Years back my dad had a Ford 7.3 PS. He got a bad load of fuel once and the truck was never right after that. Since this is my first diesel, and I want to avoid those kinds of problems, I have been considering adding a fuel filter/water separator system and later an oil filter system to my truck, but there are a few things I'm fuzzy on. Hoping I can get them cleared up. Most of the threads seem to be written by and for folks that have a pretty ample knowledge about diesels. I don't. Please use a lot of small words and some pictures. Thanks.

1) I read that Bosch recommends 2mic filtering for their injectors, but Dodge's filter is 7mic. Airdog II's spec sheet indicates 5 micron. I have read at least one thread that talks about installing the airdog and keeping the stock filter for additional water separation. Question in my mind is this: Isn't there a 2 micron filter element I can buy for the stock Dodge housing? Does Airdog have a 2 micron element to replace the 5 micron unit?

2) I have seen some threads indicate they built their own fuel preparator system. Do you recommend adding the new system between the stock filter and the injector pump, so as to get a pre-filter effect from the stock unit before the 2 mic filter/water separator unit?

3) If I add a 2mic fuel filter/water separator unit to the stock unit, will I need to also install an accessory lift pump or will the stock pump provide sufficient fuel pressure for the two filters.

4) Would somebody walk me through a summary of an installation of a 2 micron system, i.e. what is needed, where is best to mount it, how it gets plumbed into the existing system, and maybe some recommendations for systems.

Just for starters, I have an 05, so the lift pump is in the tank and seems fine.
The truck will not be used for "pulling", but will be used for towing. No high performance build, other than a BD Triple Dog.

 

I installed two additional filters, one before and one after the stock filter unit with a hleper pump as shown in the pictures linked below. The additional pump is not needed. It is currently wired to activate via the water/meth hobbes switch to provide additional flow under high load. Prior to that is was simply installed as a backup pump in case the stocker failed, but the stock in-tank pump always maintained at least 5psi post filter, even running a Smarty Jr. at SW2. The stock pump typically holds around 9psi pushing through all three filters under normal driving conditions all by itself.

http://stuff.is-a-geek.net/PhotoAlbu...ics/CRD_32.JPG
http://stuff.is-a-geek.net/PhotoAlbu...ics/CRD_28.JPG
http://stuff.is-a-geek.net/PhotoAlbu...ics/CRD_26.JPG

You can get the necessary fittings and line to plumb around the stock filter and into the CP3 from a Glacier Diesel big line kit.

 

i used about ten different variations until i found what i think is the best. and is inexpensive, the filters are used on huge numbers of larger engines and because of this are cheaper than the stock one. i will give you napa # but can cross reference to any other. get two 4770 bases, a 3604 w/s 8 micron filter and a 3406 2 micron filter. connect the two bases together using a 1 1/2" long nipple install a 3/8" hose barb on each end. get a piece of 2"x2" angle about 8-10 inches long. mount the bases to the angle. in front of the fuel tank there are two bolt holes for a short seat option some of my trucks has bolts in them some do not, but mount the angle to this point.next cut the fuel line into at the point beside the filters. connect a piece of 3/8" hose over the line from the tank and to the 3604 side of filter. next the line to the engine to the 3406. most people now remove the stock filter cartridge, i do not. i replace it with a 10 micron 3585 as an insurance policy. connect a fuel pressure gage up to the cp3 using a tapped banjo bolt, oil pressure gage installation kit and a small cheap 15 psi gage. you will have about 7 psi do not change the filters until the pressure drops to about 2 psi under load. the dirtier a filter gets the better it filters. the total time for the filter install is about three hours on the first one i did the next ones about one hour. the gage install about 20 minutes and $40 if new gage. when you get ready for the oil bypass pm me you need to get rid of the in cylinder egr first. one more thing the stock filter will now never have to be replaced and the new filters will last a very long time.

 

It's generally best to arrange the filters with finer ratings further downstream. A single additional 2um filter right before the CP3 is more than adequate for most applications. The only reason I added a filter back on the frame was because I was already planning on tapping in there for the pump so another filter was no big deal. My filters go 14 >> 7(stock) >> 2. I figure I will change the primary 14um filter most frequently or if I pick up a bad load of fuel somewhere. It makes for an easy spin-on fix on the side of the road, should that unfortunate occurrence ever arise. After being installed for 16 months with this particular set of filters I see no change in fuel pressure. Haven't got any water out of anything since right after I bought the truck over two years ago and drained/changed the stocker.

 

Great responses. Thanks much. Questions for both of you:

Ace: The first pic is of the 2mic filter, after the stock filter. It shows a fuel line, which appears to be a 3/8" line, on top of the housing. Does that go to the pressure gauge? Seems large for a pressure gauge, but I can't think of anything else it would be for. I also noticed your 14 mic filter is in line upstream from your accessory fuel pump. Is there a reason for that, other than ease of installation, or does it matter where that pump is located in relation to the filters?

Carl: You indicate you replace stock filter element with a 10 micron element and leave it after (downstream from) the 8 and 2 micron filters for "added insurance." The only sense I can see in that would be in case of failure of the other filters, or possibly a need to bypass the finer upstream filters. Is there much chance of that? It seems to me that leaving the stock filter would just create an additional load on the lift pump that doesn't need to be there. Maybe there is something I'm missing?

Both: Do the filters also act as water separators or is there a separate trap for water?

I haven't located one, but is there a 2mic filter available for the stock housing? Just for neatness and ease, I would think the "cat's meow" would be a setup like Carl's, except with 10 and 5 mic filter elements, and then a 2 mic filter element in the stock housing. Can that be done?

One more: I noticed some commercial units show a heating element, either electrical, coolant source, or both, in the filter housing. Is that necessary, useful, or just nice to have. Does it make a difference with biodiesel or a biodiesel mix?

 

i agree the stock filter does not need to be there in cutting the line and installing the filters i would leave the stock filter in for a day just to klean any trash out. the 3604 filter is a 8 micron water separator with a drain. i get my fuel from bulk tanks at our yard or from truck stops both have 10 micron filters on the pumps. therefore the 14 micron filter is not useful to me. i just noticed i made a mistake in the 2 micron filter # it should have been 3528 the 3406 is aces 14 micron w/s filter #. there is no 2 micron filter for the stock housing and it would not hold enough dirt if you could find one. the 2 micron filter catches a huge amount of dirt that just passes through the 10 micron filter. i was really suprised when i pluged my first one and cut it open and seen how it was loaded up.

 

OK, that helps. Just to make sure I understand, the 3604 is an 8 micron filter AND water separator, while the 3528 is a 2mic filter. I would install both side-by-side, with the 2mic on the downstream side. Now a block-off plate to replace the stock filter runs about $40. If I leave the stock filter in place and install the setup like you are talking about upstream, will the stock filter affect fuel pressure enough to be a problem (remembering that my truck will not be used for any extreme performance stuff)? If not, I can see just leaving the stock one in place, if for no other reason than to save the $40 for the block-off plate.

Now, as for the pressure gauge, does NAPA also carry the fuel pressure gauge and oil pressure gauge kit you are talking about? I take it you mounted the gauge in the cab?

Is there any real issue about filtration of air from the fuel, or is that an Airdog sales pitch? It would seem to me that a 2mic filter would handle any air in the fuel, but then without some sort of backflow to the tank, where does the air go?

 

Yes, it is a 1/4" i.d. grease gun hose that goes to a needle valve near the firewall and a stainless braided hose goes from there into the cab and gauge. Works quite well for that purpose.
Actually, it's downstream: Pump >> 14 >> 7 >> 2 It depends on the filter. Some are designed specifically to be pushed or pulled through and some can go both ways. I chose that particular install arrangement based on ease of access and space available to work with on the frame rail as well the unused mounting bracket Mopar had provided.
The primary and stock filters in my sytem are water seperators, the 2um secondary is not.
To my knowledge, there is no 2um cartrige available for the stock cannister. My reasoning for retaining the stock filter is it's there, works just fine for what it is and has a WIF sensor and heater built in already integrated with the truck's electronics, so makes no sense not to use it. Like I said before, all you really need is a 2um after the stocker to be all set for a clean, simple install. Whether or not you need the heater depends on where you live. It could be the difference between making it to your destination or not in really cold weather.

 

IMHO the air in fuel is a sale pitch...we have self bleeding systems anyways. I would love to find one air/fuel mixture related injector failure. Air is much lighter than diesel and thanks to bouncy will not stay suspended in the diesel. Now I am going against conventional wisdom and run a 10 micron ws, a 2 micron fuel filter and then the 7 micron stock (sometimes the 5 micron PF7977). The reason for this are:

The spin on filter have a much longer service life than than my stock filter so it will take a while for them to plug. You can add a WS on the rail, run it to the stock filter and then run the GDP kit pre-cp3.

I have engine mounted APPS

I am a lazy SOB

This is what I did:

My set up:







Build thread:

http://www.cumminsforum.com/forum/3r...er-set-up.html

 

you do not need to do anything if you just take the stock filter out. but just remember the canister held all of the dirt that did not attach to the filter and you must throughly clean it. i am also lazy and it is a lot easier to stick a 10 micron one back in. i have 15 psi gage's in all of my trucks the 10 micron stock filter sees no visible change in pressure. and as stated the air is bs. napa or any other parts place has the kit the gage i get from every where ww granger has them for about $10 winnelson ferguson nelson nun surplus center home depot and lows have thim for about the same price. the expensive ones are for looks only. we have been using the cheap ones for 43 years now with no problems. some like the vp44 need glycerine filled gage or a snubber added to minimize gage shake.

 

On a common rail I would not run a 10 micron fuel filter...the stocker since 2004 has been 7 microns. Really you need at least 5 microns on these applications.