Bob the laser pointed thermometer like you have is exactly what is needed to find and pin point heat problems. Your readings are right in the ideal range. I have several and just bought another brand new Raytec laser thermometer still in the box on ebay last week for $12.00. You also took the readings in the only really important temperature spot on the engine. You can also use it to pin point hot spots such as brakes and other places subject to heat. On the 32 to 36 engines on the water pump outets, the 37 to 48s, the metal just below the radiator hose at the center of the head and the 49 to 53s on the goose neck. I would say hold the gun about 12 to 14"s away at the same angle and hit the close to the same spot each time you take a reading. The reading can vary if not taken as described above. For the few that may not know it the water jackets on both sides are not connectected in the engine so you need the temperature of each side. The radiator temperature is both sides mixed. Both sides should be within a few degrees of each other. With 180 stats down here in 85 degree outside temperatures I see 178 to 182 every time I check it. Now keep in mind thermostats have NOTHING to do with cooling an engine, only heating it and keeping it at the thermostat rateing. In this case we are talking 180 degrees. If it's cooler outside the stats will stay closed and open when the water in the engine gets to 180 the stat opens. The stats will close when cooler air through the radiator cools the water going back through the engine and open as the water heats back up. I put a digital dash in my old GMC motor home which were 160s. One cool night going through the hills of Va. The heater would put out cold air going down hill and warm air going up hill as more power heated the engine more. Once the stat opens in hot weather there is no cold air to cool the water and close the stat, it just stays open and won't close until the water temperature drops below 180. It won't drop below 180 in towns or stop and go traffic it just keeps going up. The hotter the outside temperature the the higher it go's. With a good cooling system it shouldn't go much over 200 and as soon as you get moveing 30 MPH or more for a 1/2 mile the water temp should come back down to the 180 stat temp. The forced air through the radiator from forward motion is what cools it once moveing. Going into a head wind will cool faster than with a tail wind even though it takes more power to "fight" the wind. The poor stock fan blades and the way air is directed through the radiator is why it heated in traffic. A better fan blade will help some and a better blade with a shroud will completely solve the temperature rise in traffic. I have this set up along with Skips pumps in a 39 pick up and it never gets over 180 in traffic and comes back to 170 with no stats on hot days. If I had stats in this truck it would pretty much stay glued on 180 all the time. G.M.
