T1N and NCV3 Fuel Pre-filter

Aqua Puttana

Poly - Thread Finder
For those who are concerned that the OEM filtering is inadequate and want to improve their chances of riding through off-grade fuel.

Here is an interesting read on duramax issues. Fuel velocity and filter size/capacity plays an important role. Just because a filter still passes enough fuel doesn't mean it is usable? The stock filter is likely cellulose media type, and is fairly small. I don't see any disadvantage to adding a ~120gph pre filter? Donaldson offers a synthetic media water separator which is supposedly more affective than plain cellulose. :idunno:

Above, the author indicates that a pre-filter helps to address many problems.

DMax Store Article said:
That leads us to the reason the pre-filter solved the problem. Suddenly the main filter had a much more manageable task: all it had to do was catch the small fraction of larger particles that made it through the pre-filter. The percentage of water and other contaminants making it through to the injectors dropped dramatically. The presence of a good pre-filter along with proper maintenance in keeping with the main filter service intervals generally allowed the early Duramax injectors to run quite happily.

Thanks for the information. Very interesting.

Does the OEM Sprinter filter suffer the same inadequacies as the Duramax? Are the Sprinter filters as poorly sized? A 3.0 L engine uses less fuel overall. I assume that the Sprinter filters are a different manufacturer.

The way I interpret the information that was communicated, there may be great benefit and the best bang for your buck by just adding a pre-filter and keeping the OEM Sprinter filter in service. Maybe an entire fuel filter system change isn't really cost effective.

The article has me re-thinking the value of procrastinating on... I mean, extending my fuel filter change intervals too long.

Adding or replacing with an entire fuel filter system can be expensive.

Maybe simplicity, add another factory filter twice the chance of catching foreign stuff maybe change that on at half the recommended intervals suggested.I also emailed raycore to pick their brains,waiting for reply.
I like that idea, but I believe that the NCV3 OEM fuel filter is quite expensive.

This T1N OEM filter choice is less expensive and doesn't have the Water In Fuel sensor port to deal with. There is a one time cost of the OEM plug in piece for the connection. Use a MAHLE KL 313 filter.

THE FIX I Installed a fuel filter design from Europe for European Sprinters without the water sensor on the bottom and no water drain valve. No Leaks, no air, no stalls, starts everytime !
I never saw a great engineering design in a fuel filter with 7 connections to possibly leak, it should have an in and an out. The fix has 5 connections that still could leak, but fixed my van
The filter is only available in North America on-line, mine came from eBay for $30.
Since my fuel filter has never had water in it when drained, and the WIF light never came on, I think I will be fine without a drain (LEAK) hole. The Top connections are a perfect fit.

Part Numbers :MB # 6110920201, or 6110920601, or 6110900852, or 6120920001,
Fram P9436
Mahle KL100/1 or /2
Bosch 0450905930
MANN WK842-13 OR -17
Hengst H70WK11 or H70WK18
WIX WF8239
Baldwin BF7756

My suggestion. = Use a MAHLE KL 313 filter.

Add the T1N pre-filter and change that on whatever filter change schedule which you feel adequate. Don't change the more expensive OEM NCV3 filter until necessary, or until you just can't bear to have it in service any longer.

No worries as to flow rates, proper pressure rating, compatibility, etc. The original existing OEM filter has the WIF sensor. No real need to duplicate that.

My concept for installation would be to snuggle or hang the added filter unit in the area above the OEM filter. I'm quite certain that there is room in the T1N engine bay. I have no idea for the room in the NCV3.
I have no data.


IGNORE FROM HERE DOWN. Go to post #4. Use the MAHLE KL 313 filter.


The plug in part needed:
The part is called the "preheater valve" and is part # A6110780249

This may also be needed:
The part # for the fuel line is A6120700532 and list price is $18.50.

The water sensor goes in whichever way the receptacle for the plug will point towards the rear of the vehicle so that the plug will reach.

The part that you broke is called the "preheater valve" and is part # A6110780249 and is reasonably list priced at $14.00. It is part of the fuel return system from the fuel rail and injectors and either diverts fuel into the tank for cooling or into the filter if the fuel is cool.

I don't think you can run the truck without it because you will be leaking fuel. You could conceivably tie the two hoses together and plug the inlet on the filter to prevent leakage but check on the part availability before you start cobbling things together.

On the issue of breaking the clip hold down for the fuel line, you are pulling fuel through that hose to the pump on the front of the motor. Some tie wraps might hold it down.

The part # for the fuel line is A6120700532 and list price is $18.50. These prices came from Boston Freightliner in Everett, MA and are current as of 2/3/2012.

Good luck and be careful next time you change the filter. I have yet to find a good tool to remove the fuel line connections. The white clip has to be pushed in when removing or installing and do not leave the white clip pushed in for a long period of time because it will distort the ring that holds it down. I have used a pair of curved needle nose pliers on the exposed black part of the fuel line from the top, gently rocking back and forth until it pops free. I believe that a quick spray of some lubricant on the fitting might make removal easier.
Perhaps Bruce can verify that I show the proper parts info. He's definitely one of our parts gurus.
Dodge 05080460AA

Note: So far I have not been able to verify the working pressure rating of the OEM plug in part and fuel hose. That could be a deal breaker for the OM647 and OM642 engines with in tank fuel pump. (Added: The filter itself is good to go.)


The Mahle KL 100/2 filter is listed for the OM647 engine. So ok for in tank pump.

Use a MAHLE KL 313 filter.

Lots of other OM647 parts too.
Last edited:

Aqua Puttana

Poly - Thread Finder
FWIW, Jon Caples (jdcaples) added a prefilter to his 2007 & documented it here:


The entire reason for my pre-filter suggestion here is to apply the KISS formula. It's probably not as good at protecting the engine as a more complex and expensive solution like both Jon Caples and Jon Talkinghorse43 installed, BUT this solution uses OEM type filter components and, per the author in the article above, should be effective at reducing risk.

Whether the next step up to a more complex and expensive DIY designed/spec'd out filter system is worthwhile is up to the individual to decide.
(Personally, at this time, my choice is to not install anything extra in my system. That is for my T1N. The fuel filter system for that engine so far has seemed adequate unless a Water In Fuel warning isn't properly addressed right away.)

Last edited:

Aqua Puttana

Poly - Thread Finder
THE PERFECT SOLUTION for a OEM style pre-filter.

No seals. No special OEM fitting. No muss. No fuss. Just an in and out hose connection.


Listed for Mercedes 3.0 V6 Diesel.
In Europe and Australia, the Chrysler 300C was available with a Mercedes-Benz 3.0 L diesel V6

This is what I recommend for a Sprinter pre-filter. Cheap and effective.




Added May 2018.
Recently mentioned by Desertadventures. :thumbup:
Link to filter vic recommended *When purchased though this link it helps Sprinter Forum.

*Currently it's also less expensive here on Amazon than eBay. :cheers:
If the links go stale search using MAHLE KL 313

Hose Barb Union Connectors are needed to connect. The size is 5/16" x 1/4". (10 mm x 8 mm) and 1/4 x 1/4.

CJPJ is correct that only one 1/4 x 5/16 hose barb fitting is needed on the outlet side. The inlet needs a 1/4 x 1/4 hose barb. Brass is fine for diesel fuel service.

Here's some part numbers and possible suppliers. The 1/4 x 5/16 fitting is not very common. Turns out a local fish pond supply store may stock the fittings.


1/4" x 5/16" Brass Hose Mender
Retail Price: $3.52
Our Price: $1.76
You Save: 50 %
19 in stock.
Item Number: FIT-031
Manufacturer: Brass Fittings
Manufacturer Part No: UNB-5-4

1/4" Brass Hose Mender
Retail Price: $2.52
Our Price: $1.26
You Save: 50 %
44 in stock.
Item Number: FIT-030
Manufacturer: Brass Fittings
Manufacturer Part No: UNB-4

TH43 Jon reminded me that a 3/8" hose will work on the 10 mm outlet. A 1/4" x 3/8" hose barb connector set may be easier to source than a 1/4" x 5/16".

MettleAir 129-6-4 3/8" ID x 1/4" ID Reducer Barb Mender/Splicer/Joiner/Union Fitting Brass Tubing Hose Adapter/Coupler

A pipe coupling with proper sealant can work with hose barbs. Or a female pipe to male pipe barb combination.

Harbor Freight can supply all the fittings needed.

Combine this:

1/4 in. Standard Air Hose Repair Kit 7 Pc
(Don't use the included Harbor Freight worm drive hose clamp on your Sprinters.)

With this:

1/4 In. X 3/8 In. Barbed Fitting With Clamp

And this:

1/4 in. x 1/4 in. Female Brass Pipe Coupling


Some other possible filter part numbers (verify).

FRAM P9635
MERCEDES 646.092.00.01
MERCEDES 646.092.03.01
MERCEDES 646.092.05.01
Baldwin BF9846,
Donaldson P550808, Hastings FF1187,
Purolator F56303
Last edited:

Aqua Puttana

Poly - Thread Finder
Added info.
I'm no expert.

According to the DMax article author, a pre-filter does help the existing water separation capability to do the job.
The Mahle Pre-filter concept.

According to the DMax author a pre-filter helps.

The initial cost for the Mahle filter, connecting hose, clamps, and 2 each hose unions will likely be under $40.00 total.

The filter can be supported with a bracket formed by perforated strap or other metal. The filter can be clamped to the bracket using a worm drive hose clamp. There is room in my OM647 engine bay.

My service schedule.

Initially change out the existing OEM fuel filter [to a Mahle KL228/2D] and plumb in the new KL313 pre-filter at the same time. After the pre-filter is in service then change that on whatever service schedule that the owner feels appropriate. Leave the original OEM filter alone.

The Mahle filter is about $25.00 per change. In the TIN the filter will be up where accessible. It will only require R&R of 2 each hoses for the change. The cost avoidance of not needing to change the more expensive OEM WIF filter will pay for the pre-filter.

On the OM612 engine just changing the added pre-filter means that the problematic air leak filter system is disturbed less often. Remember, 2 hoses for the pre-filter.

Gelling in the Mahle pre-filter. There is more risk of gelling with any added pre-filter. What cheaper added aftermarket filter system will have fuel pre-heat built in? I believe that I can safely answer "None".

I'm actually considering adding the pre-filter to my 2006. I hate the access to the fuel filter now. Having a fuel filter accessible and only needing to deal with 2 hose connections is attractive.

A self designed aftermarket filter may be more effective (or maybe not...), but it is expensive and not easily installed.

I see no serious drawbacks to installing a Mahle pre-filter. I actually believe that there is benefit.

:cheers: vic
Some information on one method of emptying the fuel tank if, God forbid, you ever get the dreaded WIF dash warning.

With gasoline contamination a bit of heel left in the tank is not a serious issue. Of course if there is water present then the idea is to empty the tank to make it lighter for tank removal and then proper cleaning.


Some discussion about operator response to a WIF warning is here.

Water in Fuel Light WIF warning is on.


Last edited:

Aqua Puttana

Poly - Thread Finder
I contacted Mahle customer service for some information about the Mahle KL 313 filter. This is the repsonse.

Mahle said:
Hello Victor

Thank you for choosing MAHLE Original filters for your filtration requirements

What is the micron rating? 4 micron

Is the filter designed to trap a reasonable amount of water? If yes, what is the
technology? This filter does not have a water separation system built in.
Kind regards,

MAHLE Aftermarket Inc.
Product Application Coordinator (Data Management)

Mahle also had some comments on their web page for diesel pre-filters.

This information would apply generally to our OEM fuel filter with WIF.
Mahle Filters said:
Function of MAHLE diesel fuel filters

In order to prevent paraffin separation and clogging of the filter at low ambient temperatures, pre-warming with electric heating elements or recirculation of fuel that has been warmed by the engine is used in our fuel filters.

For newer generations with even higher requirements, MAHLE has opted for two separate filter stages during water separation.

The first filter phase consists of a cellulose filter medium with an untreated melt-blown contact surface for increasing the contaminant absorption capacity. This melt-blown contact surface optimally causes the many small droplets to coalesce into larger ones. The particulate filter in the shape of a pleated star even agglomerates the finest water droplets.

The second filter phase consists of a water separator, whose hydrophobic fabric with a mesh width of 25 µm divides the barely stable emulsion, thus separating the water. As this occurs on the clean side of the filter, it is referred to as clean-side water separation.
The low temperature information is interesting. The electric heater referred to below describes the PTC heater they have in some products.

Mahle Filters said:
The problem of paraffin separation is well-known: at temperatures below zero centigrade, paraffin crystals are formed in the diesel fuel—the fuel converts into gel and flocculates. The flocculate is carried to the fuel filter, where it clogs its surface and blocks the filter. The fuel can no longer flow to the injection pump, the engine is no longer supplied … and stops running.

There are indeed modern diesel fuels for winter use that are cold-resistant; for instance, the winter diesel available in Germany remains liquid down to about -23 °C [-9.4 F] thanks to special additives. However, to assure vehicle operation also at extremely low temperatures, fuel filters with heating elements are increasingly used. PTC heating elements are the safe and modern solution for fuel heating. The abbreviation PTC stands for “Positive Temperature Coefficient”. These have the characteristic that the electric resistance of the heating element increases with rising temperature. As the current decreases disproportional when a set temperature limit is reached, there is no danger of overheating. This makes heating units with PTC elements especially safe.
Some information specific to in-line pre-filters.

Mahle Filters said:
Inline fuel filters: Heat for diesels

Fuel preheating—the effective solution against paraffin separation

Experienced diesel drivers are familiar with the problem: when the temperature falls below zero, the vehicle is in danger of stopping. This is due to the tendency of the light oil used as fuel to form wax-like paraffin from -7 °C and below. The fuel takes on a gelatine-like consistency and flakes form. These flakes float towards the filter and clog its microporous surface. It may only take a short time until the fuel supply to the injection pump is interrupted. The result: the engine looses power—and then it stops; an annoying state of affairs.

Much has been done meanwhile to avoid this dilemma. First there is the 'insider tip' of mixing petrol into the diesel fuel. However, this can only be accepted in absolute emergencies, as the added petrol lowers the Centan number, which is essential for the ignition quality and thus for cold starting. Moreover, some diesel engines will not tolerate such mixtures. A widespread solution was the use of additives that could be added by the driver. However, it was necessary to add these already before the onset of the cold. Moreover, this runs the risk that the additives could affect performance and service life of the engines.

Nowadays, the oil companies are responding to this problem and sell so-called 'winter diesel' during the period from early November until the end of February. This diesel remains liquid down to -20 [-4F] or -22 °C [-7.6 F]. However, if the temperatures drop even lower or if wind chill takes effect, trouble is still looming.

The optimum solution: A heat source for the diesel

<The electric heater product information is snipped.>

The T1N OEM diesel filter system uses re-circulated fuel from the engine to warm the fuel filter. The fuel heating only takes place after starting. That means that the OEM fuel filter is always at ambient temperature after sitting overnight. Some NCV3 model engines may have electric pre-heating.

My use of Power Service Diesel Kleen with anti-gel for winter service is my answer to avoid gelling as opposed to installing a heated pre-filter. That has been working for me for 7 winter seasons now. Those operating further north than I do may need to apply different methods.

The Mahle DL 313 filter will provide 4 micron filtration with no water separation or pre-heating.

What is in the posts above is enough information for me to install a Mahle DL 313 or equivalent as a pre-filter. Should it ever be necessary, the pre-filter can easily be removed from service by using the 1/4" hose joiner to connect the fuel inlet/outlet hoses and by-pass the pre-filter.

Do with this information what you wish.


Aqua Puttana

Poly - Thread Finder
Added information for those who have nothing better to do.

mydmax said:
Doing something to aid filtering is better than nothing.

Cummins has a filtration division which was created in 1958. That gives them reason to put out a bit more info on the subject than a filter customer like Mercedes might provide.

Cummins Filtration said:
Fuel Filtration FACT SHEET

The Importance of Fuel Filtration

Whilst diesel fuel is the engine’s energy source, it also performs several other key roles:
■ Cooling – by circulating through the injection system and absorbing unwanted heat
■ Lubrication – by separating the moving components in the fuel feed and injection pumps
■ Cleansing – by transferring contaminants to the Fuel Filter(s), where they are removed.

Fuel contamination - the biggest enemy

The enemies of diesel fuel are:

■ Dirt and sediment – when present in the fuel system, they will result in blockage of the filter and increased wear within the fuel system.
■ Water – is the greatest concern because it is the most common. It can be introduced into the fuel during the refueling process: through condensation inside the fuel storage tank, or due to poor house-keeping practices. The effects of water in diesel fuel can be serious, causing injector tips to blow off, corrosion and reduced fuel lubricity, resulting in premature wear to pumps and injectors.
■ Organic contaminants – Asphaltines and paraffin wax, which are residual components from the refining process, will block screens, strainers, filters and even hoses.

Advanced Fuel Management Systems

To meet today’s stringent emission regulations, fuel system injection pressures are extremely high to achieve better and cleaner combustion. As a consequence, clearances between the moving parts and the higher number of very small nozzle holes found in injectors all need improved protection from erosion. 50% of the worldwide diesel fuel supply does not meet OEM specifi cations for cleanliness; particles greater than 4 microns in size are known to cause wear to these sensitive systems. By way of calibration, human hair is typically 50 to 70 microns in diameter, a red blood cell is 8 microns and bacteria are typically 2 microns. The smallest particle which can be seen by the human eye without any magnification is 40 microns! To meet these demanding requirements, much finer filtration requires special media. Fleetguard offers a full range of media types in a variety of micron ratings:
■ Fuel filter media – cellulose, synthetic media and StrataPore™
■ Fuel water separator media – treated cellulose and StrataPore™

From another forum. I like this Aussie's style. Mydmax seems to have a good handle on diesel filtration. I like his ability to make things a bit clearer. (PUN intended.)

Apparently the Sprinter OEM water design is the "Detects water but doesn't really stop the water, you have to act to do that". That means it has the manual drain to empty the filter unit of the small volume that can be stopped.

"The Water detecting systems generally don't dewater the emulsified water in the fuel and require a dewatering and particulate filter to be working in conjunction with the detecting feature to realistically provide a good insurance policy."

mydmax said:
Re: Feedback on Fuel water separator filters?

Be sure of what you ask for because of the following:
There are water separators.
There are particulate filters. Just/only a filter.
There are water detectors ie Water Watch. Detects water but doesn't really stop the water, you have to act to do that.
There are filters which filter particulate matter and mostly dewater the emulsified water contained in the fuel.

Some commonly used popular/well known filters like CAV filter and have a water bowl but don't have the flow rate ability required for CRD and modern pre CRD Toyotas.

The Water detecting systems generally don't dewater the emulsified water in the fuel and require a dewatering and particulate filter to be working in conjunction with the detecting feature to realistically provide a good insurance policy.

The micron size of the filter has to be around 10 micron or less to be adding filtering ability for a CRD engine..If the micron size is around 2 or 3 micron, that is good but it also will block more easily and presents a greater restriction to flow, so it has to be a much bigger filter area to overcome this/any restriction to flow rates if that micron size is used. Much dearer too.

The Water Watch detects the water but doesn't stop water and it allows emulsified water contained in the fuel to continue to the inj pump. Not so bad on conventional diesel but not good for a CRD engine at all. With Water Watch you have to act immediately to stop fuel and water from getting to the engine.. Drain and continue with just fuel and hope no emulsified water got through. These are very at what they do though and saves the day with globs of water present..

Some filters dewater and filter but don't have a water detecting feature to warn you. It can be there and you don't know until it builds up and triggers the OE filter warning system Expensive ones do warn you. $300 upwards.

Choices as I see it:

Use a Water Watch and act immediately and pray no emulsified water is present if you have CRD.
Use above and add dewatering filter too.
Use a dewatering and filtering unit and check frequently.
Pay hundreds of money for all the bells and whistles model which detects, dewaters and filters too.


mydmax said:
Re: Feedback on Fuel water separator filters?

Some of the Raycor units are very expensive, can't think of the other one but it is also costly. I have never bought one of those. Replacement cartridges/filters are also high priced, good filter systems though and fine micron size.

This doesn't suit everyone but I put mine underneath just forward of the fuel tank on Dmax.

If you put it in the engine bay put a shroud around it, a bit like the OE filter is made and feed cool air to it with a plastic vacuum cleaner convoluted hose. This will help the system.
The flow rate is about 1/2 litre a minute on a 3 litre CRD engine and therefore the fuel isn't racing through and has time to absorb heat from the eng bay.

Many don't care and dispute the heat input as being a factor but the old and the new BT50 both have cool zone shrouded filters fitted as standard so the engineers must know something the Aussie installers don't.

If you have a digital Infrared temp gauge, shine it on the firewall and read it's temp just after a highway run on a 40 C day, I reckon it will heat the fuel quite a bit. High pressure CRD pumps LOVE COOL FUEL, infact they rely on it as part of there ability to not overheat.

There are many available filter setups and contacting filter manufacturers and a net search will help find one which suits you and the size/situation for the vehicle.

I use a Donalson P902976 filter kit 10-11micron filter which has a flow rate of 112L/H so is about 3 times more flow rate capacity than the normal flow. It has no warning of water, me check, but it has a filter which also dewaters the fuel as well as a bowl for the big lumps. May not be as good as some but seems effective and not too dear. Filter replacements are also reasonable cost so spares won't break the bank. This may not suit everyone though and Im' not forcing it on anybody either.

Hope this helps make a decision.

mydmax said:
Re: Feedback on Fuel water separator filters?


The Donaldson P902976 Kit is around $140 I think.

It isn't as fine as the one in the post above.

Filter prices? Best to ask a supplier near you or email Donaldson for current costs. Many trick places will have them.

Mine is 2011 not a 12/13 Dmax.

I am surprised a diesel crowd are promoting the fitting of additional filters on the firewall in the engine bay (and a bracket range to suit) where the filter and therefore the diesel being delivered to the engine is being heated by underbonnet temps which are quite high.

This goes against the manufacturers idea and CRD engine requirements of having COOL fuel to assist in cooling the High Pressure pump. Doesn't make sense to me. Nearly all CRD engines have a method of cooling the fuel because it is heated by it's passage through the system and has to be kept cool after the HP pump does "work" on the fuel in pressurizing it.

I have no proof but, long term I would think it will shorten component life, ie, HP pump.

The 2 micron filter is great and would help system life and the heating will shorten it again IMHO.

mydmax said:
Re: Feedback on Fuel water separator filters?


The use of a 2 micron filter after the OE filter is a good thing but it will in most cases render the restriction sensor built into the OE filter useless in detecting if the 2 micron unit is blocking.

What blocks a 2 micron will have gone through the OE filter but the larger crap will be filtered by the OE filter.

If the 2 micron is between tank and Oe filter then the Oe filter restriction sensing remains operational for both filters.

Just a note, many filters used on conventional diesels were 30 micron and for some reason that figure is being carried over into the CRD arena. Most pre filters of any substance for CRD use will be around 11microns or maybe less and they will act as a pre strainer and dewater ( if that feature is made in the filter) and also trap gobs of water in the bowl. Some have water sensing and alerts you too. 30 micron is pretty useless for use on a CRD, ok for blowflies.

Who ever fits a 2 micron just before the pump has to ensure absolutely no crap or rubbish is introduced during the fitting so the fitting doesn't cause failure. The OE filter has already been connected and works ok as designed.

Lots of people talk about primary and secondary filters. There is some confusion with this. There is two view points and must not be confused.

Some see a Primary filter as the one which is most important and the last line of defence before the engine. ie closest to the engine.

Some others see a primary filter as the one the fuel first travel through and so the main filter is then called a secondary filter.

I have noticed this mentioned both ways.

If there are two filters in series then the first one to receive flow if called a "Primary" is really of secondary importance, and therefore the Secondary filter in the line, the finer one, is of Primary importance.

if you are going to fit a finer one before the OE then it will have to be bigger flow capacity so the fineness can do it's job and not restrict or else you will be changing it every 5 km until all the crap is caught.

I like a graduated fineness for that reason, especially if out in the scrub where an endless supply of filters isn't around every bend on the gravel road.

Doing something to aid filtering is better than nothing.

Last edited:


Active member
Good for me to see the above post since it gives me more confidence that the P551615 water-separating 3 micron pre-filter from Donaldson I have installed will actually perform as hoped. But, being a "belt and suspenders" kind of guy, I'll still preview the fuel coming out of the pump before I commit to filling my van's tank - at least for a while anyway.


Engineer In Residence
For those interested here are some parts I ordered to add extra fuel filtration to my sprinter. Obviously these are part of a custom install. It is fully reversible. Other than re-routing the feed line before the OE filter, the stock system is untouched.

Here is the head assembly for the spin on filters. 1"-14 filter thread, and 1/2"NPT inlet/outlet ports.
P562261 $18

Here is the primary filter and water separator. 10 Micron, Synthetic media, 120GPH, has drain. 95% emulsified water removal.
P551001 $16

This the 3 micron secondary filter. Cellulose media, 120GPH. No drain.
P551313 $11

Also needed for the T1N, 3/8 Fuel hose, clamps, 1/2"NPT-> hose barb fittings.

The total should be around $100-120 for materials. Obviously mounting and whatnot could be difficult depending on individual skill level. Note that all of these filters without the clear filter bowl are rated to 100PSI. So they are safe to use on the pressure side of sprinters with the OM647 engine.

Edit: I got my filters from here. You need to know the part number to order.

Edit 2: Here's a photo of the setup (not installed yet).

Last edited:


Active member
Also needed for the T1N, 3/8 Fuel hose, clamps, 1/2"NPT-> hose barb fittings.
Don't know about the OM647, but for me 5/16" ID hose was required for the filter input line (to fit snugly over the fuel line from the tank) and 3/8" ID hose to the OEM filter. Also, I used SAE 30R9 spec fuel injection hose for both w/ Viton liner (my research suggested it would be more resistant to warm diesel than the 30R7 spec hose w/ neoprene liner).


2008 3500 170"ext. 3.0 V6 OM642.993
Fuel Injection Hose Clamp

If replacing clamps on a ......
2002-2003 Sprinter-order 4 x 13mm clamps
2004-2005 Sprinter-order 3 x 13mm clamps & 1 x 15mm clamp
2006 year Sprinter-order 9 x 13mm clamps & 1 x 15mm clamp
2007-2009 Sprinter-order 6 x 13mm clamps & 6 x 15mm clamps


Aqua Puttana

Poly - Thread Finder
Don't know about the OM647, but for me 5/16" ID hose was required for the filter input line (to fit snugly over the fuel line from the tank) and 3/8" ID hose to the OEM filter. Also, I used SAE 30R9 spec fuel injection hose for both w/ Viton liner (my research suggested it would be more resistant to warm diesel than the 30R7 spec hose w/ neoprene liner).
The OM 647 original filters are listed 8 mm (1/4") inlet and 10 mm (5/16") outlet.

I'm certain the reason for the two different sizes is to prevent the hoses being incorrectly installed one for the other during filter changes. The OM612 and OM647 fuel pump each provide enough volume that both the inlet and outlet being 1/4" would be fine for flow.


P.S. - I searched for an equivalent Mahle KL 313 filter with 1/4" inlet/outlet to avoid needing the reducer union in my pre-filter installation. I wasn't successful in finding one. That style filter all seem to use different inlet/outlet diameter for "polarity".
Last edited:

Aqua Puttana

Poly - Thread Finder
Fuel Injection Hose Clamp

If replacing clamps on a ......
2002-2003 Sprinter-order 4 x 13mm clamps
2004-2005 Sprinter-order 3 x 13mm clamps & 1 x 15mm clamp
2006 year Sprinter-order 9 x 13mm clamps & 1 x 15mm clamp
2007-2009 Sprinter-order 6 x 13mm clamps & 6 x 15mm clamps

Good information. There are different clamps needed.

That is for the hose clamp to go around the outside of the hose.

The OM612 fuel filter doesn't need pressure hose (thinner wall clear hose).

The OM647 and newer engines use thicker wall pressure rated hose.

I don't know why they changed for 2006, but I'll deal with that for my 2004 and 2006 vans. The filters 2004 - 2006 are the same.

:2cents: vic
Last edited:


Active member
The OM 647 original filters are listed 8 mm (1/4") inlet and 10 mm (5/16") outlet.
My math says 8 mm is 0.315", while 1/4" is 0.25"; likewise 10 mm is 0.394" and 5/16" is 0.312".

Aqua Puttana

Poly - Thread Finder
My math says 8 mm is 0.315", while 1/4" is 0.25"; likewise 10 mm is 0.394" and 5/16" is 0.312".
Ha ha. Good one.

I know that you're aware we're dealing with rubber hose and not a steel to steel interference fit where that 6 or 8 thousandths would be critical.

NPS - 'Nominal Pipe Size' and DN - 'Diametre Nominal'

Diameter Nominal DM(mm) = Nominal Pipe Size NPS (inches)

6 = 1/8
8 = 1/4
10 = 3/8
15 = 1/2
20 = 3/4
25 = 1


My experience with Nominal Hose size on 10 mm hose barbs. 5/16" is a bit snug. 3/8" can sometimes seem a little loose, but not so bad that it can't be snugged tight with a proper clamp. I prefer to start with slightly snug.


5/16" = 7.9375 mm

3/8" = 9.525 mm
Last edited:

Aqua Puttana

Poly - Thread Finder
A Mann fuel filter which is the same as the Mahle 313.

Mann WK 820/1


Other equivalents


ASHIKA 30-M0-002
BOSCH 1 457 434 437

L 440
L 444


DT 4.66665


FRAM P9635


HOFFER 7690328
FD 540
MANN-FILTER 40 11558 94540 4
MAPCO 63850

646 092 00 01
646 092 03 01
646 092 05 01

P.B.R. AG-6094
UFI 24.436.00
VALEO 587509
Last edited:


Formerly Type2Teach
So what are your maintenance schedules now that you have pre filters before your stock filter?
Great setup, by the way. :thumbup:


Engineer In Residence
So what are your maintenance schedules now that you have pre filters before your stock filter?
Great setup, by the way. :thumbup:
With my spin-on donaldson filters, I am going on 60k+ miles without changing any of them... I am planning to replace the spin on filters here soon. The factor filter will stay in place, as it is only there to catch crap that might get introduced when I replace the spin-ons.

Top Bottom