Is the the dreaded diesel bug?

[Rob]

Have not changed it since Mongolia, was expecting it to be much worse TBH. One thing concerns me is the brown goo, is this the diesel bug?

 

[sae70]

It does not look good! Does it smell of rotton eggs? I've only had experience of this on boats, it comes from a bacteria that lives in the Diesel that is encouraged to breed when it interacts with water. I'm sure that you can get a test kit for about £20/25 and if it's positive chuck a Diesel Biocide into the tank, I think I remember one of the motor cruisers in the marina had it bad and had to have a firm in to pump out all the fuel (1000+Ltrs), clean the system new filters etc. they then cleaned and treated the fuel and pumped it back in, not great

 

[Rob]

I have already thrown it in the the wheely bin, not sure I want to dig it out just to see if it smells of rotten eggs. I will be replacing the water sensor soon though so will get to see if there is any more.