Cooling laptop without GPU with CPU/GPU combo heatsink

[iicaie]

Hi everyone, first time posting here. I have a laptop that doesn't have a GPU and the CPU is currently passively cooled with a single heatpipe going to a heatspreader? kind of thing. It doesn't even have fins on it, not to mention a fan. I've applied fresh thermal paste but the temps still stay in the high 70s under load like they used to. As this same series of laptop (Lenovo G40) has a version with a GPU on it, I found a heatsink/fan combo for that particular model. 

 

My question is, will it do more harm than good by swapping out the existing cooler for this? I'm unsure what the behavior of the new heatpipe will be, because it runs first from the GPU -> CPU then heatsink/fan. I'm concerned if heat will end up at the GPU cooler side of things and end up sending more heat into the motherboard. The new heatsink only costs about 15USD so I'll go ahead and make this a weekend project if you guys think it will work without any adverse effects. I welcome all constructive opinions thanks! 

[DakotaWebber]

5 minutes ago, iicaie said:

high 70s under load

Why would you want to do this? This is acceptable temps

 

Where would you plug in the new fan if your current one doesnt have one?

[WereCatf]

2 minutes ago, DakotaWebber said:

Where would you plug in the new fan if your current one doesnt have one?

It looks like the header for the fan is on the board, right where the heatpipe changes colour from copper to black.

[iicaie]

7 minutes ago, DakotaWebber said:

Why would you want to do this? This is acceptable temps

 

Where would you plug in the new fan if your current one doesnt have one?

Mostly so the keyboard doesn't get so hot and also for fun. But I wouldn't want to waste time disassembling the whole thing just to find out if the new heatsink starts channeling heat the wrong way or anything like that. Thanks!

[iicaie]

6 minutes ago, WereCatf said:

It looks like the header for the fan is on the board, right where the heatpipe changes colour from copper to black.

That's correct! 

[19_blackie_73]

if you somehow manage to isolate the gpu heatplate from the motherboard electrically, I don't see why it won't work. HAving a Die there or not won't change how the heatsink works. Though high 70s isn't to shavy for a laptop, and I doubt your keyboard will be much cooler afterwards.

 

[iicaie]

6 minutes ago, 19_blackie_73 said:

if you somehow manage to isolate the gpu heatplate from the motherboard electrically, I don't see why it won't work. HAving a Die there or not won't change how the heatsink works. Though high 70s isn't to shavy for a laptop, and I doubt your keyboard will be much cooler afterwards.

 

I have some spare kapton tape for electrical isolation, I guess I'll just go ahead with this then! As for the keyboard getting cooler, I was hoping I can type on it after I perform the heatsink swap, currently it's uncomfortable resting my left hand on it even for 1 minute.