Today, the high here in Edgewood, NM is 21 degrees. It has gotten into the negatives recently.

The last few days I've started up my 1972 220D easier since changing the oil to 5w40 Mobil 1 Turbodiesel Truck. It will turn over much easier than back when it had the 15w40 dinosaur oil in it.
Anyway, starting in the cold weather is still difficult due to fuel delivery, I'm sure. Since I'm about to drive 2000 miles east starting on Monday, I want all the advantages I can get in starting the car and delivering fuel.

The OM615 and early 616 engines with the pneumatically governed IP don't draw warm oil off the engine so they take a while to really smooth out, or at least mine does. Maybe 8 minutes. Since the IP has its own oil sump, it doesn't heat up like the later pumps.

Right now I've got 30wt monograde dinosaur oil in the IP. Is it reasonable to think that I may get a bit better starting and performance out of either a monograde 30wt synthetic or a lighter mono dinosaur oil? Granted, the IP oil does thin out with diesel fuel and I'm thinking that the very high viscosity of the 30wt dino oil is allowing more diesel past the seals until the IP warms up.

At 20 degrees F, 30wt dino flows like very cold molasses and I can't think it's lubricating much as I think it's restricting movement of the cam and valves in the IP.

Am I on the right track here?

If I change it for the cold weather to either a lighter dinosaur or a synthetic, I will obsessively monitor the temperature. i already change it out way too often (according to a few friends) but I figure a few oz of oil is cheap enough that I can change the IP oil every month then just pour it back into the fuel tank and burn it.

Any opinions?

Phil Forrest

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1972 220D "Trudy," named by a friend.

"The 220D sounds good... I suspect it is the only car that you need a calendar for, rather than a stopwatch, when doing acceleration tests."
Tom Abrahamsson

Again, this is for the injector pump which has its own oil supply independent of the engine. Stock, it's supposed to take 30wt under normal temperature conditions. The oil is supposed to be a monograde, not multigrade since the IP does not heat up like the engine.

I can't find any MB recommendations on what oil should be used in very cold conditions where the high temperatures are only in the 20's.

Also, I have two Mercedes with engines that have a lot of compression and very low blowby. I use 5w40 synthetic in both and neither burn nor leak oil because my engines are in good condition and I obsessively maintain them. You've stated synthetic oil doesn't work for you but it works for many other MB owners, myself included.

All that said, oil today is vastly improved over oil from when the factory service manual was written, so while those recommendations may be fine, there is a much greater availability of higher quality oils for our cars.

Phil Forrest

__________________
1972 220D "Trudy," named by a friend.

"The 220D sounds good... I suspect it is the only car that you need a calendar for, rather than a stopwatch, when doing acceleration tests."
Tom Abrahamsson

My issue does not affect you since you have a later type of injector pump.
You do not have to change your injector pump oil. It is lubricated from the engine sump.
The injector pump can't use a multigrade oil because it doesn't get hot like the engine.
I've said this three times now. The pneumatic IP uses a MONOGRADE oil and the viscosity and lubrication properties of monograde oils ARE temperature sensitive, that's why we have multigrade oils!

Phil Forrest

__________________
1972 220D "Trudy," named by a friend.

"The 220D sounds good... I suspect it is the only car that you need a calendar for, rather than a stopwatch, when doing acceleration tests."
Tom Abrahamsson

You could probably put 90wt gear oil in there and it wouldn't affect cold weather running on this engine. These pumps take a very minor amount of oil, and it's just intended to splash around and lubricate the governor, rack, cam and plunger assemblies. I wouldn't bother worrying about it

All oils are hygroscopic, especially the lightweight ones like your 3 in 1. They attract water molecules from the atmosphere. Also, the 3 in 1 is not an oil you use to lubricate your engine.

Your 15w40 was fluid because it is meant to be fluid in cooler weather but 15w40 makes turning the engine over in weather below 15 degrees much more difficult. That is why folks go to lighter weight oils in the winter.

You never have said anything about operating a car with a pneumatic injection pump. If you had read your owner's manual for that car with the pneumatic IP, you'd see that it recommends 30wt monograde oil. But 30wt is not optimal for temperatures that are consistently below 20 degrees. Especially in a system that does not heat up like the engine does.

So, instead of continuing to say that I've made the wrong oil choices, in spite of them working for me quite well, could you either provide some constructive comments or just stay quiet? Sorry, but I shouldn't have to explain all this time and again.

IP uses 30wt at normal temperatures. It's winter now and VERY cold.
IP doesn't heat up like the engine so the oil doesn't reach an optimal lubricating temperature like it does in an engine.

I'm using synthetic 5w40 because it works for me and right now it's extraordinarily inexpensve. So please provide some constructive comments, specifically related to cold temperature operation of the pneumatically governed IP or just sit back and let others chime in.

Phil Forrest

__________________
1972 220D "Trudy," named by a friend.

"The 220D sounds good... I suspect it is the only car that you need a calendar for, rather than a stopwatch, when doing acceleration tests."
Tom Abrahamsson

Phil,
I have a couple of diesel engines (non MB) that have IP's with their own oil, I use ATF in them. Never had a problem.

__________________
Grumpy Old Diesel Owners Club group

I no longer question authority, I annoy authority. More effect, less effort....

1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
Other toys ~J.D.,Cat & GM ~ mainly earth moving

WOW! Those are probably squeaky clean inside!

Thanks a bunch!

Phil Forrest

__________________
1972 220D "Trudy," named by a friend.

"The 220D sounds good... I suspect it is the only car that you need a calendar for, rather than a stopwatch, when doing acceleration tests."
Tom Abrahamsson

Cooljjay,
You have got to be kidding.
I never wanted to be the "alpha male" of a discussion thread. I don't care. If I knew the answer to my question, I wouldn't have asked it. If you had the answer to my question, I'd have thanked you and that's that.
It IS a discussion forum but after a few explanations of what knowledge I'm seeking and getting the same answers plus a THIRD insinuation that my use of synthetic oil in my engine was the wrong choice, it got pretty tiring.
So now you're just getting nasty and you still don't have an answer to my question.
I'm not saying stay out of my threads, just don't keep harping on the same thing that doesn't actually answer the question that has been posed.

Phil Forrest

__________________
1972 220D "Trudy," named by a friend.

"The 220D sounds good... I suspect it is the only car that you need a calendar for, rather than a stopwatch, when doing acceleration tests."
Tom Abrahamsson