Kanovic

So my father in law bought a 2008 gl550 and ever since there has been a gas smell in the car. I searched around and saw mb had a lot of issues with tanks leaking etc but can’t not find that the warranty has been extended to the GL class. Today we take the rear passenger seat out and access the fuel pump and it is completely wet in top. We dry everything and realize that the locking ring was extremely loose, looks like someone has been in there before. The oring etc nothing looks bad, so we install everything and tighten it good and no leaks. We go to fill the car up and it is pissing fuel around the lock ring. I know these are issues with mb but not sure how to proceed. Should we buy all new lock ring/gasket and see what happens or could it be the fuel tank itself? Just seems like it’s not making a good seal and it is letting fuel leak when it is under pressure. Any suggestions appreciated! Thanks!

chassis

Are you willing and able to take the vehicle to an indy shop? Fuel systems are nothing to mess with, especially inside the vehicle, unless you are experienced.

Spend some time on mercedesbenzstarparts.com. There is a locking ring seal kit listed, you need to determine if these are the parts you need.

Have you used the proper tool to remove and replace the locking ring? Mercedes part number 164 589 01 07 00 prong wrench. Furthermore, 110 Nm is required on this ring nut, which may not have been achieved by those who have touched the part in the past.

WIS says nothing about using new seals when installing the fuel pump, however as good practice I would use new seals if I were doing this job.

Kanovic

my father in law is strictly diy guy so I doubt he will take it to a Indy. He has multiple cars so he has not been driving this since the smell started. We got a ring locking tool and we did tq it down but I read only to 60ft lbs.. everything seemed fine until we started to fill it up and by the time we got to the top is was leaking all around the lock ring again.

just went to that site you mentioned. It listed the locking ring seal kit but it’s for the sending unit on the driver side not the actually fuel pump seal kit.. at least accord you the pictures..

chassis

@Kanovic 110Nm is 81 ft lbs so there is a potential issue, because you torqued 25-30% too low. When I get back on EPC I will look at the sealing ring parts for the fuel pump.

Look very carefully at the ring nut and the mating feature on the tank. Is the plastic buggered or knackered? This likely means achieving a seal is not possible. Fuel tanks are like milk jugs in this regard.

Kanovic

we will try to re tq it. Thanks for the help!

Kanovic

took it apart again and no nothing look like it’s buggered or any kind of deformity. It also leaks the most after you turn the car off.

chassis

@Kanovic The parts kit is the same left (non-pump side) and right (pump side). Part no 1644700230 there are three pieces in the kit, including a ring nut. Plastic parts under load, such as these, are commonly single use pieces.

https://www.mercedesbenzstarparts.co...ket-1644700230

I would use these new parts, and torque to 110Nm using the Mercedes prong wrench.

Bart-N3GQ

This may sound redundant or ridiculous, but I suggest replacing the fuel cap with an OEM part. It's the most common problem in this area and a relatively cheap fix if it works. It may look okay, but looks deceive. Also, never fill up the gas tank beyond the first "click", and never let the fuel level go below a 1/4 tank if you want your fuel pump to have a long and prosperous life.