OM612 Fuel Filter Priming tool

hkpierce

'02 140 Hi BlueBlk Pass
Thanks goes to Dr. A for this idea; and I see that NelsonSprinter does the same but without the adapter - MityVac only: https://sprinter-source.com/forum/showpost.php?p=267947&postcount=4
In 2003 I posted the turkey baster idea for priming the OM612 fuel filter canister and related lines. Others have suggested pressuring the tank to force fuel up the line and into the canister. Dr. A recommends vacuum instead.

ADAPTER:

The hardest item to get is the Voss connector. I got mine as I was replacing the fuel line from the fuel filter to the low pressure pump due to a broken leg.

The nylon line really is tight on the connector. I used a heat gun to remove the nylon line.

PrimeHeatgun.jpg

Strip off the legs and white ears. These are taken off to make it easier to do a quick change out
PrimeStrip.jpg

Once the connector is free, I replaced the O-ring with a new one. Attach a small diameter fuel line - only about 6 inches is needed. If you can find clear line, so much the better (I didn't - so used some black hose I had lying around).

PrimeModify.jpg

USE:

The adapter mounts on the load side of the low pressure fuel pump. That is the top Voss connector on the pump. To get to it, disengage the vacuum line that goes in front of the pump for working room. Disconnect the Voss connector and prep it with silicone grease (check O-ring as it may need to be replaced). Put silicone grease on the adapter, and mount it in the Voss fitting.
PrimeMount.jpg

Now attach a MityVac. I like using a bit of clear line at the MityVac such that I can see when the bubbles stop. This technique almost guarantees that there will be no air from the feed line from the tank through the fuel filter canister and through the low pressure pump. Once the bubbles stop, the goal is to unmount the adapter and reconnect the fuel line as quickly as possible, as gravity acts fast with diesel.
PrimeVac.jpg

This adapter and priming technique significantly reduces the amount of time needed for the starter to operate. This is really important if the battery is running near the 11.5 volt no-start barrier. All the fuel that is vacuumed in goes through the proper path and is properly filtered. There are no spillage issues - really clean and neat.

Put the adapter in the same box as your spare fuel filter, along with some silicone grease, in the van, and carry it with you all the time.
 
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Nova

New member
How long do you need to pump the mityvac before you get fuel flowing. I think I must have a leek some where because it does not build up pressure.
The MB dealer used A LARGER VACUUM and was able to get it started but it will not rev over 2500 rpm with out getting air in line and then the clogged fuel filter light comes on.
Restart and light goes off and air goes away until it reaches 2500 rpms any ideas? 2003 dodge sprinter.
 

jackbombay

2003 158" shc
it will not rev over 2500 rpm with out getting air in line and then the clogged fuel filter light comes on.
Do you have air in the fuel lines when the van is running? I'd check that all the orings are undamaged and not leaking air.
 

rjz5400

Member
I've been planning to build one of these for a couple years but need the Voss connector, any ideas on sourcing one other than buying a 20$ hose to cut up? I got one from Dr. A a long time ago and it is cracked!!! (Possibly from my efforts to remove the factory fuel line)

I don't want to jb weld up a fuel tool, But I'm tempted!!

Possibly the OP? Thanks for the writeups!
 
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Williaap

New member
Changed my OM612 fuel filter the other day and with a 50mL syringe I was able to use the nozzle slowly inject fuel into the lines to remove air, as well as being able to pull a slight vacuum on a line (though I didnt even need this feature). The syringe also worked great for filling the filter and purging it of air! Also they are dirt cheap.
 

vanski

If it’s winter, I’m probably skiing..
hey guys.. just wanted to post my similar but different way of doing this. took me all of 10 minutes. and this isn't just to prime the filter, it primes the entire line.

i had never worked on the om612, went to replace the fuel filter, got a bad FF that didn't seal properly at the water in fuel sensor, got air in, and the vehicle went from running rough, to stalling, to not starting very quickly. after looking a little deeper, i had no fuel between filter and the low pressure pump.

Anyhow, when you're in a pinch, don't have a jug of diesel around, and don't have the time to track down specialty Voss connector parts, here's an easy and very inexpensive way to go about it:

1. Make sure you have the appropriate Fuel Filter properly fitted. MBZ, Hengst, maybe Mann. And make sure all the o-rings are not cracked and or split. and use grease around the o-rings to make sure they go on properly and seal. Install all the fittings other than the fuel entrance portal for this procedure.
2. Acquire (i happened to have on in my garage) one of those cheapO fluid pumps that have variable nozzles types and have a 1/4 - 1/2" tube coming out the end. I think I got mine at NAPA once upon a time to do a rear differential oil change for like $8.
3. Disconnect the exit Voss connector at the low pressure fuel pump at the front of the motor. Disconnect it by pushing the plastic c-clip in, not pulling it out, then gently wiggle the connection out after the c-clip has been pushed in. note - the reason for doing this is so the air has someplace to go. if you don't do this step then the vacuum system keeps the diesel from working to the low pressure pump
4. At the fuel filter, connect the blow (compared to suck) end of your liquid pump onto the fuel filter fuel entrance connection. I didn't need to make this a clamped connection (since we're pushing fuel compared to pulling)
5. At the fuel line that goes to the fuel tank, connect the suck end of the your liquid pump.
6. Before pumping, consider what you're trying to accomplish here.. you're trying to get all the air out of the line, get some fuel into the low pressure fuel pump, and trying not to lose any of the fuel once you disconnect your pump..
7. Pump until you have a small amount of fuel leaking out the exit Voss connection spot at the low pressure fuel pump on the front of the motor. Make sure there is little to no air in the line.
8. Before you pull the connection at the fuel filter, remember #6 and what's about to happen. Gravity is not your friend and will try to push out the diesel. I got my left hand index finger ready and then plugged the fuel entrance line at the fuel filter when I pulled my fluid pump off.
9. While plugging the fuel filter hole with your left hand, wiggle out the fluid pump connection at the line going to the fuel tank and QUICKLY connect the fuel line going to the tank on to the fuel filter fuel inlet portal.
10. Tighten the line up at the fuel filter
11. Reconnect the Voss connector at the exit point on the low pressure fuel pump at the front of the motor. Don't forget you need to pull the c clip to fasten it compare to push it (counter intuitive in my opinion).
12. Check all your connections one last time
13. Crank engine... mine took about 10 seconds before it fired. It understandably ran rough for a few minutes before I pressed the pedal down a LITTLE then all seemed good.

Hopefully my little ad-on here provides some value for someone without a jug of diesel around, and someone not wanting to order specialty parts... you could also bring the little liquid pump in your truck and do this procedure with nothing more than a screw driver and the pump.
 
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bcman

Active member
I just finished my second fuel filter replacement in my OM612. The first time, no amount of cranking would prime the pump, and had to drive to a gas station to buy a gallon of diesel, and jerry rig a solution with a syringe and vinyl tubing. This time I bought a replacement fuel line D (mine was cloudy and brown), and cut one of the Voss connectors out of the old one to make this tool with a MityVac. Worked like a charm! I've got the other Voss connector from my old D line available for anyone with an OM612 that wants to make a similar tool.
 

bcman

Active member
I just finished my second fuel filter replacement in my OM612. The first time, no amount of cranking would prime the pump, and had to drive to a gas station to buy a gallon of diesel, and jerry rig a solution with a syringe and vinyl tubing. This time I bought a replacement fuel line D (mine was cloudy and brown), and cut one of the Voss connectors out of the old one to make this tool with a MityVac. Worked like a charm! I've got the other Voss connector from my old D line available for anyone with an OM612 that wants to make a similar tool.
voss connector gone.
 

Lojack72

'02 DIY adventure van, 300K miles (210K by me)
Just changed my filter again today at 262K miles. I have a 3/8 Check Valve installed just before the filter inlet & connect this simple boat primer bulb on the installed filter before reconnecting the feed line- a solid low tech option.
I'm tempted to leave the bulb in there full time, but have seen this part leak on boats before so use it only for filter changes.
65306873350__0F03B0B5-E1CC-4440-8405-7CEE8A949CEA.jpg
 

newbie-t1n

2003 Freightliner T1N
Just changed my filter again today at 262K miles. I have a 3/8 Check Valve installed just before the filter inlet & connect this simple boat primer bulb on the installed filter before reconnecting the feed line- a solid low tech option.
I'm tempted to leave the bulb in there full time, but have seen this part leak on boats before so use it only for filter changes.
View attachment 193546
Interesting - getting ready for my first OM612 fuel filter change - would you mind adding a little more detail - does the primer bulb push fuel up to the low pressure pump? Do you remove the top Voss connector on the low pressure pump? Or hasn't air gaps been an issue between the filter and the low pressure pump?
 

220629

Well-known member
I'm not Lojack72.

Interesting - getting ready for my first OM612 fuel filter change - would you mind adding a little more detail - does the primer bulb push fuel up to the low pressure pump? Do you remove the top Voss connector on the low pressure pump? Or hasn't air gaps been an issue between the filter and the low pressure pump?
There should be no reason to mess with the fuel pump. Use the hose connections on the fuel filter.

It appears that Lojack72 has installed a check valve to use the bulb before the filter. The check valve prevents the fuel from traveling back to the tank when the pump bulb is disconnected.

Rather than adding a check valve, my method would be to assemble everything on the fuel filter up to connecting the outlet hose. The pump bulb can be connected to the fuel filter outlet stub to pull fuel from the fuel tank up into the filter. When the bulb pump hose is disconnected some fuel may travel back into the tank, but the fuel filter should remain basically filled aka primed to reduce cranking time. Connect the fuel filter outlet hose and you should be good to go.

Don't overtighten the WIF drain unit. Too tight is not good. The rubber O-ring seal just needs to be properly positioned. Too tight can distort things and cause air leaks.

vic
 

newbie-t1n

2003 Freightliner T1N
I'm not Lojack72.


There should be no reason to mess with the fuel pump. Use the hose connections on the fuel filter.

It appears that Lojack72 has installed a check valve to use the bulb before the filter. The check valve prevents the fuel from traveling back to the tank when the pump bulb is disconnected.

Rather than adding a check valve, my method would be to assemble everything on the fuel filter up to connecting the outlet hose. The pump bulb can be connected to the fuel filter outlet stub to pull fuel from the fuel tank up into the filter. When the bulb pump hose is disconnected some fuel may travel back into the tank, but the fuel filter should remain basically filled aka primed to reduce cranking time. Connect the fuel filter outlet hose and you should be good to go.

Don't overtighten the WIF drain unit. Too tight is not good. The rubber O-ring seal just needs to be properly positioned. Too tight can distort things and cause air leaks.

vic
Thanks Vic,

I can see how the pump bulb would attach to the supply line and the filter inlet (before the filter as you say), but I'm not catching how to attach the bulb to the "fuel filter outlet stub". Are you referring to where the Voss connector attaches to the fuel filter? Wouldn't I need a Voss connector? or would it pull enough vacuum by just "stuffing" the hose attached to the bulb inside the outlet stub? Maybe that is what NelsonSprinter is showing here 02-03 OM612 Sprinter Fuel Regulator O-Ring Kit | Sprinter-Source.com . I can't quite make it out from the picture.

From reading earlier in this thread, I thought there may be a risk of losing prime due to air entering the line between the filter and the low pressure pump - hence the vacuum method from the low pressure pump shown earlier in this thread by hkpierce. But maybe your suggesting that risk is relatively low if the air gap in the supply line before the filter is eliminated?? I've read the manual and it only says fill the new filter with diesel.

I don't have a Voss connector (at least not yet - I've contacted Csansom001 to see if he has one) and so was interested in Lojack72's idea and whether it pushed fuel up to the low pressure pump since the primer bulb would create pressure as well as vacuum once full of fuel with the check valve in place.

I really appreciate all the help you and others provide to us who are new to fairly old sprinters - probably mostly class b motorhomes like mine.
 

220629

Well-known member
Thanks Vic,

I can see how the pump bulb would attach to the supply line and the filter inlet (before the filter as you say), but I'm not catching how to attach the bulb to the "fuel filter outlet stub". ...
:hmmm: I was assuming a different style fuel filter. My apologies.

For the pump bulb to suck fuel a rubber hose placed over a stub, or a hose of proper diameter to fit snugly inside a fitting should give enough seal. I haven't tried that though.

To my knowledge MB doesn't officially recommend pre-filling the fuel filters. If the fuel system is tight (absolutely no leaks), cranking the engine will eventually pull fuel through the system to start the engine. Pre-filling the filter does reduce cranking time after a fuel filter change. In my mind that is a good thing.

The check valve fuel bulb method would push fuel into more of the system.

Adding an electric pump has been discussed. The electric pump could be operated with a manual switch for when needed. Will it work as expected? It should. Is it worth the cost and effort? :idunno:

Some info and discussion is in this thread.


vic
 

lindenengineering

Well-known member
Old fashioned method from off the Cotswold's , in the 1950's/1960's on a freezing cold day when all diesel powered vehicles had similar fueling set ups like this 2003 T1N van
Stuff a ball of rags into the filler tank neck.
Slide air line with blow gun into the side of the rags and 'Lightly" pressurize with air.
Open the bleed screws & injector supply pipe and watch it until fuel pees out, with no air in the expelled flow.
Bleed out through the injector lines and fire up.

Surprise surprise!!! Many year later how did they bleed bus or truck on the factory production line?
The Gloucestershire/Zummerzet Farm Boy Regiment bleed method.
Dennis
 
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newbie-t1n

2003 Freightliner T1N
Old fashioned method from off the Cotswold's , in the 1950's/1960's on a freezing cold day when all diesel powered vehicles had similar fueling set ups like this 2003 T1N van
Stuff a ball of rags into the filler tank neck.
Slide air line with blow gun into the side of the rags and 'Lightly" pressurize with air.
Open the bleed screws & injector supply pipe and watch it until fuel pees out, with no air in the expelled flow.
Bleed out through the injector lines and fire up.

Surprise surprise!!! Many year later how did they bleed bus or truck on the factory production line?
The Gloucestershire/Zummerzet Farm Boy Regiment bleed method.
Dennis
Thanks Dennis,

I was raised on a farm also. the tractors we used had a small lever pump built on top of the filter housing so you could just pump by moving the lever up and down and the job was done. Seemed simple.
 

Cheyenne

UK 2004 T1N 313CDi
The first time I changed the filter on my UK spec T1N with the OM611 engine which has an identical fuel system to the OM612 I was taught by an MB trained tech to fill the new filter with fresh diesel until it would take no more then swap them over. Every time I have done this since the engine starts right up without any hesitation.

Seems far simpler than jury rigging non return valves and bulb pumps!

Keith.
 

lindenengineering

Well-known member
Yes !
Well common practice really, you should ALWAYS pre filters where possible . Saving you time and the ever present embarrassing "No Start " & impromptu Brit workshop "barbershop" choir
Singing
"Why was he borne so beautiful" !~!!!! :)
Dennis
 
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skigull

2002 t1n 2500
my 2002 has been a nightmare and i would've sold it long ago if not for this forum.

i changed my fuel filter yesterday, pre-filled the fuel filter, bled the air out using the bleed valve, but when i cranked i could not get the engine to over. i tried cranking it for 15 secs or so, then took a break and repeated. i could not get it to start. now it barely cranks before it just clicks. im worried that i blew out my starter. is it possible that there was a leak and no fuel was getting to the engine? if so, would that cause a no crank issue, or is that directly related to the starter?

im new to working on cars and have never done any work prior to owning this van other than replacing the battery and refilling the washer fluid. sorry if this is a bad question but i appreciate the help.
 

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