Product Recommendation for Cleaning Tank Strainer
 

I have reason to believe that I may have a fuel restriction at the tank strainer on my 91 300D (both fuel filters have been replaced). As that part of the fuel system has, to the best of knowledge, never been touched, it seems like it would make sense to replace the strainer just on principle...have one on order.

But, before doing that, would it make sense to try an additive to dissolve whatever is clogging the strainer? If so, what product might be well-suited? I'm looking at the various Star Brite products...not sure which if any would be a good choice.

Thanks for any help.

If the sending unit is accessible on this like a W123 i.e., under the first aid box consider pulling it and try to look down into the tank before doing anything.

As far as an effective clean up product, sorry I don't know of any if the strainer is clogged. If the strainer is clogged there is likely more in the tank. I would use BioBor to kill anything in the tank before working on it much.

Good luck!!!

In Tank Strainer Cleaning
 

To do the job properly it needs to be removed .

Before you do this drain the tank fully .

I'm still using the most excellent purple cleaner / degreaser from Sam's Club Rich hipped us to some time back, it co$t$ $6 the gallon, I cut it 50/50 with tap water and it's amazing how clean it gets things .

Startron is really good stuff -BUT- it takes a while, multiple doses before everything is dissolved and gone .

Bio-Bor or Diesel 911 work well and very quickly but they'll also clog you secondary filter with dead fungus .

Choose how you address this carefully and wisely .

IIRC you can pull the tank strainer from the bottom but it will take some contortion.

Plain old soap and water is the best cleaner I've seen so far. It restored a pre filter I had to like-new lol!

IIRC you can pull the tank strainer from the bottom but it will take some contortion.

Plain old soap and water is the best cleaner I've seen so far. It restored a pre filter I had to like-new lol!

Whatever you got. I like ammonia but as said, the Sam' cleaner is good and Ivory dish detergent works fine too.

If you use ammonia you can also wash your clothes in it because you're going to drown yourself with diesel when you pull that screen. The best you can do is empty the tank but even with the right side of the car on jackstands and gravity moving all the fuel to the drain point you're still going to have diesel running down the arm you use to unscrew that screen unit.

To clean that strainer, plain soap and hot water is required, you will need a new O ring to seal it though - its a large size and available at almost any parts shop with a counter (not hanging on the display shelves)

There would be quite a lot of crud surrounding it in the tank right under the inverted bowl the strainer sits in - dont jam your finger to scrape it off, use a coat hanger fashioned into a tool to move that trash to the opening and let it fall out.

Otherwise, removing the tank is a 10 minute job on a W124 (wear gloves as some parts are sharp back there)

Well OP, should you choose to install your new strainer, and then for whatever reason, clean the original, the methods above will likely work.

To answer your question, however, "Power Service 09016-09 Bio Kleen Diesel Fuel Biocide" (that's the amazon search string) is fairly potent. In theory, it should dissolve whatever's in there, allowing it to pass harmlessly through filtration. In theory.

Worth a shot.

In Tank Strainer Cleaning
 

You don't need any hot water, just a good strong de greaser and a soft tooth brush .

This is one of those dirty P.I.A. jobs that should be done every time you buy an old Mercedes .

Cleaning it makes more sense than replacing, and you don't need to run any magic juice through the tank. It's not hard to remove. The tank needs to be drained, but it doesn't have to come out. Lift the car, and look up beside the left rear wheel. You'll se a rubber seal with a few lines running through it. Pull the rubber down, and you'll see the tank connection. The rubber hose screws into the strainer. Undo the hose, then a big socket is all you need to remove the filter. It can be washed with dishwashing liquid and replaced. Just let it dry before you put it back, and use an new o-ring if the old one is deteriorated.

Being that it is a w124, just how do you remove the fuel sender? The first aid box is in the center of the rear deck on the sedan.

W124 Fuel Gauge Sender
 

I don't know but, have you yet tried removing the first aid kit tray ? .

the way I tackle the fuel sender is to remove the tank, 4 bolts in the trunk after you pop the carpet pad off and two hoses under the car (make sure tank is low otherwise have lots of fuel cans and get a siphon going to save the fuel)

The sender takes the same 46mm socket/wrench as the strainer. Its canted towards the back of the tank so some wiggling after you clear the threads would be required to finagle it out.