This past weekend I replaced the fuel filter and fuel pump in my 2013 S550. It was a pretty straightforward process thanks to some notes on this forum and some YouTube videos. However, when I start my car after a few seconds I hear a echoing clunk/thud as the fuel pressure pushes off one of the lines attached to the bottom of the fuel filter and the engine stops for lack of fuel. I've tried five or six times now and the line keeps disconnecting once fuel pressure is reached. So what I did to fix this situation, I put a zip tie around both lines (snug but not overly tight) and that has kept the problematic line from popping off.

Having said that, I'm wondering if I'm missing a securing clamp (like 6a in the attached photo) of some sort. I looked in the gas tank and didn't see anything below and I don't believe I broke the built in clamp on the hose. But the built-in hose clamp by itself isn't strong enough to secure the hose under pressure so if anyone has photos or experience with similar issue, would appreciate any input. While my zip tie solution is working I'd still like to know why just reattaching the line and engaging the built-in hose clamp (two small black latches that push down) doesn't provide a secure connection. I decided to change the pump and filter as I kept getting low fuel pressure codes (those are gone now). Perhaps the hose clamp itself was beginning to fail and I broke it during the filter change (but there are no stray or broken pieces anywhere that I can see).

I didn't take a photo of the replacement fuel filter itself outside the tank to show the hoses (I'll do that tomorrow most likely). But one thing I noticed is that most of the DIY videos show a filter with three hoses at the bottom of the filter and a securing clamp on the end of each hose and a clamp that holds all three hoses together. I didn't have any of those sorts of clamps on the my fuel filter hoses. The filter and pump were factory as I had to break a coating/sealant that was sprayed over the retaining nuts holding the filter and pump in place. So I don't believe there was any chance a previous replacement occurred.

I have attached a photo of the old filter and the fitting that keeps losing connection with the hose. And also from WIS the photo of what pre-2013 filters/clamps look like.

 

Perhap a securing clamp 6a is mising, if it in place then it's impossible for hose disconnecting.

 

One way to tell if fuel filter was worked on or replaced if performed by a MB dealer is to have local dealer pull Vehicle Master Inquiry (VMI) to check. To the best of my knowledge MB does not offer these fuel lines and/or connectors separately from fuel tank if you want OE may need to replace fuel lines if you can find used, alternative makeshift hose clamp.

 

Thanks, konigstiger. BTW, indirectly thanks to you (supplied datacard) I found and purchased my 2013 S550 back in February 2020. I have the VMI report and doesn't show any work done to the fuel filter/pump. The photo below I took prior to removing the filter. You can see what looks to be factory paint/sealant over the retaining ring/nuts. So I'm fairly confident between VMI and visual inspection that the filter was a factory installed part.

Given my fuel filter and lines look much different from the WIS diagram, what I'm really hoping is someone else with a 2011-2013 S-Class that has the newer fuel filter like I have can post some photos or at least confirm that I am missing a securing clamp or not. This weekend I will post a photo of exactly how my filter configuration/hoses look like. I looked all the way down the fuel line and at the bottom of the fuel tank and I don't see a securing clamp anywhere and I don't recall having to remove one when I switched out the filter (I should have taken before and after photos of everything). I have a feeling that maybe the tabs built into the hose have weakened such that they won't secure the hose anymore and I will just need to roll with my zip tie solution. The low fuel pressure code has cleared and the car runs normally if slightly smoother idle now. If other vehicles with the same filter don't have a securing clamp then at least that would satisfy my curiosity as I don't plan on buying a new tank just for a new hose/clamp if I can avoid that.

 

I noticed you did this back in December, what was the final solution as I have a code P0087 and am trying to figure out what to do about it.

My Car is 2013 S550 Base Model with 80,000 miles.

 

The short answer is that I used a few zip ties. I didn't want to tighten down on the fuel line itself, so I put one zip tie loosely behind the fuel line connector which is bigger than the line itself. Kind of like a harness. Even though I wasn't having problems with both lines, I made a sort of daisy chain of zip ties to hold both lines in place and then anchor them to the base of the fuel filter. Once anchored to the base of the fuel filter, they were very snug. By the way I never had this issue with the connectors on the fuel pump.

If you notice in Konigstiger's post, the diagram shows a different fuel filter with three parallel connections on the bottom. It also has a "securing clamp" for one of the lines (and in a couple YouTube videos there's also a clamp that holds together all three lines). Anyhow, that appears to be a pre-facelift filter. Not sure when/why they changed the fuel filter, but the 2013 filter is different. I even searched the bottom of the fuel tank thinking maybe I had a securing clamp that somehow fell off but didn't find anything. I even tried using the original filter and the line would no longer stay on so I must have broken or bent the plastic clip somehow even though there were no pieces/parts in the tank and the connector looked like it had all the clips and they appeared to work (or maybe just disturbing the connector after nine years submerged in fuel, it weakened just enough to no longer work?). Anyhow, I went to the dealer asking if I could buy fuel line components (there's hoses/wiring harness inside the tank), but they weren't able to identify any part numbers for components inside the tank. They also took a look at my solution and said it looks like it will hold but obviously isn't an approved Mercedes solution.

Because I like to take extended road trips in the S550 and in the back of my mind I know I have this fuel line rigged up that could potentially fail (worse case is remove the seat pull out the filter and reattach the line - I even kept the tools and extra zip ties and gloves in the trunk in case I needed to do a roadside repair), I decided to just replace the whole damn tank for peace of mind after driving with the zip ties solution for about 6 months/6,000 miles. New tanks come with the pump and filter already installed and factory sealed. But you have to drop the rear end of the vehicle to get the tank in, so it cost about $4k! (thanks Amazon stock) to replace the entire tank.

Bottom line: Removal and replacement of the filter and pump are pretty straightforward (pump, filter, seals <$400). Many people have done this work without issue. As long as there are no fuel line connection issues, you can swap them both in under an hour. I did think that if I'd just gone to the dealer in the first place that they would have been on the hook to figure out how to make the fuel line stay put, but it may have just ended with them telling me the fuel line has failed and would have directed me to buy a new tank anyway for a 9 year old vehicle way past warranty (at least that's what I'm telling myself).

 

This was so bazar I guess and frustrating for you why it wouldn't stay on. You may be right about the dealer telling you that you need a whole new tank because they will not rig anything at the dealer. So you paid the dealer $4,000 to replace the tank or did you get it from Amazon and do it yourself? You said (thanks Amazon stock)

That's an awful lot of money for a gas tank just because a connection wouldn't stay on and really sucks. It doesn't make any sense does it!

 

Im looking at oxygen sensors right now and it seams the dealer wants $600 for all 4 of them. But when I look for them at a couple other websites, they are about half the price but the part numbers are different yet they say they fit the 2013 S550. Makes no sense.

 

I bought the tank from the dealer and had the dealer install it just in case the replacement tank had an issue since I'm assuming it sat in a warehouse somewhere for the better part of nine years and I didn't want to have to jump through hoops, deal with an independent shop, etc, if problems arose. I thanked Amazon tongue-in-cheek, as I sold some stock to pay for the tank and installation.

 

I’m having the same issue after replacing my fuel filter. Ran fine. Then didn’t. So dealership recommended I replace the whole fuel tank. Do you mind sending me some pics of when you had the zip ties on it ? Or privately messaging me. I don’t got the money to do that right now so gonna roll with the zip ties for now.