The cold start advance solenoid sleeve was found leaking through the wall during troubleshooting complain of a diesel engine that failed to start in cold weather. The component was revealed to be a tubular product with a “bulb” section at one end and threads on the other. The manufacturing method used to create the bulb shape was hydroforming, using a 300 series stainless steel tube in the full-hard condition. The leak was attributed to a crack in the sleeve in the radius between the bulb area and the cylindrical portion of the sleeve. Fatigue cracks initiated at multiple sites...