Diesel Moly Flush and Fuel Filter replacement on 2002-2003 Sprinter T1N 

I would not do this with every fuel filter change. It is a cleaning that has worked for some. Our van must need something more than cleaning. These injectors passed leak off test in another video, and smooth running test in DAS. They will be shop tested tomorrow. Stay Tuned.

They can also be a cause of leaking or letting air in so an 2002-03 will not start without re-priming ! Tip from another Sprinter guy was just replace with a filter with one without the water bleed valve, 04-06 don't have this & water in the filter isn't an issue, changed mine & never had a problem between filter changes.

If your van has an in-tank fuel pump this is not a good idea. North American Sprinters before 2004 don't have a pump in the tank, so it would be fine.

I hope the take-away is: The flush is simple and easy with the mechanical fuel pump of the 2002-2003 but we didn't find a miracle cure we hoped for. These injectors will be professionally shop tested tomorrow. Stay tuned for that video. If we find the injectors are good and the van's problem is somewhere else..... We proved nothing, but showed the process. I think the advice was, "keep them wanting..." LOL

The low pressure pump on your van is at the front of the engine just above the high pressure pump. It sucks fuel from the tank and, yeah that sucks! Some folks have used a shop-vac to pressurize the fuel tank while starting the van. Others have loosened a fuel injector line to relieve air back-pressure. Be VERY careful if you do this. When the van starts the pressure in that rail is EXTREME and any fuel flying out of the open line can cut like a knife or worse, get into your skin and bloodstream.

@@FloridaVanMan I actually found another solution! Bought a few feet of 3/8”ID clear tubing, hooked it up to the filters inlet, held it high and filled the tube. This created a “beer bong” type of system to feed diesel enough to start it. It ran for a couple mins while it burned through what was in the tube. The I reconnected the tank feed and it turn over rather easily.

A little diesel in a spray bottle, 2 or 3 sprays into the elephant tube while glow plugs warm, and start the van. Air should pass the lines quickly once engine starts.

I’ll give it a shot. Thanks man!

What is elephant tube?

Starts on diesel in the rail and lines, but I expect it will start on Moly also. We simply removed the lines from the tank and filter. Since there is no in-tank pump on your '02-'03 models there was no need to do anything more than prevent dirt from falling in them. The purpose of putting both hoses in the can like this is because the Moly will dilute if returned to the tank with diesel. Supply and return lines in the can like this keeps the Moly concentrated and recirculating until it is almost all used full-strength. It takes a while to burn a full can, maybe 10 minutes from what I remember. It will flush out of the filter in a few seconds, dumping most the Moly via the return line to the tank.

Correct; there is no in tank fuel pump. The fuel is drawn up by the fuel tank into the low pressure fuel pump (the top smaller fuel pump, with clear lines going into it). You should be able to see if the clear lines have bubbles in them while it is cranking. Those clear lines leaking and letting air in is an extremely common issue on 02/03 Sprinters. The 04/05/06 virtually never have this problem unless the in-tank fuel pump fails. There is still a sensor in the tank though, when you put the key on you should be able to see the fuel level. Another tip: Don't use ether on a Sprinter! It's way overkill for it and can actually harm the engine and crankshaft when it fires, just put diesel in a bottle and spray into the intake manifold.

@@FloridaVanMan Replaced all the clear fuel lines (might be a good video to do, I broke the clippies under the low pressure pump and used zip ties on either side to hold the lines up from the serpentine belt).. what a pain! Under the top engine cover looks clean, I do have an Injector return line on standby but the current one looks fine. Tried to do startup procedure with the IV gravity diesel tank method, noticed the Fuel filter water sensor was leaking..ugggg.. reseated and got it to start and move under its own power! Engine seems OK. I think the fuel filter water sensor is still sucking a small amount of air so am ordering the No leak filter in your video. Thanks for the help from you both!

Liqui Moly was a hopeful idea to clean the fuel system. Some folks gave it high recommendations but it did not help our problem. Since cleaning the fuel system is a frequent topic and this is an approved method, we decided to share the process. It didn't work this time, but we will certainly try it again on a later model T1N that may or may not be helped by cleaning the fuel system.

My first reply missed the point of your question. We could have just filled the filter with diesel or Moly, but we wanted to recirculate pure Moly to really scrub the fuel system. As we have done it here, the overflow returns to the can rather than going back to the tank and getting diluted with diesel.

Just tied it up out of the way. Nothing special.

Florida Van Man thanks. I am only a little worried about not having a water separator sensor /drain. But I used this filter seen in the video.

@@nicholasmartin7922 ULSD is so heavily regulated in the USA we don't need to worry too much about water in out fuel lines. I'm over 50 and only thought I had water in my fuel once, long ago. Turned out to be an electrical issue causing misfires (gas engine). When playing with veg-oil fuel I had suspended-water in the oil, which apparently just passes right through the filter and WIF sensor. :(

@@nicholasmartin7922 How many times has the water separator / sensor saved you in the past? I'm guessing it never has, and never will, so removing it is not a big deal.

@@FloridaVanMan did you reattach the sensor to the connector? if not does this cause any light issues on the dash?

Like oil change maintenance is needed, high mileage an easy flush and hope and prayer keeps it going

We were hoping to fix a smoking habit. It may not be an injector issue but a good system cleaning seemed a good place to start. It did not help, but we will try again on the newer T1N with in tank pump. That will be a bit more involved and hopefully have more impact on different mild symptoms.

@@FloridaVanMan Interesting stuff, thanks for the reply

Keep the sensor from old filter plugged in and tie it up out of the way. it will not have a place in the new 'no-leak' filter and will not trigger a light when tied up.

@@FloridaVanMan thanks for the quick reply boss

The engine in this video was replaced before the van was put back on the road. This diesel cleaning did not help the trouble this engine has and it will probably be rebuilt eventually. it runs but smokes and sounds not great.

The Moly is an often discussed and occasionally bragged about cleaning process for the injectors and fuel system. We didn't brag about it here because it didn't do any good for this van. There are too many independent accounts of first hand stories on the FB groups to call it Myth-Busted, but we certainly didn't find a miracle cure we hoped for. These injectors will be professionally shop tested tomorrow. Stay tuned for that video.

Move where it's warmer? Ha ha. I kid, but only kind of.

Swap with OM647 intake manifold. Unless a tool exists, I don't see any way to get those glowplugs out without pulling the engine and taking the intake manifold off.

@@FloridaVanMan tanks for ur reply. I'm putting the parts together to do just that but I thought you might buy me some time and show the changing which would complete ur sprinter basic 101 basics.

This 2002 we have now has become quite the *educator. lol (sad face). It may get the OM647 intake upgrade before it is all done. If I need to get at the fuel rail, you can bet this manifold will get the Big YEET!

@@FloridaVanMan Other than the manifold and EGR valve (with gasket), are there any other parts required to make that switch?

No reason I know of. It has plenty of lubricant and *fuel to safely carry-on. But what are you hoping it will do?

@@FloridaVanMan I have an odd rail pressure issue where it stalls when I release the throttle too quickly, rail pressure goes down to zero. my assumption is a sticky relief valve which doesnt shut fast enough, will try this before I replace valve

I've not looked at a Vito, sorry.

Sounds like you have a failed wheel speed sensor causing the ABS to believe one or more wheels is locked and sliding. A compatible code reader will help diagnose by watching wheel speeds in live data.

@@FloridaVanMan Do you look at vans and tell people whats wrong with them? If so would you be willing to look at mine i happen to be in Orlando Florida.

I do work on vans for Patreon members. patreon.com/Florida_Van_Man?Link& @@LilOrphicMusic

Sorry for being slow to respond. I've been meaning to crack the books and figure out what pin(s) on the OBD port should have 12v and recommend testing those. But I haven't cracked the books or found the "Sprinter OBD pinout" online.

@@FloridaVanMan thanks for your reply if you have any suggestions please let me know thanks