Replacing the fuel filter on your Volkswagen TDI is one of the simplest maintenance items you can do, but it is also one of the most crucial. Dr. Dan of Dr. Dan’s Biodiesel explains how a clogged fuel filter can cause a multitude of symptoms, ranging from simple low power and hard starting to more deceptive ones such as limp modes, check engine lights, turbo malfunctions, and more. Often these are mis-diagnosed as much more serious problems when all that is needed is a fuel filter replacement. Prolonged operation with a plugged filter can also lead to much more serious and expensive problems. Dr. Dan discusses diagnosis, diesel fuel quality issues and recommended sources, and takes us through the procedure of replacing a fuel filter on a TDI vehicle.