Diesel fuel is widely used for certain vehicle types, but it can gel up and cause problems in some cases. Here's why it happens and how to prevent it.

Diesel fuel gelling isn't the most common problem, due to the extreme conditions that must be met for it to occur. However, it's still dangerous for your vehicle, ...

To see how biodiesel—B5 and B100—and fryer grease compare with conventional petroleum diesel fuel, we converted a diesel-powered 2002 Volkswagen Jetta TDI so that it could operate on all three.