3406e fuel filter

Ultimately you want 2 micron, but running a 2 micron Davco and a 2 micron secondary makes no sense. The idea if a primary/secondary set up is to have a higher micron primary feeding the lower micron secondary to increase filter life. You will be fine with a 15 micron Davco and a 2 micron secondary. A 7 micron davco will work as well. It depends on how long the secondary lasts. Filters are generally changed with an oil change, if a secondary filter has no issues running that long, stay with a 15. If you find that the secondary plugs up too soon, use a 7 micron Davco.

 

Using too small micron will restrict fuel flow. Use whatever the factory suggests.

 

Guys,there's nothing that compares to a fleetguard fs1023,for fuel,and water separator filter,just my .02 though!

 

There is no restriction using the Davco even when it is totally covered it is less restrictive than any other filter. There is no need to use a secondary filter that is why there is the canister on the secondary mount.
Just a thought!

 

Typically, fleet trucks are set up with only a Davco, no secondary. It works well when you can control the fuel, like fleets with there own fuel islands. They generally run 2 micron Kaydon filters on their pumps, so if the fuel is filtered to 2 microns as the truck is being fueled and a 2 micron Davco lasts a long time. For most of us, we have no control over fuel filtration out of the pumps and have to deal with what we get sometimes. Running a higher micron Davco for a primary and a secondary 2 micron will make the filters last longer.

A Davco is a really good filter, but it's not magic. They can and do plug up to the point of too much restriction.

 

Yes a Davco will plug up, but it tells you it is plugged when the filter is fully covered it is time to change the filter, You are not changing a perfectly good filter, or running with a plugged filter, and not knowing it.