Jump to content

Winter oil

Recommended Posts

I've got an '85 DM688 and I was wondering if it was OK to run 10W-30 in the winter (or all year round). I've always run 15W40 in everything but a couple weeks ago my Dodge Cummins spun a bearing and when we drained the 15w40 it was like grease not oil and I suspect that is why the Cummins had trouble. I don't want to repeat this mishap with another engine. The temperatures are running +15 during the day and 10-15 below at night. Thanks for any advice.

Link to comment
Share on other sites

The first number is the cold or winter number. There is not much difference in the viscosity between 10W and 15W. The best thing to do in the winter (extreme cold) is switch to a full synthetic oil, either a 5W-40 or 10W-30. You may experience some oil consumption with the lighter oils. So check the oil level regularly. It is okay to use 15W-40 during the spring/summer/fall months. Make sure it is a CJ-4 Diesel oil.

As for the Cummins...likely a lot of soot causing the thickness.


HOF City, PRR Country, and Charter member of the "Mack Pack"

Link to comment
Share on other sites

Thanks for all the replies. I've been using Napa Gold filters on both vehicles. I bought the oil in bulk from Bay Oil Company and I've used their products for years both engine oil and hydraulic oil. I have been wondering if the motor oil deteriorated from sitting since I've had that particular drum for a couple of years.

I'm planning to switch to Rotella 10w30 for the winter and change back to 15w40 next summer. I plan to use the remainder of that old drum of engine oil for bar and chain oil. I can't afford to ruin any more engines!

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Create New...