Welcome to the Hatteras Owners Forum & Gallery. Sign Up or Login

Enter partial or full part description to search the Hatteras/Cabo parts catalog (for example: breaker or gauge)
+ Reply to Thread
Page 1 of 4 1 2 3 ... LastLast
Results 1 to 10 of 37
  1. #1

    40 weight oil for Detroit's

    My mechanic is recommending Delo 400 40 weight oil for my So Calif based boat.Temps being moderate, rarely 40's mostly 60F, what would the harm be in mixing 15/40 after only using 40 weight?I know on Aircraft we typically used straight weight oils but in more recent time, the advantage to multi weights not having to change with seasons convinced nearly all to use multi weights.Thanks for opinions.
    Mitch Cohen Wilmington Ca75 YachtFish48YF363

  2. #2

    Re: 40 weight oil for Detroit's

    If your mechanic is recommending Delo 400... get another one! If he knew anything about DD he d know you can’t use Delo 400 in DD You need Delo 100


    https://www.samsmarine.com/Manuals/Delo%20400.pdf
    Pascal
    Miami, FL
    1970 53 MY #325 Cummins 6CTAs
    2014 26' gaff rigged sloop
    2007 Sandbarhopper 13
    12' Westphal Cat boat

  3. #3

    Re: 40 weight oil for Detroit's

    Quote Originally Posted by Flymitch View Post
    My mechanic is recommending Delo 400 40 weight oil for my So Calif based boat.Temps being moderate, rarely 40's mostly 60F, what would the harm be in mixing 15/40 after only using 40 weight?I know on Aircraft we typically used straight weight oils but in more recent time, the advantage to multi weights not having to change with seasons convinced nearly all to use multi weights.Thanks for opinions.
    And the manuals are all explicitly clear on this: No multi-weights.
    Semper Siesta
    Robert Clarkson
    ASLAN, 1983 55C #343
    Charleston, SC

  4. #4

    Re: 40 weight oil for Detroit's

    Sounds like your mechanic is trying to get your engines to fail so he can rebuild them for you. Straight weight only.
    Looking for a 80 plus foot yacht
    Hatteras of Cheoy Lee

  5. #5

    Re: 40 weight oil for Detroit's

    Ron get their mechanics name so you don’t ever use them.
    SEVEN
    1979 53' MY Hull #563
    Antioch, California

  6. #6

    Re: 40 weight oil for Detroit's

    The answer is NO!!!

    No, No, NO!!!!!

    The oil needs to be rated for 2-stroke use. Most of the acceptable straight weights will say so.

    Never use multi-weight oils.
    Sky Cheney
    1985 53EDMY, Hull #CN759, "Rebecca"
    ELYC on White Lake--Montague, MI

  7. #7

    Re: 40 weight oil for Detroit's

    Delo 400 can be used in Detroit diesel 4 Stroke engines. In a DD 2 stroke engine (as was previously stated) you need to use a mono grade oil, 40 weight is the best and most common. The outside temperature will only make a difference if your in sub freezing weather. the next most important trait for oil in your two stroke is low sulfated ash, the manual states it needs to be less then 1 percent. I can not get Delo 100 where I live. So I use Mobil Delvac 1240 Which meets the requirement of a DD 2 stroke engine. (I buy it by the drum and it cost far less then 4 stroke oils) Good luck and happy boating
    Last edited by osprey; 12-11-2018 at 08:05 PM.

  8. #8

    Re: 40 weight oil for Detroit's

    Just to be clear there are two issues.

    Multi weight: two Cycle DDs need straight 40

    Delo 400: can’t be used (aince reformulated 15 years ago...) Need to use Delo 100 or other compatible oils (Delo 400 is not compatible )
    Pascal
    Miami, FL
    1970 53 MY #325 Cummins 6CTAs
    2014 26' gaff rigged sloop
    2007 Sandbarhopper 13
    12' Westphal Cat boat

  9. #9

    Re: 40 weight oil for Detroit's

    CF2 rated and low sulphate ash.

    Napa/valvoline is available almost anywhere in the us.
    Scott
    41C117 "Hattatude"
    Port Canaveral Florida.


    Marine Electronics and Electrical Products Distributor.

  10. #10

    Re: 40 weight oil for Detroit's

    What difference does
    low surface ash make

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts