fuel drip

I just had all of my glow plugs replaced, along with fluids (tranny, oil, coolant). In the process of replacing all of the glow plugs, or any of the mentioned fluids, would there be any obvious way to end up with a fuel leak?

The reason I ask is that prior to purchasing my 2008, I extensively crawled around underneath and everything was bone-dry. After the service, and driving a total of 11 miles home, and then one more trip 9 miles out to a Home Depot, I noticed a small puddle under the vehicle in the Home Depot lot. I initially suspected one of the fluids that I had serviced, but it seems to be diesel. The cross-member (steering rack) is wet and there has been freeway speed induced light over spray of the undercarriage from the cross member back (as expected).

There are no warning displays and the van seems to be running like a champ.

Any ideas? For example, do fuel lines need to be disconnected for any of the services that were performed? Or, is there a possibility that something is so close/tight that it may have been accidentally dislodged or damaged?

It's back at the dealer at this time and I'm anxiously awaiting their diagnosis....

Fuel filter clamps, and or water in fuel drain first come to mind.

Icarus

A 'compromised' leak oil line could also be a cause, but that is usually more than just a "drip". The leak oil lines can be damaged by an incorrect replacement of the engine cover(s).

That happened to my NCV3 when being serviced at a Dodge dealership, but fuel immediately spewed all over the shop floor when the mechanic started the van.

Incorrect, classic worm gear fuel line clamps can cause a fuel drip at their installation site.

The in-tank lift pump will supply in excess of 50psi of fluid pressure to the fuel filter. In fact, it takes 72.5 psi to trigger the fuel pressure relief valve which, when open, will divert fuel back to the tank.

This kind of clamp:



may deform the hose so it doesn't seal well enough to withstand the pressure produced by the lift pump to the filter.

Classic American diesel engines - until very recently - only supplied about 20-30 psi of pressure to the fuel filter.

This type of clamp is required for a Sprinter. It's a full-band, fully sealing fuel line clamp.



NAPA sells these. They're usually stainless steel and you need 13mm and 15mm clamps for each side of the fuel filter.

-Jon

Developed a leak in the short fuel return hose @ about 105k. It's about 2" long, just to the right of the fuel filter. Most puzzling it was intermittent. Leaked 3-4 times over a couple month period. Dealer replaced with "bulk" fuel line which deteriated within a month. Proper diesel approved hose is difficult to find. I called numerous chains. Ended up getting some from a marine/ boat shop.
+ 1 on the specific clamps. Some of the factory crimp style clamps may have been substituted with the worm style or other non approved.

Thanks for all the info! I'll let you know what they say...

jdcaples said:

Incorrect, classic worm gear fuel line clamps can cause a fuel drip at their installation site.


[snip]

-Jon

Click to expand...

Great info, Jon!

Well, it was the line from the filter to the fuel rail. I was told that it had split from the inside, which seems strange, but hey...they over-nighted the part and $100 later and one day later, I'm back to rolling.

The conversion continues.

Evil Patrick said:

Well, it was the line from the filter to the fuel rail. I was told that it had split from the inside, which seems strange, but hey...they over-nighted the part and $100 later and one day later, I'm back to rolling.

The conversion continues.

Click to expand...

Not for long, though.

So, I smelled the fuel again. I crawled under the vehicle and things were still wet and had been dripping. CRIPES! I fired it up and let it idle for a good 5 minutes. No dripping. Then, I took the vehicle for a 2 mile spin around the block a couple of times. Pulled into the driveway, shut 'er down, and threw a big slab of cardboard under the engine bay to see what would drip out, seconds later, it started coming down at an alarming rate, like an 8th of a cup had been splatted on the motor, somewhere above and made its way down, not only from the steering rack area, but the front of the oil pan as well. WTF,BBQ?!

I called the service manager and probably sounded quite perturbed, as I was frustrated that the previous diagnosis was not only incorrect, there was no post-work testing to see if the problem had been solved.

I'm not at all sure what the real issue is, but this puppy was bone-dry when I bought it and turned a splashed mess after the big, "all fluids" service. I just dropped it off again. The service manager hinted that he acknowledged the previous "fix" was incorrect and said "this will probably be on our dime". We'll see.

I hate to feel like I'm losing faith in my local Mercedes Sprinter mechanics. If they can "make it right" this time, I may find forgiveness.

The fuel path is:

Tank -> lift pump -> fuel filter inlet -> fuel filter outlet -> high pressure fuel pump -> common rail

a) -> injectors -> combustion chamber
b) -> leak oil line which just returns warmed injected fuel to the

Tank -> lift pump -> fuel filter inlet -> [etc, etc, etc]

At this point, I would request they remove the engine covers - left cover, right cover and center cover - and show you the leaking part before they repair it.

-Jon