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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: rampeyboy on March 04, 2011, 06:41:30 PM

Title: how many fuel filters?
Post by: rampeyboy on March 04, 2011, 06:41:30 PM
Guys my Scenic only has one fuel filter mounted. Should I put another one inline? Does it have to be a special filter, ie primary/secondary, or can I choose any old mountable fuel filter that has sufficient flow? I was thinking about one of those nifty Davco 382(?) units...
Title: Re: how many fuel filters?
Post by: jackhartjr on March 04, 2011, 06:55:26 PM
Ours has the second fuel filter mounted on the firewall next to the radiator, in fact the main fuel line goes to it, then goes to the other fuel filter by way of a quick disconnect.  The second fuel filter is on the right side of the engine looking from rear to front.  A very nice man sent me the spin on mounts...I was supposed to send him and his bride some Scuppernong Wine from NC...I need to do that!
Jack
Title: Re: how many fuel filters?
Post by: gus on March 04, 2011, 07:37:43 PM
I know nothing about Scenics but other GMs have a primary filter before the engine fuel pump and a secondary filter after the fuel pump.

I wouldn't think one would be enough, just my opinion.
Title: Re: how many fuel filters?
Post by: Brassman on March 04, 2011, 07:39:52 PM
You're putting the two filters in series, right? The micron rating of the primary gets the bigger stuff, so your secondary lasts longer. The seconary's micron rating is a function of your engines injection equipment, and should be specified by the engine manufacturer. A filter before the pump functions more as a strainer, primarily to protect the fuel pump (and get the bigger stuff, and water [if so designed]).
Title: Re: how many fuel filters?
Post by: wal1809 on March 04, 2011, 09:00:13 PM
I am only guessing but on my Eagle the secondary would aid in catching debris if whenever the pump were to have a catastrophic failure.  If it were not in place after the pump then when the pump went bad so would all the injectors, the return fuel line and then debris all the way to the tank with the fuel return.
Title: Re: how many fuel filters?
Post by: rampeyboy on March 05, 2011, 04:39:24 AM
I have a fuel filter and mount that is laying in one of my bays. Probably not helping any! I'm sure it must have been removed for some reason. I'll fiddle with it and see if it is worth putting in, otherwise I will start shopping for a filter that allows easy maintenance. Thanks guys!
Title: Re: how many fuel filters?
Post by: TomC on March 05, 2011, 08:24:05 AM
On the DD engines from Detroit in the Freightliners, the normal fuel filter change is at 25,000 miles.  Add the Davco 482 (made specially for the DD engines) and the fuel filter change bumps out to 100,000 miles.  Plus with the Davco, there is no question when you need to change the filter.  Good Luck, TomC
Title: Re: how many fuel filters?
Post by: DaveG on March 05, 2011, 01:29:39 PM
The nice thing is that the old 2 stroke injectors aren't as fussy about micron rating as the electronic injectors are. Another interesting tidbit is that just about every application I see with the Davco...that is the only filter on them.
Title: Re: how many fuel filters?
Post by: TomC on March 05, 2011, 07:40:35 PM
DaveG is correct.  With our old 2 strokers, you can take both filters off and just use the Davco.  Or if you're like mine, take off the filter without the fuel pressure switch and keep the filter with the pressure switch and add the Davco-the filter with the pressure switch probably won't have to be changed again (at least for many years).  Good Luck, TomC