Running Biodiesel in 1999-2006 Volkswagen TDIs
General Recommendation: We estimate that at least half our members have VW TDIs and they run well on 100% biodiesel. When the 2006 “pump deuse” engines came out there was some fear, uncertainty, and doubt surrounding their performance with biodiesel. It turned out those fears were not warranted.
Using Biodiesel in 2007+ Vehicles
There has been concern over using biodiesel in newer cars. We have been waiting to see how the 2007+ vehicles fair with biodiesel. We now have some experience and knowledge and are willing to help people safely through the process.
Engine Oil Dilution – Is it a problem? New emissions reducing technology is found in 2007.5 thru 2012 light duty diesels (for example the Volkswagens, Mercedes, Ford & Dodge trucks). It’s a Diesel Particulate Filter (DPF) and is designed to remove diesel particulate (soot) from the exhaust gas of a diesel engine. To clean/regenerate the filter, the vehicle relies upon heat to burn off accumulated soot. If the filter becomes clogged before high engine temperatures are reached, a post combustion fuel injection is introduced to aid in burning off the soot. This extra fuel can make its way past the piston rings and into the engine. This may lead to engine oil dilution, which can shorten the life of your engine. This engine oil dilution is potentially more problematic with biodiesel than diesel because it’s higher flash point prevents it from vaporizing out of the engine oil.
Study with 20% Biodiesel: No Abnormal Engine Wear Found after 240,000 miles In June 2009 the National Renewable Energy Laboratory published a study designed to quantify oil dilution and potential engine damage resulting from the use of B20 in newer cars containing DPF’s and other emissions control systems. In summary oil dilution did occur, but at the end of the trial (240,000 miles) no abnormal engine wear was found. Read all about how the tests were performed and the results by downloading the full study.
50% Biodiesel Successful Experience We are aware of at least one fleet that has been running their 2007+ trucks on 50% biodiesel since 2007. They change their oil every 2,500 miles for the first 10,000 miles, and every 5,000 miles after that. They have been getting their oil tested and have not seen oil dilution after the first 10,000 miles. Our truck has over 50,000 miles on it and no problems.