If it's not boiling, it's not overheating. However, rust and crud can accumulate at the bottom of the water jacket, and it tends to get thicker toward the back of the engine. Greasy deposits can be removed with TSP (Trisodium Phosphate), the stuff that's used to clean concrete floors. Use about a cup of the powder with a fresh fill of clean water, and run the engine for 30 minutes or more at a fast idle. Then drain and flush several times with clean water. Rusty deposits need a different treatment- - - - -muriatic acid (technical grade hydrochloric) that's used to clean up after masonry work. 4-6 ounces of the acid- - - -fill with water, and run for 30 minutes. Then flush with a mixture of water and a box of baking soda to neutralize the acid. Both chemicals can be purchased at any big box hardware store. Finally, use a 50/50 mix of water and antifreeze.
Jerry
