The paper presents the results of a study on the influence of seasonal conditions on the reliability of diesel and gas diesel vehicles. During the experiment were treated with statistical data on the failure of the two groups of trucks, methane-diesel and diesel operated under the same conditions. As a result of analysis found seasonal variations in the flow of failures between the two groups. Then the failures were divided into failures of components and assemblies cars such as engine, transmission gear and chassis of cars. This division has revealed the influence of seasonal conditions on the reliability of components and assemblies of diesel and gas diesel cars and their differences. Studies have shown the need for adjustment of norm in the planning of maintenance and procurement of spare parts for gas diesel vehicles.
Keywords: Stream failure, gas equipment, seasonal conditions, the reliability of vehicles, maintenance and repair