If the engine is making "tak tak" noise during driving, it could be due to piston knocking. Main reasons of piston knocking as below:
1. Each con-rod deform due to some reasons, causing piston off-grinding which make the clearance become bigger then lead to knocking. Piston knocking will cause the engine consume more fuel, engine oil leakage, consume more engine oil. When the piston knocking is sever, it might crushed the piston, damage the cylinder causing the con-rod to break.
2. The cylinder and piston show wear sign after the engine running for a while, the clearance between the piston and cylinder become greater due to friction and poor lubrication, causing a step occur at the area slightly below the first piston ring which lead to knocking noise.
3. Piston skirt and cylinder worn out after running for a period cause knocking due to severe out-of-roundness level.
Suggest to perform diagnose at work shop, usually the keypoints of diagnose from the mechanic are:
1. Perform diagnose by adding booster engine oil to the engine to confirm if the piston is knocking.
2. Check the cylinder inside the engine, if the out-of -roundness level is severe or the clearance between the piston and cylinder become too large, replace the cylinder liner, piston and piston ring.
3. Check the bend and deformation condition of the con-rod, if the deformation is out of shape, repair by cold press or replace.