[G.M.]

Tom I mentioned above how a pressure cap works to keep all of the water in the system. It is NOT used to raise the boiling point of water, that is not a factor with these engines in the stock configuration it is used to keep all of the water in the system. The other feature of the cap I failed to mention is that it also functions as a safty valve. The 7 lb cap isn't in a dangerious pressure range but I prefer a lower range of protection. The higher the pressure the more damage it can cause to people and components. If my pressure gets over 4 lbs I want it released into the air rather then blow a hose, split a radiator seam or blow hot steamy water on me or someone else. I would say the water temperature would have to get in the 210 or a little higher to open a 4 lb pressure cap. If the temperature gets this high there is a problem and the pressure should be released before damage occurs. If I'm driving and it's 95 to 100 or more and I get stuck in stand still traffic I get out of there or pull over and wait until it cools or get moving when It gets near 200 degrees. In less than a mile when I get moving the temperature will drop back in the 180 range. I was driving my 39 in June on I-95, the temperature was over 105 outside and I got stuck in a 8 or 10 mile traffic jam with very little movement. When it got over 200 I went up the shoulder lane looking for a place to get off. Moving even at a very slow speed the temperature dropped very slightly and I got up to where the traffic was moving and someone let me in and in a mile or so the temperature was back to 185. I don't promote going up the shoulder but I did it with caution and didn't have much of a choice and figured with the old car people don't get hostle and a cop may understand the problem. G.M.