The knocking in a car engine has different reasons. Some of them are serious and will lead to engine failure, others are associated with minor defects and can be eliminated literally on the fly by the car owner. When an engine fails, it is better to immediately contact a company that accepts scrap metal
and deals with heavy machinery removal. In any case, occurrence of extraneous sounds is a reason to find out their reason without delay. The engine is a heart of the automobile. If you start the situation, it may cause a serious damage, the removal of which will require a lot of time, n
erves and money.
If you noticed a knock in the crankshaft, then there could be an increased gap in the bearings (main or crank bearings) due to the wear of the crankshaft pins or shells. The normal value is 0,02-0,04 mm.
Other causes of crankshaft noises:
An old oil filter that is clogged. The result is the opening of the bypass channel for the oil supply and possible ingress of foreign particles along with it into the bearing.
Poor oil quality.
Low oil flow to the bearings due to a defective oil pump, clogged filter or oil channel. These problems cause the light on the panel to light up, so you’ll know right away when they occur.
Uneven surfaces and scratches on the shaft journals after repair work or improper storage.
The oval shape of the necks of the new shaft supplied to replace the old one. When purchasing with a micrometer, measure to be sure of the quality of the product.Tosol or water in the oil.
Motor runs without oil, which happens when starting cold.
A knock in the camshaft happens due to the same factors. It is a muffled extraneous knock when the vehicle starts cold. The sound goes away 1 to 2 seconds after the oil is applied. If you do not take care of the elimination of the defect in the near future, the wear of the elements will result in the appearance of a knock during the startup or operation of the insufficiently warmed up engine.
Generally speaking, knocking is a common occurrence with early ignition on a gasoline engine and early injection on a diesel. In one case the fingers knock, in the other there is “hard running”.
Engines equipped with hydro-compensators knock due to low oil flow or increased clearances. The sound is audible and is of the same frequency as the crankshaft.
Diesel engines sometimes have a knock at the fuel pump or piston due to improper timing.
Sometimes the piston knocks on the cylinder head. This is due to a too thin gasket under the head.