Methods and systems for capturing and processing audio data of a vehicle engine. In one aspect, a vehicle audio capture system includes a mobile device configured to capture vehicle engine sounds in an audio file and to associate tags identifying one or more vehicle conditions observed during audio capture and reflected in the audio file, and a server configured to process the audio file and expose an application programming interface (API) to provide access to the audio file to one or more data consumer devices. In some instances, a condition report server is configured to access the application programming interface to retrieve a version of the audio file and include data describing the audio file within a vehicle condition report. Additionally, tags may be added to the audio file based on detected engine conditions. Detection of engine conditions may be based on use of trained models.