What Causes White Oxidation Spots on Engine Blocks?
2 Answers
Engine block white oxidation spots are caused by: the engine being an aluminum alloy engine or the engine coming into contact with coolant, battery acid, or water. Precautions for engine maintenance are as follows: 1. Fuel must be clean: High impurity content in fuel can accelerate the wear of the electric fuel pump, reducing its service life. Unclean fuel can also lead to clogging of the fuel filter and fuel injectors, affecting fuel supply pressure and normal fuel injection volume, thereby diminishing engine performance. 2. Correct fuel selection: Engines have high requirements for fuel quality and grade, with fuel-injected engines having even higher demands. For vehicles equipped with catalytic converters and oxygen sensors, only unleaded high-octane gasoline should be used. If leaded gasoline is used, the exhaust catalytic converter will fail after driving more than 400 kilometers, the oxygen sensor will malfunction, and the normal operation of the engine will be affected.
I encountered a similar issue last time. The white spots on the engine block are mainly caused by coolant. When antifreeze leaks onto the block surface, especially on aluminum blocks, the ethylene glycol inside decomposes under high temperatures to form acidic substances, which corrode the metal surface over time, resulting in white frost. Additionally, residual alkaline car wash detergent left uncleaned during engine washing, or long-term driving in humid coastal areas where salt and moisture interact, can also cause this. I recommend having the mechanic check the water channels and joint seals during every maintenance session. After all, this type of corrosion can spread gradually, and if it leads to block cracking, it becomes a major problem. If addressed promptly, simply sanding the area and applying some anti-corrosion coating can resolve it.
