[Dick M]

You must have a clean cooling system. If you see evidence of rust in your water it must be eliminated. I have found the best way to clean the system is to drain it and refill with kerosene. I know it sounds crazy, but it works. I learned this trick from an old time Model Aer. He said during WWII anti-freeze was unavailable. He lived in Nebraska. He further told me they filled radiators of the farm equipment and autos in the winter with Kerosene to prevent freezing. The side benefit was a completely clean cooling system. I tried this on my Model A, drove it for about 3weeks, and the result was a very clean system. It is important to be sure after driving around with the kerosene in the system the radiator and block are flushed until clean. You may have to have the radiator boiled out at a shop to get it clean. I live in an area where we don't get too many days below freezing. I use spring water (crystal geyser) and two bottles of "water wetter" in my cooling system. You can purchase water wetter at any parts store. I do not accumulate any rust as water wetter has a rust inhibitor. Further, anti- freeze boils at about 240 degrees which I do not see as an advantage. Water has better cooling properties than anti-freeze and therefore it cools your engine more efficiently. I change the water in the system at the beginning of each driving season. Our summer days are 95+degrees and my car never runs over 180 degrees unless climbing a long hill in which case it can climb to 190 degreees. JMO