START USING FULL SYNTHETIC ENGINE OIL AFTER 400 HOURS..2004 B7800??

[Texasmark1]

No. Use 5-40 DIESEL oil with CI NOT SI rating. And you don't need all caps in the title line, it's considered shouting and totally unnecessary.

Rot 5w-40 is HD diesel rated. One of the best HD oils you can put in your engine. Ask Cummins. I did. And on the 400 hours, my change interval was 300 hours and they said on the first change interval.....aka at 300 hrs if you are sticky about it. They wanted you to leave the dino oil in for a time so that your engine could wear out some, getting all the new parts working together. I noticed DBY that on the B3.3 which I have, they have moved the change interval out to 500 hrs.

Mark

 

[Texasmark1]

Manual calls for 10-30 or 10-40 oil. Is it ok to use 5-40?

What is diesel oil with CI? Regular diesel motor oil-not full synthetic, or synthetic blend oils?
Any brand that you advise?

The lower the first number the better the cold start up lubrication. The lower the better. Case in point, pull a quart of Mobil 1 0w-30 off the shelf at WW and flip it over and read the comments on the back. Says it meets all GAS (Sx) warranty requirements that require a 5w or 10w-30 oil. I run it in my gas truck, change oil once a year and never add between changes; 2011 4.8 Chev V8. Great cold starts, and doesn't thin out when it gets hot.

Back to the previous post. Shell has been producing Rot T for eons for heavy equipment combustion rated engines (Cx), just as Chevron Delo and Mobil Delvac have been doing with their Cx rated oils. On the Rot full syn 5w-40 it also has a Sx (spark) rating. I suppose the others do too. I don't use them so I can't say.

Mark