My 2003 SL55 has developed a rattle. You can hear it inside the car but you can only hear it outside if you open the gas cap. Has anyone had this problem? I'm guessing the tube going to the tank broke off. Any other ideas? Thanks for your feedback.

 

What does it sound like? If it sounds like a Chinese gong then it's the tank baffle and you have to either replace the tank or "fix" it. If this is the case I could give details about how to do it.

 

It's a flapping noise. Like a loose mud flap on a truck. And no, I don't have mud flaps. LOL It's like something is floating in the tank and banging on the sides.

 

Some additional info. I hear it when I stop or start. No noise when running down the highway.

 

It sounds like it's the baffle that came off. Can you hear it when the tank is full?

It appears to be a common problem that I ran into as well. There are a few things you can do:
1. Always drive with a full tank
2. Have the tank replaced
3. Take the tank out and have it fixed
4. Fix it yourself

I opted for #4. Are you comfortable taking your car apart?

 

I noticed it after I filled up and then got down to 3/4 tank. I'd shoot for #4 if you have instructions. - Thanks

 

Yeah, that sounds about right. I have instructions on how to fix this but when I was doing it I didn't take any pictures.

What you need to do is take the middle lining in the trunk off. Start by taking off the roof cover lid, it has screws below the plastic covers (take those off first). Take the plastic net hooks off next, then the plastic holder where the roof cover lid clips on. You can now pull the middle lining off. This should give you access to a hole about 3 inches in diameter. This is the fuel gauge sending unit. You need to pull it out. First, disconnect the wires. The way I did that is I made a tool from a thin piece of wood with two screws drilled through. The screws should match the holes on the sending unit. Fit the screws in the holes and turn the whole thing counter clock wise. Once loose, pull the sending unit out. Now, get a flashlight, break a plastic hanger so that it hooks at the end. Stick it through the hole in the tank and push on the metal piece at the front of the tank. That is the baffle, check if it is loose. If it is, continue, otherwise, you have a different problem .

Look at the sending unit. Drill a 1mm hole where the unit leg bends. Stick a stainless ring through the hole facing the front of the tank. Measure approximately how much distance between sending unit leg and the baffle. Go to the hardware store and buy a spring that is a little shorter than the distance between the leg and the baffle. Attach one side to the ring on the sending unit, make sure it's the side that will not slide off because it's a pain to get things out of the tank through that hole if something falls in (I know this from experience). Slide the sending unit and the spring down the hole. Use something long enough to pull the spring hook behind the baffle. Once secure, push the sending unit down the hole and close it up.

I've been driving with this fix for a few months and it's holding up perfectly.

 

Thanks!! I'll let you know if it works.

 

Never heard anyone approach it like this... Wish i could visualize what you did..
Nick

 

How long did the fix take for you to do?

 

It's the baffles in your tank. My 2002 SL55 had the same problem, they have to drop the rear suspension to change it, mega bucks, so I put it in part ex
for a 63. Old Merc's without warranty is like a time bomb strapped to your
wallet.

 

All together, including the trip to the hardware store, about 2 hours. The hardest part is figuring out what to do about it.

 

I do not understand that sentence. What did you do?

 

It looks kinda like this:

 

Sorry, I meant that in order to fit a new tank they have to drop the rear suspension, expensive job.

 

I see. Yes, it is around $4K at the dealer from what I hear.

 

Replacing the tank fixed my2003 right up !

The spring band-aid is an interesting cure ! Kinda like toyota modding the gas pedals if you know what I mean

Did you talk to Ken from Renntech about it ??

Marc

 

What was the cost of your tank replacement? What can Ken from Renntech do for me? Thanks.

 

Mine was covered by my extended warranty so $100.00 the tank was like $2100 if I remember and then the labor was like $1500. No I was talking to ken and he asked me about it. then I saw your post so I was wondering if that was you. Maybe he knows a good source to get it done for less.

 

$4,000 is about right. I had a tank replaced on my 03 last year. I don't recall the exact cost because my warranty covered the lions share. Paid for the warranty in one trip to the stealer.

azbenzguy, good luck with the repair. it almost seems like this issue should have been a recall item.

 

I unfortunately have the same problem now... fuel tank baffle -That's the last draw with my 2003. Shes been fun (60k miles)but time to part ways. Costing a fortune in repairs and I have a BS warranty company (AutoSource of america) that doesn't pay for anything. Now I Have to decide where to go next ... 63 or Porsche?? I was trying to wait because I would hate to by a 63 now and then the new shape comes out next year or whenever and kills the value. Decisions decisions

 

Hey you do not have to drop any suspension to remove the petrol tank it is a big job but it will come out from inside the car from behind the seats once you have removed a lot of stuff, I had mine removed because of the baffle in the tank and now it is going to be removed again as the petrol pump is going to pack up.This car is very costly,rear pneumatic suspension, Vacuum pump in boot,centrifugal water pump, air pump that is apart from the petrol tank and he petrol pump who knows what will be next, this is all in the last hree years all of his for a bit of fun .

 

Has anyone else had success with this mod ? Does anyone had a pdf on what is removed in order to access the sending unit ?

Thanks all

 

So I took the advice of Super_monkey and went after the noise in the fuel tank..and what a pain in the *** that was!!! Getting to it and diagnosing that the issue was the fuel baffle (piece of ****), was very easy as described. However, fixing it was slightly more difficult. Lots of thinking out of the box. Anyways, used coat hanger and spring to attach to baffle and fuel sending unit. Ran into snags by misplacing the spring part on the sending unit, but finally figured that you must place hole in the dark gray area near the top so not to interfere with the float mechanism. Otherwise, it disables the float and screws with the fuel level gauge. After a few hours of messing around and making sure not to drop anything in the tank, all is good. Works fine and hopefully I'll never have an issue again. If so, maybe the next step is a new tank all together. Shame benz never recalled this issue, but seeing the posts on how to fix the problem, I know why they chose not to!! Anyways, if anyone has questions, just post a reply and I'll call or email you instructions. Cost me $3.49 for the fix and some time. Better than $4000!!! Peace.

 

Please describe the spring dimensions and is it stainless steel ?

Many thanks for the reinsurance