Weekly generator test today and I was there to check it at startup and during cool down cycle.
Just wondering. Would there be any benefit to switching to a T6 5w-40 full synthetic? It値l get serviced before next flock. As I refuse to service it with birds in barns. As soon as I dropped the oil the power would go out with my luck.
Great maintenance '09, as always.
For low hour changeouts like you do annually, I'd probably just stay with the T4. Cost no object, the T6 will give
you slightly better flowability at startup, but in your application I'd say the difference is minimal.
I am a fan of T6, but I deal with much lower temperatures than you, and I really like T6 for low temps. The other potential T6 gain is longer OCI, but I don't expect you want to go past 1 year in your application.
I'm partial to synthetics in turbo applications, but that's partly me/my age showing..... conventional oil today is many times better in this regard than when I was a pup.
You do a cool-down after running.... can't see a problem with T4, unless all those OTR truckers just got lucky with the billions of miles they went with Rot 15W40

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'Ol Murphy does get around..... hear 'ya about the bird/timing thing......
(Edit - not sure what your Cummins hour limit is on oil, but T6 may give you a bit more peace of mind in an extended outage, as in multiple weeks of running nonstop. Depending on your grid, that may only happen once in 2 or 3 lifetimes.....).
Rgds, D.