Also note: when replacing, you need to clean off and replace the thermal compound on the chip dies. And technically the screws should be tightened down in the order shown by the numbers next to each screw...that is to try to ensure the thermal paste is spread evenly/correctly across the chip die when tightening.

Responding to this oooold comment: Part# 5H40W36671 5H40W36671 - Lenovo Laptop CPU Fan & Heatsink - Genuine

You can look up, and sometimes order, Lenovo parts at their website. They even sometimes have instructions and videos for parts. Many models also have service guides available, at least the Thinkpads do (maybe because they are intended as "corporate" machines).
https://support.lenovo.com/us/en/parts-l...