Why does sludge still appear in the oil pan?

Sludge refers to the fuel residue inside the engine. Also known as carbon sludge, it remains in the engine oil and is filtered by the oil filter. However, if the engine oil or oil filter is not changed, sludge will accumulate and the engine oil will become dirty and deteriorate. If the oil is black, it is very likely caused by sludge, so the oil needs to be changed.

First of all, is this sludge normal? It should be abnormal. Many people also explain that this greasiness is normal and is present in every engine. This statement is wrong. Engine oil is pumped to all parts of the engine by the oil pump through the filter screen, and then returns to the oil filter element from top to bottom. The impurities flow to the oil pan after being filtered. This kind of sludge can be said to be several times the viscosity of the oil product and basically lacks the performance of a fluid. It will firmly adhere to the surface of the oil pump filter screen. If the filter cannot effectively draw in sufficient oil, it will affect the oil circulation performance, accelerate the deterioration of the oil, and cause more and more sludge to accumulate. Engine oil has a cooling function in the engine. Insufficient flow leads to local high temperatures of the engine oil, which is the fundamental cause of sludge formation.

Residues will be left inside the oil filter element during the oil circulation process. If the oil circulation is normal, the sludge should be in the oil filter element instead of adhering to the surface of the oil pump filter screen. Then the oil is changed every time. Why is it still like this? Turbocharged engines can use low-viscosity engine oil, but for ordinary engines, it is necessary to replace the correct type of engine oil. Sludge is not caused by engine oil problems. Of course, fake engine oil is another matter.

Residues will be left inside the oil filter element during the oil circulation process. If the oil circulation is normal, the sludge should be in the oil filter element instead of adhering to the surface of the oil pump filter screen. Then the oil is changed every time. Why is it still like this? Turbocharged engines can use low-viscosity engine oil, but for ordinary engines, it is necessary to replace the correct type of engine oil. Sludge is not caused by engine oil problems. Of course, fake engine oil is another matter.