Correct engine oil

[Clydo]

My new to me 2003 engine owner manual states use 10 - 30 oil. Have
check around my area (San Jose, CA) and unable to find any. Appreciate
suggestions on right type to use. One boat store says 400 Dello best?
Universal Distributor said 10 - 40 or just 30 weight? Am firm believer in
preventive maintenance so would like to get right oil. Thanks for any
replies.

Clyde Thorington]
C310 # 245
ILEANTOO

 

[Calif. Ted]

Shell Rotella and Chevron Delos have traditionally been the most common and favored oils for diesel engines. I use the Delos because of it's widespread availability, while 10-30 may provide a little better lube at start-up, 30wt is OK in our mild climate.