Partrick you might be better off using something metal or plastic. At least something unbreakable. Broken glass and soft tires could be a problem.
Also regarding the pressure test on the cooling system...When it's cold I believe you will find leaks that don't exist when things heat up. Everything will expand and tighten as the coolant gets hot.
I was siphoning some
antifreeze from a bottle and was surprised how sweet it tasted when some got in my mouth. Yes I know it's poison but I also know why dogs might like to lap it up off the garage floor. It maybe under the car until you pull the car out for a drive and then the puddle is in the open. Be careful.
John