Dell 4030 Cooling Issue

Hi , 

I have dell n4030 laptop since about 3 years.

This year im facing heating problem although i opened and cleaned the fan and other all components but it gets hot and turns off. It works in winters somehow but in summers any heavy work done make it turn off.

I think i have to change the heatsink with fan. Fan is working.

Please provide the heatsink amazon link where i can buy the heatsink. My tag no. is 

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