15w-40 vs 5w-40 in old diesel engines?

[Sberry]

We have old 60's 70s diesels. I don't run much in the winter but was wondering what might be the starting difference between 15/40 and 5/40?
Given the cost of batteries and grunt from old equipment seems like extra 10 or 20$ on a long oil change wouldn't mean squat if they spun easier?
That might sound convoluted. Probablyas easier way to say it.

 

[Brons2]

You mean like Screamin Jimmys? Or something else?

 

[eljefino]

The turbo on my 300D spun up faster on 5/40. Definitely worth it.

 

[Sberry]

Was in a hurry.

 

[ka9mnx]

Two cycle Detroit Diesels require straight 40 grade only. Straight 30 grade is acceptable in Arctic conditions. In 60's and 70's diesels I would only use 15w-40.

 

[Sberry]

We been using T6 in our 4020 a while. It was a straight grade engine and for long time didn't seem to hold hot pressure with multi. Then synthetic came and now it seems to but starting is a tuff thing to measure in different temps.

 

[Sberry]

No screamers, mostly JD and really don't winter run and do have block heat on one of I need to start.
Have an International in a loader, got heat on it but now have a little Perk that will be away from heat.

 

[cptbarkey]

Look up the first part of oil, the 5w vs 15w, therein lies the answer. It will start easier in the cold. It will however shear quicker but not to a noticeable degree.

 

[JHZR2]

The turbo on my 300D spun up faster on 5/40. Definitely worth it.

How does that make sense at operating temperature? I get it that cold starts can be improved, and maybe the response in frigid temperatures when not up to temp?



I’ve run plenty of 5w-40 in old diesels, primarily to aid in cold temperature or long-term sitting starts. Generally I’ve moved to the better flowing 15w-40 oils like delo. I didn’t put enough miles or use on many of mine to justify the cost differential.

 

[RooflessVW]

15W-40 is more better.

 

[fantastic]

We have old 60's 70s diesels. I don't run much in the winter but was wondering what might be the starting difference between 15/40 and 5/40?
Given the cost of batteries and grunt from old equipment seems like extra 10 or 20$ on a long oil change wouldn't mean squat if they spun easier?
That might sound convoluted. Probablyas easier way to say it.

Those engines probably are suffering from some lower compression by now. I'd say 5w-40 all year long. It does make a difference in the Winter for older equipment. Low mileage modern stuff it's hard to tell the difference IMO.

 

[oil pan 4]

We have old 60's 70s diesels. I don't run much in the winter but was wondering what might be the starting difference between 15/40 and 5/40?
Given the cost of batteries and grunt from old equipment seems like extra 10 or 20$ on a long oil change wouldn't mean squat if they spun easier?
That might sound convoluted. Probablyas easier way to say it.

Not enough difference to make a difference above 40f.

 

[oil pan 4]

15W-40 is more better.

Indeed.

 

[Sberry]

Better really isn't much a concern to me. It would run with whatever is in it now for as long as I am going to use it.
I was really curious about the reduction in start torque. Engines used to be changed for ambient. Makes some sense it makes some difference but I was curious about the math, only thing I have is minor experience says it works a bit better but that could be flawed.

 

[eljefino]

How does that make sense at operating temperature? I get it that cold starts can be improved, and maybe the response in frigid temperatures when not up to temp?

To be more clear, the 5w40 was better during warmup. A slower spooling turbo really shows itself then. Took the 15w40 about three miles to loosen up.

 

[Sberry]

I pulled a couple samples. Pretty much looked like a waste of money to change oil anyway. New oil wasn't even a wet dream when these were made, oil got so good they bout stopped wearing out and out use drastically reduced.
I hate oil change, modern oil, fuel inj is a gift from God