Contaminated Fuel: What to do
If your vehicle is stuck in the shop because the mechanic claims you need a costly repair as the result of contaminated fuel, immediately start on this list. If it is a diesel engine you probably need legal advice as soon as possible.
Preserve the EvidenceMost important of all: Preserve a fuel sample. A mason jar with a seal or some approved container is a good storage vessel for a sample. This will become important at a later time if there is a contest as to whether the fuel is actually contaminated. Secondly, save the parts that show the contamination and take good photographs. You also probably want to engage a skilled inspection to note his observations as soon as possible.
Determine who could be responsible to pay for the repairMake claims to the potentially responsible parties. If you have remaining factory warranty you need to contact the manufacturer for a warranty repair. If you have an extended warranty policy, appeal to them. If you know where you bought the fuel, contact the fuel provider. If you have comprehensive insurance, make a claim. True fuel contamination is often covered by your insurance policies. Make all of these claims IN WRITING and deliver to the respective responsible party with a means to prove they received the notice.