If you used plain water instead of antifreeze in summer it has most likely resulted in scale deposition on the walls of the cooling system. In this case you should thoroughly wash the cooling system with water with anti-scale agents added. Then let the engine idle for 15-20 minutes and flush it 2-3 times with clear water.
«Buran» is a modern high-quality Mono Ethylene Glycol Tosol containing a new specially developed package of multifunctional additives. It contains a number of new anti-corrosion additives (corrosion inhibitors). Its corrosive impact on metals, rubber of gaskets and hoses not only meets the requirements of GOST (Russian standard), but also often surpasses the best foreign specimens.
Special additives prevent foaming and scale formation.
Has a high ability to resist cavitation.
Has high thermal conductivity and heat capacity, allowing quick discharge of excess heat, maintaining the working temperature of the engine.
Contains a large package of stabilizing additives to preserve endurance during use and storage.
Made in compliance with GOST 28084-89.
Originally TOSOL is colorless, dyes are only added to simplify checking the level of liquid in the reserve tank, locate leakages and to make it visually distinguishable from water; Tosol is blue according to the GOST.
Unlike water, cooling liquids don't expand when frozen and do not form solid hard substance. It forms a loose substance of water crystals surrounded by ethylene glycol. Usually forming of such a substance does not lead to mechanical damage of the radiator and doesn’t prevent the engine from start. Even after the crystallization of the whole solution it’s not dangerous, because the coefficient of volumetric expansion of Tosol is much lower than that of water. Once the engine started Tosol quickly returns to the liquid state.
The engine’s cooling system cannot be completely watertight; moreover, during the operation the liquid interacts with various materials and works in a wide range of temperatures. This results in expending of the inhibiting additives, lubricity reduction, accumulation of corrosion products, increase of foaming, and worsening of heat transfer.