How to make the engine cylinder head without cracks        

How to prevent the cracks of cylinder head, there are the following methods:

1. boil water tank can not be sudden cold

Boil water tank water cooled engine, cooling water evaporation, located in the upper part of the engine cylinder head more easily due to lack of water and temperature rise sharply, sometimes even the appearance of the paint or powder are burned, if the sudden cold, head will crack due to sudden heat quenching.

2. do not let the engine dry start and then add water

Some of the water-cooled engine after long-term use, starting performance is poor. In the cold winter, because of difficult starting, the driver often takes the wrong method of dry start and then add water, which is very harmful.

The 3. winter heavy load operation not immediately after discharge

For the use of water as coolant of the engine, the winter after water must be put in the net, but the engine load after the operation, the engine temperature is too high, if the head will immediately turn on the water, casting temperature decreased rapidly, due to uneven stress crack.

4. timely removal of scale in cooling water channel

The engine has been used for a long time, the inner wall of head waterways will generate a thick layer of scale. Scale composition is insoluble calcium carbonate, it will greatly reduce the cooling efficiency of cooling system, and make the parts due to uneven heat dissipation cracks. Therefore, the scale should be removed regularly.

5. do not let the engine work long time under high temperature

Due to long time overload operation, the engine cooling system, poor heat ignition or oil too late, the oil supply is too large or the cooling system of the engine running water leakage, and the turbocharger speed down and other reasons, will make the engine a long time in the hot state, the head is easy to produce cracks.

6. correct installation of cylinder head

The cylinder head has been used for a long time, will gradually warpage. For example, for the joint plane of cylinder head of 4125 diesel engine, if its flatness tolerance is more than 0.20mm, it must be repaired so that its flatness tolerance is restored to 005mm. Otherwise, not only will the cylinder gasket be damaged by the gas leakage, but also the gas leakage will make the cylinder head local overheating, and easy to produce cracks. In addition, the cylinder head bolts should be tightened evenly by 3 times according to the specified order and torque, and then tightened once again after the engine is heated, so as to ensure the sealing of the cylinder head.

All of these are wrong operation, everyone in normal use, we should learn to use manuals and listen to the master of maintenance, so as to minimize the damage and failure of accessories.