On 6/1/05 8:57 PM, "Loren Busch" <starwagen@GMAIL.COM> wrote:

> I see everyone referring to longer change intervals on the oil, but
> how about change interval on the filter?  I recall when the synth oils
> first came out that some sources suggested still changing filters on
> the same interval as dino oil.  Any comments?  What have the synth oil
> users been doing?
>
>

When I was running the aircooled engine in the mountains I was changing oil
monthly because I was toasting it.  Filter every two months.

With my water engines over the years I used synth or synth blend in all.
About 8 years ago Castrol did a test of synth in test stand engines where
one rack got its filters and oil changed at the standard OEM 3 month 3k
mile, another rack the 5k mile, and another rack set was run for 10k mile
with only filter change at 5k mile.

The end results were that on the bench they synth run for 10k miles was
found to still be in "spec" (meeting OEM minimums).  They also recommended
using a quality filter every 5k miles in the test report.  This last part is
what makes that report stick in my head because after I read the part about
filters I realized that in a picture I could see that the filters in use on
the engines were of different colors and probably brands.

End results were a recommendation of 7500 miles and six months for oil
changes.  Mobil has run similar tests and published the same data.
jimt