With regular (open end up) filters, I always fill mine but I try and put
all the oil down the OUTSIDE of the filter, through the small holes so
it does get filtered first. BTW... pushing air through an oiled filter
is not an issue... it has the pressure of the oil behind it and it will
find it just as easy to make it through a wet filter as a dry one.

Also remember.... most engine manufactures don't want their engines to
go to 5000 hours + in the marine environment without another donation to
their profitability....

Ian Malcolm wrote:
wrote:

I just went to a class last week by the local Catapiller distributer.
Even though the filters are mounted such that you can fill them they
recomend that you leave them dry. They apparently do not want oil, even

brand new oil, entering the engine without passing through the filters
first. If you prefill the filters the oil in the filters goes directly
into the engine without being filtered, they consider this to be a bad
thing.


************

That's pretty surprising.

I would think that running the engine for a while without oil pressure
would almost automatically do more damage than running a quart of
virgin, but unfiltered, oil through the engine. I guess the Cat guys
probably know 1000 times more about diesels than I do, though.

Consider what happens to any air in the line from the oil pump (and most
pumps will drain back down some) Air goes through dry filter paper just
fine but will it go through heavily oiled filter paper? I can imagine a
scenario where you get LESS oil during first startup with a filled filter.