You can use liquid detectors to pinpoint leak spots. Engage all of your senses while at it–look for oil, listen for leaks. If you see oil, spray soap bubbles on the suspected spot. Finding small bubble leaks, especially really tiny ones is a skill that requires a lot of patience to acquire but pays off immensely in terms of quality of work and reduced leak recurrence or callbacks. There are a lot of online videos on our website or YouTube channel to help you reach mastery. Check it out today! ht