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Fuel leak, ugh

10K views 15 replies 7 participants last post by  Kajtek1 
#1 ·
I've been having such a good time since I bought this car right before Christmas, but I have noticed some fairly poor gas mileage (@14 mpg) and the odor of gasoline when parked in the garage.

Not a super strong odor, mind you, but noticeable.

The gas mileage thing really pushed me to investigate, though I gas the smell should have first. I have been parking in the garage a couple of weeks like this, and that's always dangerous with gas vapors. Suffice to say I am parked outside tonight.

I isolated the leak to the fuel filter/pump area, under the left side of the car, in front of the rear wheel. There is a black plastic cover there with 3 nuts/bolts....I couldn't get my head under to see very clearly, even with a flashlight.

That plastic cover is moist with gasoline.

I started the car, and I could see it slowly gather into a droplet on the cover, so it is seeping from under there.

The problem is, I don't want to work under the car supported only by the jack that came with the car, and I have no other way to get under it, so now I have to take it somewhere.

I have a feeling it is a dried/cracked rubber fuel line. I found a nice video on youtube showing the same situation. Looks like an easy DIY fix if I could only get the car in the air. :(

Wonder what this is going to cost me to fix? Parts are cheap, even for an OEM fuel pump and/or fuel filter. A hose and 2 clamps is nothing. Hope they don't try to rip me off to fox this. Not going to the Mercedes dealer, as I know they would be mega expensive. The used car dealer I bought it at has a service department, so I called them and I'm supposed to bring it in to them Monday. I have no warranty with it being a 20 year old car, but I'm hoping they do the right thing and fix it for free since it was definitely leaking when I bought the car. I could smell that fuel odor the first day, but made the mistake of not getting the car checked out by an independent mechanic before I bought it. Kind of purchased it "spur of the moment". There is never a sign of a leak on the ground under the car, probably because gas evaporates quickly and the leak is only active when the car is running. Therefore, believed them when they said the car had no leaks and there was no sign of one on the ground underneath where the car was on their lot.

The joys of a 20 year old car, I guess. Still love it, though.
 
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#2 ·
This has nothing to do - yet - with the fuel filter or the bottom tank fuel screen dohicky.

The fuel filter - MB/OE Mann or Bosch is like $30 - and retail auto parts stores will have under their generic brands for less as low as $12... and as you say - for your MB two hose clamps - if the ends of the hose are split - often you can snip off 1" on the end and be in business - our you can "patch a new 6" section of new fuel hose with barbed connectors and another hose clamp - all no big deal so far cowboy..
 
#3 ·
...The problem is, I don't want to work under the car supported only by the jack that came with the car, and I have no other way to get under it, so now I have to take it somewhere...

...it was definitely leaking when I bought the car. I could smell that fuel odor the first day, but made the mistake of not getting the car checked out by an independent mechanic before I bought it. Kind of purchased it "spur of the moment". .
Invest in a set of jackstands and/or a pair of ramps and, if you really want to make things easy, a hydraulic floor jack. All of this will probably cost less than what a shop will charge you to fix this leak.

Speaking of leak, someone probably used the worm gear water line type clamps which cut into and destroy fuel lines. Get the type of hose clamps designed for fuel injection fuel hoses.

And, the lesson here is, always get a PPI, pre purchase inspection. It's cheap insurance...

Good luck,
Fred
 
#5 ·
The fuel filter and fuel pump is very easy to service. In fact the hardest part about working with the filter or pump is getting the clamp that holds the two of them, back together. It's extremely hard to get the clamp screwed in again.

Also you shouldn't really need to jack up the car to work on it. There should be enough room to put your head and arm underneath there to service it. Also you can park your car on an incline with the back of the car facing toward the top of the incline, this should give you some more room.

I will also say that using the factory jack to raise the car a little bit is fine because you won't be putting any part of your body underneath the tire and like I said earlier there is enough room to service that area without raising the car, so even if you do want to lift it using the jack, you won't be raising it enough to cause a safety hazard.
 
#6 ·
Thanks for the replies.

I thought ramps were more expensive, I see you can get a pair of Rhino Ramps for $40-50. I'd probably get a set of tire chocks too since those are only $10.

Definitely seems like the way to go here.

If it is just that short little fuel line, it would be nothing to fix.

Will I need to do it with the tank almost empty? I still have about 1/3 of a tank in there. Or does it not leak out when the car isn't running because of the pump? Never messed with something like that before.

I know a little will leak out when the line is disconnected - whatever's left in the line - but just wondering about how much I can expect.
 
#7 ·
...
Will I need to do it with the tank almost empty? I still have about 1/3 of a tank in there. Or does it not leak out when the car isn't running because of the pump? Never messed with something like that before.

I know a little will leak out when the line is disconnected - whatever's left in the line - but just wondering about how much I can expect.
Get some fuel line clamps like these
4 Piece Fluid Line Clamp Set
They will keep gas from spilling out.

Fred
 
#10 ·
Another advantage of buying the ramps and doing it yourself is that you can see if what they are telling you is accurate. I've never heard of a fuel pump leaking from a seam but I guess it's possible...

If you do really have to replace the pump, get a quality brand. You don't want the thing failing on you in the middle of nowhere because you saved $30 on the part.

Fred
 
#12 ·
Interesting bit of info. Thank you.


Bosch pumps were running about $160-190, with Pierburg and Delphi at about $140-160+.

That just seemed steep to me, though I understand that's simply what those brands cost.

I ended up getting an aftermarket brand off Amazon by the name of Autobest, that comes with a 1 year unlimited mileage warranty on the pump. It was reviewed well there and at partsgeek. I take those reviews with a grain of salt, but I digress. Their company website is informative and professional, plus their manufacturing process is ISO/TS 16949:2009 certified, which if you pay attention to such things, means quite a lot quality-wise. Decided to gamble on it.

I also bought a MAHLE fuel filter to get put on at the same time.

Even with overnight shipping, I paid about $100 total for both, so with paying the dealer $90 to install them, I'm hoping that all will be well for under $200 total. I guess we'll see.
 
#15 ·
Local used car dealer in Lexington. And supposedly gave me a break because I bought the car only 3 weeks before.

Honestly, the prices I found researching the job getting done at a shop (indy) were around $400 or more with the part.

I ended up getting it done for about $190 out of pocket, and that also included them putting on my new fuel filter along with the pump.

I supplied the filter and pump, bought online.

Could have been worse.

Could have been better too, if I was more inclined top try and do it myself, but I still would have had to buy ramps and whatnot.

It was worth it to me to just pay a little bit more like that and not do it myself in this case.

I had just replaced the blower resistor/regulator (whatever it is) a couple days before that, and that worked out fine, except I strained my shoulder working in that awkward position under the dash.

Anyway, it's done and problem is taken care of.
 
#16 ·
Fact is the last time I paid dealer on hourly bases was 15 years ago, but for programming key for W163 was min 1/2 hr or about $160 at the time.
I am pretty sure it was not more than 10 minutes for skilled technician, but they add free car wash.
The darn WC dealer at the time installed coin slot on cappuccino machine.
UNBELIEVABLE
Important part >>> azmitch got his car back on the road.
Nice weekend everyone
 
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