The Magnusson-Moss Act of 1975 specifically prohibits the voiding of a warranty by any equipment manufacturer simply because a consumer used a fuel additive. So, putting a diesel fuel additive of your choice into your new vehicle will not void its warranty. This is because even original engine manufacturers produce their own brand of fuel additives that can be a lot similar to third-party products. Additionally, producers of diesel fuel often put additives into their products to make them stand out from competition and to adhere to regulations.