You could also use an ultrasonic leak detector to find the tiniest leaks. It looks for the ultrasonic noise from any gas under pressure or vacuum escaping from a small hole. https://www.youtube.com/watch?v=bScWauDBQ9Y It also has many other uses in the garage. Air compressor leaks, tire leaks, vacuum leaks, fuel injector pulsing, worn bearings. If you have the accessory ultrasonic transmitter, then you can check window and trunk seals.
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