My 97 Cavalier has had a slow coolant leak lately, which I discovered a couple weeks ago when the engine started overheating and I found the coolant tank empty. I refilled it with water and it’s only lost a couple inches from the top since then.
So I borrowed a Motorad pressure tester to see where the leak is coming from, and the only source I could see was from the cap. It feels like I was able to get the tester onto the coolant tank pretty securely, and pressure does build a little bit before starting to leak, but I suspect maybe I’m just not get the tester secured as well as I’d hope. Could a faulty cap really be a likely source of the coolant leak?