Ford NAA, Ford 2810, Ford 3910-1, Ford 3910-2, Ford 4600SU, Massey 2660 HD, Massey 461, Grasshopper 725D, Grasshopper 900D
This is my fuel cap on my 3910. What is the stuff on the cap? Looks like rust? Maybe it is but how would rust form with diesel fuel? The entire tank is lined with it and fuel shut off valve keeps getting clogged up with small particulate. Fuel is orange color too.
It's rust, most likely from condensation, I think Ford had a problem with this on some diesel super duties. You would not think it could happen. But diesel fuel is not engine oil.