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Filter change

Posted: Thu Aug 22, 2013 5:00 am
by offshoresnipe
When doing a filter change on Cat 3516's, does anyone else rotate the Aux. filter out and place that filter into the main filter housing along with two new ones, and then put a new filter into the Aux filter housing. I have been on vessels where we did not touch the Aux filters and only replaced the main filters with new. The theory behind this is the Aux filter is sitting in fuel or oil for who knows how long and getting gummed up and will not be as good as a filter that is only been sitting in the housing since the last change of the main filters.

I don't think I have ever been in the situation where we needed to switch over to the Aux. filters so not sure if this even matters.
Thanks for your input.

Re: Filter change

Posted: Sat Aug 24, 2013 3:11 pm
by D Winsor
We change both the main & auxiliary oil & fuel filters every time the oil is changed on our 3500 series Cats. It is not worth risking loosing an engine for the sake of a couple of filter cartridges that could be in questionable condition.
On many of the older Cats such as 398's & 399's there is a lever to switch to the auxiliary filters but I believe on the 3500 series engines the auxiliary filters automatically come into service if the differential pressure on the main filters exceeds a set value. The Instruction manual will confirm this automatic function