Radiator question

Re flow rate question. I know of no such spec. The radiator has a restriction to flow [Cv in engineering, gpm/sqrt(psid)]. The water pump builds up pressure to cause flow thru the radiator. I also saw an old radiator guy test for excessive restriction. by filling w/ water and seeing how fast it flowed out under gravity.

The 6 vs 8 water pump blades (first I read of 5) has been much discussed. As I recall, AC cars were the ones w/ 6 blades. The reason has more to do with the different pulley diameters on AC vs non-AC cars.

To clean the radiator and block, I flush out all coolant and fill w/ a water & 2 lb citric acid mix, and drive it several times for ~40 miles, then totally flush. Posts w/ before & after photos display a remarkable improvement - shiny & new inside radiator. I bought 5 lb of citric acid on ebay, or buy at food supply places.

67Dart273 makes the good point that even if the water pump works and the radiator flows well, if the fins are no longer bonded to the tubes, you won't get good cooling. I don't know if that is a known problem. Perhaps a heat gun could show a difference between tubes and fins.

Installing a lower temp T-stat will generally not help if you are over-heating. Both would be full-open at that point.