Posted by Jim Chance on Sunday, November 14, 2004 at 4:18PM :
In Reply to: Speaking of oil type/wt. to use ? posted by RDavis on Sunday, November 14, 2004 at 2:28PM :
I think extend drain interval oils only make sense for big industrial engines. Going to extended drain intervals is a gamble unless you have oil samples analyzed every few hundred hours. This makes sense if the sump holds a few drums of oil. If it only holds a few quarts it is easier and cheaper to change it.
I use to run a maintenance program for a fleet of small ships. They were mostly DEtroits but there were some Cats and EMDS. Here is what I learned:
1. The manufacturers schedule is conservative. You can usually get more time on oil. About 1 time out of 25 you need to go by the manufacturer's schedule. If you don't catch that 1 time you can really tear some stuff up. If you don't change it you have to monitor it.
2. Lots of oil is ruined by fuel dilution. Most is due to internal leaks and other problems that can be fixed.
3. Oil does go bad and some goes bad faster than others. CD oil would last me almost twice as long as CC.
4. After fuel dilution issues are fixed the thing that matters most is oil leaks. On engines that leak alot you can go forever without an oil change.
JIm Chance