Fuel Contamination Claims

The contamination of the fuel system in a contemporary gasoline or diesel-powered vehicle can cause extensive damage, vehicle down-time and significant repair costs. However, the malfunctions allegedly caused by fuel system contamination are often made without diagnostic support. 

The process of verifying an engine malfunction caused by fuel contamination is a multifaceted process that may include (but not limited to) collection and analysis of fuel samples, interrogation of the vehicle’s electronic diagnostic system, traditional mechanical diagnostics and/or physical inspection of damage components. The purpose is to establish a failure mechanism and the relationship to the vehicle fuel system. Collection and analysis of a fuel sample can identify the presence of particulate or chemical contamination through various laboratory tests but, is only part of the process.  

Chemical or particulate (rust, debris, sugar, etc.) contamination of the fuel system can be the result of an introduction of the secondary material during the fueling process, deterioration of the fuel system components or the intentional introduction during an act of vandalism. Therefore, the allegation of fuel system contamination should also include the inspection of the fuel fill area to determine the potential for unauthorized/forcible access to the fuel system. 

The sophistication of contemporary diesel-based fuel systems, which utilize the fuel for lubrication of the high-pressure pumps, are highly sensitive to fuel contamination. Diesel fuel, being hygroscopic, often has a certain amount of entrained water. Knowing this, vehicle manufacturers often install sensing systems and water removal devices to address normally occurring accumulations of water. In addition, the sensing systems of contemporary vehicles notify the operator of elevated water levels in diesel fuel and (may) create a record in the vehicles diagnostic system. However, other fuel related contaminants such as biodiesel, DEF (diesel emissions fuel) or other additives are not filtered out and are often allowed to reach the components that utilize these materials for lubrication.


Water, biodiesel, DEF and other additives often reduce the lubricating ability of the fuel resulting in irreparable damage to system components.  In gasoline engines, fuel system contamination can result in extensive damage by altering the combustion process and introducing excessive fuel to lubricant reserves. Analysis of a gasoline powered engine that is allegedly malfunctioned as a result of fuel system contamination can include laboratory analysis of an oil sample which may identify the presence (or lack thereof) of elevated fuel levels in the oil. In addition, the maintenance of the vehicle and regularity of oil service performance as it relates to the specific characteristics of the malfunction may also be determined. 

In many cases, the determination of an engine malfunction that requires replacement of the engine is often preceded by a disassembly of the engine to confirm the cause of the failure. Often times, inspection of the disassembled engine along with the after mentioned testing, establishes that an allegation of engine failure result of fuel system contamination is not substantiated. Unfortunately, fuel system contamination allegations are often (mis)used because, unlike a maintenance related mechanical failure, it may be a compensable loss. 

In summary, allegations of fuel system contamination as a causal factor in a mechanical malfunction of the gasoline or diesel engine should be addressed with a comprehensive assessment that includes not only laboratory analysis of samples of fuel collected from the vehicle, but mechanical and electronic system diagnostics potentially to include physical inspection of engine and fuel system components.The technicians at Lange Technical Services have the experience and credentials to know how and what procedures are necessary to substantiate, or contest, a malfunction claimed to be the result of fuel contamination