gonesailing13
Senior Member
I’ve been using straight 30W Rotella oil in my Lehman 135. Had some engine work done on the boat and my mechanic told me i should be using a heavier oil. Not sue what to go with.
Here's the challenge. The "book" is over 40 years old these days. The oil certifications it would have recommended have long since been superceded. But probably would say something along the lines of straight 30-weighr.Do wat de book sez.
Does the winter weight on a multi-weight oil really matter when its 85 degrees out? I never run the boat below 50 degrees F.
The bearing clearances and seals were designed to a specific viscosity oil spec.
Old original engines like the oils they grew up with. Deviate from that at your own peril.
The bearing clearances and seals were designed to a specific viscosity oil spec.
Old original engines like the oils they grew up with. Deviate from that at your own peril.
Sure seems like lots of people run the modern 15W40 oils and have never had issues after thousands and thousands of hours.
I think this is another one of those legends that may need more scientific proof than just "legend opinions".
On this topic, I will stick with anecdotal info as there is not a lot of scientific studies out there.
The bottom line is I have never heard of someone running any of the better grade 15W40 oils in the older diesels and having a problem they can trace back to the oil before the engine died of other causes.
If that info is out there, I would love a link to it for future reference and to change my tune.
The book was written 65 years ago. There have been a few improvements made to oil formulations since then. A straight grade oil is inferior to modern multi-grade oils.Do wat de book sez.
Yes, it does matter cuz the oil reaches the parts to be lubed sooner.Does the winter weight on a multi-weight oil really matter when its 85 degrees out? I never run the boat below 50 degrees F.