Will Insurance Cover DEF in Diesel Tank?


Diesel Tank Exhaust Fluid (DEF) plays a crucial role in modern diesel engines by reducing harmful emissions and meeting emission standards. However, accidents can happen, and there may be instances where DEF accidentally finds its way into thetank. This raises the question: will insurance cover DEF in a diesel tank?

Understanding Diesel Exhaust Fluid (DEF) And Diesel Tank

DEF is a non-toxic solution made of urea and deionized water.And it is injected into the exhaust stream of diesel engines to convert harmful nitrogen oxides (NOx) into harmless nitrogen and water vapor. It is stored in a separate DEF tank and should never be mixed with diesel fuel.

The Consequences of DEF Contamination in Diesel Tank
If DEF gets accidentally added to the diesel, it can cause various problems. Diesel engines are not designed to run on DEF, and the presence of DEF in the fuel system can lead to engine malfunction. Reduced performance, and potential damage to engine components.

Insurance Coverage for DEF Contamination
Whether insurance will cover DEF contamination in the diesel tank depends on the specific terms and conditions of the insurance policy. In many cases, standard auto insurance policies may not explicitly cover this type of incident. However, some insurance providers offer additional coverage options that may include misfueling or wrong fuel contingency.

Misfueling Coverage
Misfueling coverage, also known as wrong fuel contingency or misfuelling insurance, is an optional add-on to some auto insurance policies. This coverage is designed to protect against damage resulting from accidentally filling the fuel tank with the wrong type of fuel. Such as adding DEF to a diesel tank.

Determining Coverage Eligibility
If you have misfueling coverage as part of your insurance policy, you may be eligible for compensation if DEF contamination occurs. However, it’s essential to review the policy’s terms and conditions to understand the extent of coverage. Any deductibles, and the claims process.

Filing an Insurance Claim
If your vehicle experiences DEF contamination. The first step is to contact your insurance provider and inform them about the incident. They will guide you through the claims process and may request supporting documents. Such as receipts or evidence of the misfueling.

Preventing DEF Contamination And Diesel Tank

Preventing DEF contamination in the diesel is crucial. Here are some preventive measures to follow:

  • Education: Ensure all drivers and vehicle operators are aware of DEF and its purpose. Emphasizing the importance of keeping it separate from diesel fuel.
  • Proper Labeling: Clearly label DEF tanks and diesel tanks to avoid confusion and misfueling incidents.
  • Safe Handling: Use appropriate equipment and measures to fill the DEF tank carefully, minimizing the risk of spillage or cross-contamination.
  • Inspections: Regularly inspect vehicles to ensure the DEF and diesel tanks are in good condition and properly maintained.


Accidentally adding DEF to a diesel can have detrimental effects on a diesel engine’s performance and longevity. While standard auto insurance policies may not cover such incidents, misfueling coverage can offer protection and financial assistance in case of DEF contamination. To ensure coverage eligibility, it’s crucial to review your insurance policy. Consider adding misfueling coverage if available, and take preventive measures to avoid DEF contamination in the first place.

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