in a HEUI engine in cold weather! Engines don't START very well in an old Mercedes with them either!
I cannot recommend an Xw30 oil in any diesel engine. Yes, I know some owners have had good results and good used-oil tests, but they seem to be in the minority. Older MB diesels generate more soot, so they need a very robust oil with a high initial TBN.
Huh?? This would be BIG news to our friends north of the border in Canada, who run ZERO W30 Esso XD-3, sometimes year-round, in diesel trucks. Pretty much every manual I've read, from the 6.0 Ford Powerstroke turbo, to my old 7.3 IDI Ford, and the 6.2 GMs, recommend a 10W30 for winter use in below freezing temperatures. BTW, TBN depletion is caused by short trips & moisture buildup in oil, causing acid (which depletes the alkaline base, usually sulfated ash)-pretty sure it has NOTHING to do with soot! I can also state from personal experience-without a block or oil pan heater, conventional 15W40 or even 10W30 doesn't work well AT ALL in a HEUI engine in cold weather! Engines don't START very well in an old Mercedes with them either!
15w-40 Rotela or Chevrons Delo 15w-40 is what I use on my Mercedes 1979 300sd. I never add oil between oil changes. Tried several synthetics and even other non synthetics and none seem to keep their level as well as the above mentioned. Once used a valvoline diesel oil and was surprised on how much oil I had to add between oil changes, it was terrible. Just adjusted the valves and getting an average 28 mpg. Solid car
Rotella 5w40 is a great oil. I use 15w40 Delvac in mine.
i'm pretty serious about getting a 300 series diesel mercedes soon. i hope to run it on used cooking oil and that whole bit.
i wonder if 0 w-40 mobil 1 would be a good oil to run year round. then again i see as much as a 90 degree temp. difference where i live between winter and summer.
i wonder if 0 w-40 mobil 1 would be a good oil to run year round. then again i see as much as a 90 degree temp. difference where i live between winter and summer.
JHZR2
Staff member
Nope, run a 5w-40 diesel spec. Youll need an older w123/126 with a 616/617 engine to do what you are saying.
Id highly recommend blends versus trying to run straight. You can do more damage than good sometimes.
Id highly recommend blends versus trying to run straight. You can do more damage than good sometimes.
Not so sure about needing the high TBN, low sulfur diesel means low sulfuric acid. It also offers (demands?) the opportunity to add all sorts of yummy stuff to your fuel for lubricity.
My 165k 240d, with delvac 15w40, had slightly over 2 bar of pressure at lowest hot idle speed. Otherwise it was pegged at 3 bar. A 30 weight would have been fine. Its rear end ratio was so short the motor was screaming at 55 mph and would have made adequate pressure on anything. I understand the turbo 300s have taller gearing, but with an automatic you'll never lug the motor.
My 165k 240d, with delvac 15w40, had slightly over 2 bar of pressure at lowest hot idle speed. Otherwise it was pegged at 3 bar. A 30 weight would have been fine. Its rear end ratio was so short the motor was screaming at 55 mph and would have made adequate pressure on anything. I understand the turbo 300s have taller gearing, but with an automatic you'll never lug the motor.
Originally Posted By: JHZR2
Nope, run a 5w-40 diesel spec. Youll need an older w123/126 with a 616/617 engine to do what you are saying.
Id highly recommend blends versus trying to run straight. You can do more damage than good sometimes.
whats the difference? the injector pump? the nozzles? why couldn't i run veg oil?
and thats the motor it would have is a turbo om617 inline 5 motor.
Nope, run a 5w-40 diesel spec. Youll need an older w123/126 with a 616/617 engine to do what you are saying.
Id highly recommend blends versus trying to run straight. You can do more damage than good sometimes.
whats the difference? the injector pump? the nozzles? why couldn't i run veg oil?
and thats the motor it would have is a turbo om617 inline 5 motor.
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Originally Posted By: jmaster
Originally Posted By: JHZR2
Nope, run a 5w-40 diesel spec. Youll need an older w123/126 with a 616/617 engine to do what you are saying.
Id highly recommend blends versus trying to run straight. You can do more damage than good sometimes.
whats the difference? the injector pump? the nozzles? why couldn't i run veg oil?
You would need a two-tank system, starting on #2 diesel and then switching back to it before shutting down the engine. If you try just pouring veggie oil in the regular fuel tank, you would be asking for some serious and expensive trouble.
Originally Posted By: JHZR2
Nope, run a 5w-40 diesel spec. Youll need an older w123/126 with a 616/617 engine to do what you are saying.
Id highly recommend blends versus trying to run straight. You can do more damage than good sometimes.
whats the difference? the injector pump? the nozzles? why couldn't i run veg oil?
You would need a two-tank system, starting on #2 diesel and then switching back to it before shutting down the engine. If you try just pouring veggie oil in the regular fuel tank, you would be asking for some serious and expensive trouble.
JHZR2
Staff member
In MB manuals for those sold in the tropics, the manual states that palm oil is an acceptable substitute for diesel fuel.
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