Inspection Methods

Flashlight: Shine a strong light on one side of the suspected leak area and look for light on the other side.

Water spray: Use a shower head or sprinkler head to spray water along the suspected leak area. DO NOT USE HIGH PRESSURE WATER (25 PSI maximum). Wait until the leaks begin, and mark the leaks. Spray talcum powder on the dry side of the leak area to make the leaks more traceable.

Water flow: This test is useful for pinpointing a leak first detected with the water spray test. Direct a flow of water from an open hose to the lowest point of the suspected leak area. Slowly move the hose upwards until the leak is detected. DO NOT USE HIGH PRESSURE WATER (25 PSI maximum).

Soap bubble test: Mix 1 part liquid dishwashing soap and 3 parts water in a spray bottle. Spray the mixture onto the inside of the suspected leak area. Use a blow gun to blow air along the suspected leak area. Use high pressure air for metal to metal weld seams and low pressure (15-30 psi) for testing rubber seals. The soap will form large bubbles in the leak areas. Along glass runs and door seals, small bubbles will form when too high an air pressure is used, and large bubbles will form at potential leak points.

Soap bubble test with a pressurized car: Close all of the doors and windows, turn on the ignition key (engine off) and set the blower fan to high in the fresh air mode. This will pressurize the interior of the vehicle. Spray the dish soap and water solution onto the vehicle exterior over the suspected leak areas. The soap will form large bubbles where it leaks out. This test can also be used to locate wind leak locations.

Tracing powder: To determine if a seal has consistent contact, spray tracing powder (Kent Industries "Tracing Powder" or 3M "Leak Detection Powder") onto the metal panel, then shut the panel. The powder should transfer to the seal where the seal has adequate contact.

Ultra sound leak detectors: Place the transmitter in the vehicle and follow along the suspected seam with the detector. Follow the equipment manufacturer's instructions.