You might be amazed at just how much crud can build up inside an old diesel fuel tank. If the car has only been running diesel fuel, much of what you might see is caused by algae growing in the tank. Over time it will turn into black colored particles that will start showing up in your clear plastic pre-filter. If the car has been running biodiesel or SVO the problem can be even worse.
Problem & Solution
Common among these chassis:
Check out Kent's YouTube video on what he found was the problem with a persistent power loss problem on a 300SDL.
If the problem is slight you may be able to drain the tank and flush it with clean diesel fuel. If the build up is bad enough you will have to remove the fuel tank and have it cleaned or replace it with a good used fuel tank. The tools, parts and supplies you will need to accomplish this are listed below
To learn how to remove and replace the tank yourself see Kent's Fuel Tank Removal video..