PeachParts Mercedes-Benz Forum - View Single Post

tcane · #12 02-12-2002, 07:28 PM

The W123 diesel fuel tank has a pick-up that is slightly higher than the bottom of the fuel tank. Also, the fuel tank is not flat on the bottom, but has some areas that are slightly lower than other areas - not much maybe 1/4 to 3/8 inch or so and the fuel pick-up is about 1/4 inch higher than the area immediately around it (meaning the total relief is about 3/8 to 1/2 inch). This area is sufficiently large enough to hold water that is a breeding ground for algae growth.

As you drive around corners and the excess fuel is returned to the fuel tank the fuel is mixed up and sloshed around inside the fuel tank. The wax that is in your tank will probably get mixed with the fuel as you drive and thus go through the fuel system.

Draining the fuel tank will not get all of the fuel out. The only way to completely drain the tank is to remove it. Removing the W123 fuel tank is very easy and once it is out it will be easy to drain it completely and flush out the wax by adding some diesel, slosh it around the fuel tank, and then drain it out - doing this several times should get all of the wax out.

Or, you can add a water separator instead of taking the fuel tank out. However, whether or not the water separator will catch the non-water components of the wax is unknown. Racor makes water separators for diesel fuel.

Or, you can just drive your car as others have suggested. Keeping the fuel level up will help keep the wax diluted. Also, driving around town will probably keep the wax mixed with the fuel whereas driving on the highway has the chance that the wax could run through the fuel system in higher concentrations that could cause problems.

I would think the fuel filters would catch the wax before it got to the injection pump. Changing the fuel filters a couple of times as you drive through the next 4-5 tanks would seem to catch most if not all of the wax.

My $0.02 worth!
Good Luck!!
Tom