I've read and re-read the coolant sections of my Cummins and Monaco owners manuals, and I must admit to being thoroughly confused regarding the type of coolant filter to use for replacement.
The Cummins manual says it depends on coolant capacity, deferring to the OEM (Monaco), but gives the following example:
Initial charge: Fleetguard WF2074, which is spec'd at 12 units of DCA4.
6,000 miles, 250 hours, or 3 months: Fleetguard WF2070, which is spec'd at 2 DCA4 units.
The Monaco manual also states it depends on coolant capacity, but doesn't specify the capacity. In the chart of filters and belts, it specifies use of the WF2071 coolant filter, which is spec'd at 4 units of DCA4, although my coach came with the WF2074 filter installed.
I stopped by a parts store before leaving on this trip, and all they stock is the WF2074 filter; They have no call for any of the others.
Yesterday, Ron Ruward checked my coolant using a test strip, and it fell clearly in the green zone on the chart, indicating that all three components of the test were within spec.
I'll call my Cummins dealer when I get home but, based on prior experience, I don't expect to get a sensible answer. I'll also try Monaco, but their owners manual clearly differs from the Cummins manual and from what was installed at the Monaco factory. ???