Take PILKR8G8 (thread diameter: 12mm; torque range: 15-20N) for example, according to the data tested by our test bench, after installation, the thickness of the gasket is between 1.23mm and 1.4mm. If the thickness is less than 1.23mm, it means that you use too much force, which will easily loose the iron shell and the ceramic body, or break the iron shell. If it’s over 1.4mm, air will leak through the gasket and the ceramic body can be easily broken.
Therefore, proper torque should be applied, or it may cause serious consequences of engine damage.