The main aim is to control thermal expansion in aluminium piston at high working condition. A plasma sprayed ceramic coating (TBC) is applied on the piston crown as a top coat and NiCrAl is applied as the middle layer as bond coat to improve the addition strength between the top coat and the metal subtract layer as AlSi alloy; we introduce a thermal slot on the piston shrink to regulate the heat flow in piston and make it cooler. We analyse the piston with these two implementations to determine the thermal analysis of the piston. The results can be shown in the various comparisons of coating thickness of top coat with thermal slots on the piston shrink. Increase in coating thickness reduces the stress in the coatings. It is observed that 85°C increase in 0.8mm coat than the ordinary piston.