How To: B5.5 FM100 5-micron Fuel Filter Upgrade

I plan on cleaning the head unit thoroughly before I put the final assembly in the car. The new filter should be acceptable in the new condition, correct? Why pull D2 into a new filter, take it out, throw it away and replace it with another new filter?

Unless I am missing something, making sure the head unit with fittings installed and new hoses, are thoroughly cleaned and blown dry before final assembly, they should be sufficiently clean enough for me to fill the new filter with DP prior to starting the car.

aja8888 said:

I plan on cleaning the head unit thoroughly before I put the final assembly in the car. The new filter should be acceptable in the new condition, correct? Why pull D2 into a new filter, take it out, throw it away and replace it with another new filter?

Unless I am missing something, making sure the head unit with fittings installed and new hoses, are thoroughly cleaned and blown dry before final assembly, they should be sufficiently clean enough for me to fill the new filter with DP prior to starting the car.

Click to expand...

if you feel like your cleaning is sufficient that's cool.

in mine, all parts and assembly were "clean" upon install, and i personally pulled a liter of fuel completely thru the system to further ensure any dust or assembly contaminants were flushed before connecting the line from the engine to the fuel-out fitting on the filter head. this step seems reasonable to me, but i appreciate if anyone feels this is unnecessary.

so, if it were my were my TDI, i would and did not use a can of Diesel Purge at the initial filter assembly and install. i would keep the can of Diesel Purge and use it when you change the filter the next time (a year or 20,000 miles from now).

hope this at least makes the procedure i used more clear.

cheers! rob

The start of my filter upgrade..

New parts:

Hose adapter fittings, plugs, Purolator filter, Marine rated fuel hose:




I expect the FM100 head and filter tomorrow from UPS. Then I will plan and start the upgrade. More pics to follow.

Tony

FWIW, I picked up some teflon tape rated for petroleum lines and other fuel lines at Lowe's. Granted, where I live, you can't go 10 blocks without seeing an oil derrick. Or so it seems...

keggo said:

FWIW, I picked up some teflon tape rated for petroleum lines and other fuel lines at Lowe's. Granted, where I live, you can't go 10 blocks without seeing an oil derrick. Or so it seems...

Click to expand...

Thanks, I was going to look into the pipe dope that was fuel resistant.

I know Bakersfield well having worked for ARCO and spent time at the Chevron/Texao producing fields up there. Lots of wells, mostly water and a little oil...

I feel sorry that you had the unfortunate experience of being in this dust hole. heh heh

This is a great thread BTW. Very informative! Thanks SUNRG!

Finally put in my upgraded filter!

This is the install of the 5 micron Stanadyne FM 100 unit with Quick-Release filter that SUNRG started this thread with. This is the recap of my install, which is a bit different than SUNRG's.

The first step is to obtain the FM 100 head unit, filter, fittings, fuel line, hose clamps and misc. nylon ties, and plastic hose covering. I also used a Purolater Pre-Filter to pick off big stuff and to provide a visual on the fuel. This is not a mandatory part.

Then cut off the mounting flange with a hack saw (10 minute job).



Once that is done you can paint the cut area black (looks nice). Then assemble the fittings blocking off two back ports. Use thread sealing tape as required.



Side view (shows painted area):



Next is to remove the old A4 style filter. At this point, we also ran a new feed line from the lift pump delivery plumbing against the firewall (see the plastic covered hose):



A picture of the unit assembled and ready to drop into the existing round filter clamp:



Run the new fuel delivery hose, connect the existing hose from filter head outlet to the injectors, use a 5/16" brass nipple to connect the two lengths of hose that were connected to the plastic thermostatic "tee" (return line to tank):



This is a side view of the completed assembly and installation. We filled the filter with diesel before installation. Use the lift pump to prime the system too. Check for leaks once started.



Finished, and now only very clean and highly filtered D2 enters my $600 each PD injectors. If you have any questions, please post them or PM me or SUNRG.

One thing to note is that when you go to change your filter, you do not need to disconnect any fuel lines as the filter is easily unlocked from the head and replaced with a twist. Priming can be done from the top cover removal, if you want.

Good luck!

Tony

After reading this thread I still don't have a good explanation in my mind about removing the T-port on the OEm style filter. Maybe I need an explanation of the four hoses:

-1 hose is fuel supply from the tank.
-1 hose is filtered fuel to the injector pump
-1 hose is extra fuel from after the injector pump that returns back to the OEM filter ??? or the tank through the T thingie
-1 hose is excess filtered fuel from the fuel filter that returns back to the tank???

So in removing the Tee all excess fuel returns back to the tank instead of having the opportunity to go back through the filter again? Why is the reason VW designed this is what is the reason everyone is OK eliminating this?

thanks

The tee is actually a thermostatically-controlled valve. At colder temperatures (9C or lower, iirc) the tee opens and allows return diesel to circulate back thru the filter rather than traveling all the way back to the tank. This helps the filter and fuel warm up and is designed to improve cold-weather operation, particularly where fuel gelling is an issue.

VW started this design in the early 1990s with the AAZ engine and it persists. Can it be safely removed? Probably depends on your climate and the quality of the fuel you can obtain in the winter.

Thanks for the explaination Vince. We don't have much of a problem with fuel gelling in our warm climate and most people use additives in cold climates.

Tony

Yeah, it's more of a "north of the Mason-Dixon line" kinda thing... probably not a worry in TX.

vw4life said:

After reading this thread I still don't have a good explanation in my mind about removing the T-port on the OEm style filter. ... So in removing the Tee all excess fuel returns back to the tank instead of having the opportunity to go back through the filter again? Why is the reason VW designed this is what is the reason everyone is OK eliminating this?

Click to expand...

some people were removing these Ts well before i got my first TDI in 2004 ... one of the vendors even had a slick custom replacement for the T fabricated and sold that IIRC was used with CAT filters.

it's not that the T is pointless, in theory it does work as Vince has described, and it can be removed in any climate provided the fuel is appropriately treated for the climate the TDI is operating in.

i've had mine in place for 4 winters with many near-zero and sub-zero days and have never had a problem. if you have any concerns regarding the Ts removal, when temps are forecast to get very low you can simply use winter diesel fuel additive and IME you'll have no problems.

aja8888 - nice job with the install!

SUNRG said:

aja8888 - nice job with the install!

Click to expand...

Thanks, I'll be showing it off at the GTG on the 9th. Thank you for the advice!

Late to the party -- and a question

Just discovered this thread, How I missed it before is a mystery!

2 quick questions:

1. Has anybody tried the filter head with the top-load heater option? Seems as if that would do the trick for us of us north of the Mason-Dixon line (even if only a short distance).

2. Why go the trouble of sawing off the mounting ears on the filter head. Do they get in the way on the BHW?

Here is a sugestion that you all might find beneficial. When using worm drive hose clamps on small hoses/fuel lines, wrap a couple turns of old fashioned friction cloth electrical tape around where the clamp will be to protect it. The French ship new small dia. hoses with the friction tape already on. It really makes a difference

I ordered all of the parts today. Grainger carries 3/8" NPT to 5/16" barb, so I got all of the miscellaneous fittings there.

Being just a tad concerned about losing the 'heated fuel recycle' option, I ordered the optional top-loaded heater as well. The only real change from the OP is that I elected to go with the smaller (4.3 inch) filter. I figure they are cheap enough I will replace every 20K miles anyway.

Simplified Installation

I just installed the FM100 in my 2005 Passat today.
I decided to simplify the process. I did not need any of the hose and I did not think the pre-filter was necessary. Return lines bypass the filter as in the standard installation, but the supply hose enters the filter on the opposite side and is shortened by about 1.5 inches...that's all!





This approach also did not require any re-routing of the hoses because is uses the stock hoses in the stock location. K.I.S.S.

CLARIFICATION: The stock hoses are in the stock hose ROUTING location. Obviously the hoses are not connected to the stock filter locations...the stock filter is gone!

ENCOURAGEMENT: This mod was one of the easiest I've ever attempted. And since the stock hoses are used with minimal alteration it would be straightforward to put the car back into its stock configuration.

Biodezl said:

I just installed the FM100 in my 2005 Passat today.
I decided to simplify the process. I did not need any of the hose and I did not think the pre-filter was necessary. Return lines bypass the filter as in the standard installation, but the supply hose enters the filter on the opposite side and is shortened by about 1.5 inches...that's all!

This approach also did not require any re-routing of the hoses because is uses the stock hoses in the stock location. K.I.S.S.

Click to expand...

Very nice! I had followed Sunrg's older instructions. Goes to show you that I have no imagination! Yes, it is simple and the little clear pre-filter is not needed. After 40K miles on my setup, the little filter is still clear and clean. But I think I will take it out and chuck it....

Why not to swap the 'said bad' B5 fuel filter with A5 style two hole stock filter?

Great timing! My parts just arrived and I will be cloning the Biodezl plan B.

Thanks

I had an old stock filter still so I swapped it out on Friday. 136K on the original filter. Yuk! After swapping out to the new one I think I noticed a little more 'pep' out of the motor. Maybe it's just mental...

Next time I will do the filter upgrade.

Is it a drop-in style by removing that upper knurled lid? Does anyone have a pic of the filter disassembled?

Michael Slade said:

Is it a drop-in style by removing that upper knurled lid? Does anyone have a pic of the filter disassembled?

Click to expand...

Inserts into head from underneath and is locked in with locking ring. One twist loose, one twist lock.

Go to thedieselstore.com and seach PART #: 31877 for a look at the filter.

or: http://www.thedieselstore.com/template/productOutput.php?&partNum=STA31877&VehNum=

Michael Slade said:

Is it a drop-in style by removing that upper knurled lid? Does anyone have a pic of the filter disassembled?

Click to expand...

I think you were asking how the FM100 works, right?

The FM100 filter element is released from the FM100 upper unit by rotating the black plastic ring underneath the upper unit 1/8th turn counter-clockwise. The top knurled part is left alone. After the upper unit is moved out of the way, the 5mm (or is it 6mm) torx screw on the clamp is loosened to allow lifting the filter body out of the stock filter holder assembly. The black ring that comes with the FM100 unit slides off the bottom of the filter. When installed it fits over the upper "lip" on the filter to make a snug fit with the upper FM100 unit.

There is one limitation of my simplified installation. To replace the filter element I probably have to remove one of the fuel hoses from the upper unit. In the original configuration it appears that the upper unit can be flipped out of the way with the hoses attached to allow the filter element to be removed. I figured this is going to happen so infrequently (at most 5 times over the life of the vehicle) that this was not a big deal whatsoever.

Yes, that is exactly what I was asking. Thanks.

BTW, it's NOT a torx screw, it is a 12-point triple-square. I replaced mine with a good ol' fashioned six-sided bolt. Much easier now with the speed wrench.

What do you think about using this inline for easy disconnection?

http://www.amazon.com/Single-Shut-Off-Connector-Coupler-Buna-N/dp/B0015HQ6V4

daedalus said:

What do you think about using this inline for easy disconnection?

http://www.amazon.com/Single-Shut-Off-Connector-Coupler-Buna-N/dp/B0015HQ6V4

Click to expand...

Shut off style quick disconnects have tons of restrictions - I don't know how much is too much.
Also, you would have to check the chemical compatibility of the seals(Buna) with diesel fuel.
If you want good disconnects, you'll likely have to look elsewhere and pay much more. I use some from MSC on some machines at work, they are called "snap-tite". Again, I'm not sure what the restrictions are and chemical compatibility.

Jon

What if you extended the fuel lines approx. six inches on either side of the fuel line so that there was enough slack to pull the filter out of the retaining ring? I like the idea of being able to not disconnect the fuel lines when changing the filter.

Better yet, I like the idea of having a drop-in style filter like the oil filter is. Has anyone found something like that yet?

With my extended supply line, all I have to do to change the filter is loosen the clamp, lift out the filter and head (hoses attached), turn the lock ring, remove the old filter, slip in a new one, drop it all back in the clamp and tighten the bolt.

No disconnecting a hose. Takes all of a few minutes.

Perfect.

aja8888 said:

With my extended supply line, all I have to do to change the filter is loosen the clamp, lift out the filter and head (hoses attached), turn the lock ring, remove the old filter, slip in a new one, drop it all back in the clamp and tighten the bolt.

No disconnecting a hose. Takes all of a few minutes.

Click to expand...

If I understand correctly -- you did not extend the original hoses at all; just used opposing sides of the filter head ports and there is enough slack to raise the filter high enough? If so, that is the clear winner.