I haven't actually tested it, other than the fact that it does have pressure. Once it has run for a few minutes there is definitely pressure in the system. The coolant will squirt out as soon as the cap is turned to the first notch. The radiator cap is new as well. But I find it odd that the cap is not hot, even after running the engine for an hour in rush hour traffic. The lower radiator hose is almost cold to the tough, but the top definitely gets hot. Engine temp runs great. I read in the owners manual last night that it's not uncommon for the system to loose up to 1 quart a month. Any more than that and one should be concerned. I've never heard of that before, but it's in the Ford users manual. ??????