Coolant capacity?

22 quarts is what you want in the system not 16 or 18 as most people think. With a good WORKING 4 lb pressure cap and no compression leaks the coolant will stay right up in the neck as long as the temperture don't get much over 200. I just drove my 39 convertible from SW Florida. Left Weds morning at 6 AM arrived at the Ford meet in Charlotte NC before dark. It was between 98 and 110 the entire 640 mile trip. Engine temperature at 65 to 70 MPH was 185 and a little less at slower speeds. Checked the water Thurday morning and a little came out over the top of the neck. Left Sat morning and came up to Pa and it was 95 to 105 plus all the way. Just ran down and removed the cap and coolant still came out over the neck. With the coolant filled there is no air in the system and no foaming, pure coolant cools better then coolant mixed with air. Got stuck in a 5 to 8 mile traffic jamb for about 15 minutes of no or very little forward movement at 105 degrees, the temperature went up almost to the top so I went up the right shoulder and someone let me in and we started moving slowly and it went down to 185 in less then a mile. even going slowly up the shoulder the temperature started comming down. I have tap water, 2 gallons of Prestone, 2 bottles of water wetter and a large bottle of heavy duty Barrs aluminum granular stop leak. I changed the coolant before I left and wanted to try water weter. More coolant equals better cooling, more water circulated by Skips pumps also equal better cooling. I did take my pen knife before I left and carved out a cardboard plate for over the opening above the grill and back to the radiator. The hood held it in place. I knew at these temperatures for 2 straight long driving days even a 2 or 3% increase in air would help. I did pick up a bunch of fine black dirt in the gas but that's another story which was a big pain in the A. It's a good thing I'm used to hot weather. It was comfortable in the car when it was moving. When the engine runs fairly cool in hot weather you don't get a lot of floor and firewall heat in the car. The hood also don't get as hot so cooler air comes in the vent. The engine oil also don't get black when it runs cooler. Others on these forums have questioned that over the years so when John Mason came by I had to show him the oil which was a medium to dark yellow. These engines also use less oil when cooler. I used a 1/2 quart on the 640 mile leg, haven't checked it today from the final leg which was 520 miles. I now have over 105,000 miles on this engine in 30 years. G.M.
 
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