I'm getting a little ahead of myself here and/or asking a stupid question, but I'm wondering if a coolant system can be pressure tested without filling it with coolant? I'm in the process of replacing all of the coolant hoses (2 leaks in as many months has me paranoid) and, while I thought I had a bad heater core, I may have been mistaken (see https://forum.ih8mud.com/showthread.php?t=85510). Before I install the new core that I bought, I'd like to try to pressure test the system with the old core and see if it holds pressure. This would (assuming CDan allows returns) save me a couple hundred bucks. Also, and I KNOW this is a dumb question, does the petcock on the radiator have to be turned multiple times to get it to open or is it a simple 90-degree turn to open? I'd experiment on mine, but the system is currently draining into a bucket from the radiator hose that I disconnected when I couldn't get the petcock to drain and was in a big hurry.
