Fungus in diesel fuel tank

[Brian Willetts]

Fungus in diesel tank 

[Hybrid21]

Sounds nasty?

[Cyker]

Fungus or just microbes? They can start to grow if the tank is is run partially filled a lot and the car is sat a lot as condensation gets into the tank and you get a water layer.

It's one of the reasons I was told why it was a good idea to fill the tank in my old diesels rather than always half-fill it.

If it gets bad enough will clog the fuel filter or the pickup-strainer, but once those are replaced/cleaned and the worst of it is removed things should be okay again.

Worst cases need the tank drained and removed for a serious power-washing, but this is rare and usually requires extreme neglect.