Helpful Hints for Fire Apparatus and Truck Operators in Hot Weather
First of all, it is necessary to understand the cooling system. Do not expect the engine or truck to labor in low gear up long grades or through deep sand, and still keep cool if carbon deposit is permitted to accumulate in the cylinders, if insufficient water is put in the radiator, if the oil level is low or the oil is of the wrong kind. At the beginning of the season it is ordinarily necessary to change the carburetor adjustment, that in summer being a trifle leaner than that for winter. Overheating is sure to result if the carburetor is improperly adjusted.
Important Bearing of Timing on Cooling
Timing has an important bearing on cooling. In hot climates where temperatures are excessive for a considerable part of the year, the engine may be made to run cooler, but at a slight sacrifice of power, by setting the camshaft one tooth ahead (earlier) on the timing gears, so that the exhaust valves open earlier. A weak spark has the same effect as late spark timing, and overheating will result.
Difficult grades can be made with greater speed and less fuel in intermediate than if the engine is permitted to labor in high to the point of stalling. Contrary to popular supposition the engine will cool better if it is not obliged to labor excessively.
Keep the exhaust clear of obstructions and do not allow mud to cake on the outside of the muffler or to clog the outlet.
The radiator must be filled as full as possible. Do not allow the overflow pipe to become clogged, or flattened by a blow or kink or slip down the radiator.
Best Quality of Hose for Water Connections
Use only the best quality of rubber house for water connections. The inside of cheap tubing is apt to dissolve and the rubber particles clog up the system. Go over hose connections in the spring, because some antifreeze solutions have a deleterious effect upon the rubber. Also they have a scum inside the radiator which will not dissipate the heat. It must be cleaned out.
In filling the radiator only clean water should be used. Strain the water through a cloth where none but dirty water is available. Above all do not use buckets in which oil has been kept.
Keep the fan clean and well greased, so that it will turn freely.
Keep the Crankcase Clean
Not all of the cooling of the engine is effected by water; but lubricating oil plays an important part, as it cools the bearings. Keep the crankcase clean; it cools the oil. It has been found that gasoline washes the lubricant from the cylinder walls and a mixture of gasoline and oil runs into the crankcase where in time it destroys the lubricating qualities of the oil. For this reason the oil in the crankcase should be drained and replaced with new oil every 1.500 miles. If this is not done the oil will be unable to properly lubricate the rubbing surfaces and heating will result.
The average working temperature of oil in summer is higher than in winter, and so oil of the same body will be thinner. Sometimes it is advisable to use a grade heavier oil in summer. In excessively hot spells an especially heavy grade of oil may be required to maintain the oil at the proper consistency in operation. When a heavier oil is used care should be taken not to work the engine too hard before it is warmed up. Buy oil only from reliable refiners.