Fault: crankshaft bearing alloy suddenly fall off.
Reasons: ( 1 ) cylinder pad is washed, flooded metamorphic engine oil, not replace cylinder head gasket and oil in a timely manner, instead of full load, or even overload, forced running, 1^-3 day is prone to main shaft tile falling off.
( 2 ) the oil long time in dangerous case ( oil foot lower lattice ), not timely replenishment of oil, the main bearing is not caused by lubrication, bearing off.
( 3 ) the oil less, and particularly dirty, not only did not change in time, but also long time speeding, but also prone to this fault.
( 4 ) starting in the winter after the car, immediately forced off ( the oil temperature rose to 80`C, the oil of each parts are compared with full lubrication and then start ), start forcibly speeding, lubricating oil and dirty, easy to cause the main bearing shells falling.
( 5 ) the engine to a set of main bearing oil passage blockage. There are 3 bolts on one side of the main oil generator lubricating oil 492Q series engine, to the spindle of three sets of oil bearing, the other to the main bearing shells, in the oil filter. The oil channel depth of engine cylinder 1/2.
Horizontal oil to the main bearing is smooth, use wire probe, but that a vertical oil is directly communicated with the main bearing road, need to remove the bearing, to check whether the plug.
Oil passages are often caused by a single set of main bearing alloy break off. But if not found in time, dredge the blocked point, but only for bush, soon after the new bearing is put into use will appear alloy off ( with no one hour to fast ).
The first four reasons caused the bearing off, not alone, but the spindle bearing alloy all almost at the same time off.
In addition to the above five kinds of reasons, the main bearing bolt looseness; crankshaft roundness error exceeds a certain requirements; bearing and shaft neck assembly clearance is too large; bearing and shaft neck with the contact surface of the contact point is too small, uneven distribution, also easy to cause the main bearing alloy break off.
Hazard: the alloy after falling off, so that the main bearing and shaft neck serious looseness, hit each other on the work, the sound came out, if not immediately stop ( at least be idle, low speed to the nearest repair ), still forced to travel, will cause burning of the connecting rod bearing parts, serious when still can cause fracture..



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