Macbook Air mid 2013: Heatsink screw on the fan side broken off

[tinykl]

Hi! I renewed the thermal paste and didn't realize the heatsink was mounted with a single fifth screw on the fan side that is very difficult to even reach. I removed the four screws on the CPU side, left the fan attached and carefully bent up the heatsink to remove the thermal paste. In the process it got off completely. I didn't understand how to reattach it after I was done with the thermal paste, since I thought it was just attached to the fan with this rubber thing somehow. Only after looking at an ifixit tutorial, I realized there was a fifth screw. :-D

Now, on the fan side, the heatsink is standing up a few millimeters (just 1 or 2). You can push it down, but it will come back up again, obviously because it broke off at the fifth screw. My question: Can I just leave it like that? I'm thinking the casing will actually press it down in place after being reassembled. How important is this screw to fix it in the exact position? I would replace it, but it's a complicated procedure and the spare part is very difficult to get where I live. And I'm thinking it's probably not necessary. Should I just run a benchmark to see how well the cooling is working now?

Thank you!

 

[maerz001]

1mm distance is alot for a heat sink.
I don’t think the housing is designed to press against the underlying processor. At an impact this would ask for breaking.

You can rund it as the processor should have internal thermal switch off or at least throttle.

But i guess with 1 mm it will perform worse than with old heat paste…

 

[tinykl]

Well, obviously it would only work under the assumption that the housing is holding the heatsink in position, cause then the 1mm would be 0mm again, lol. I only mentioned the 1mm to describe how the heatsink behaves when the housing is off.

The housing doesn't need to be designed to press against the processor, but against that rubber thing on the other side that glues the heatsink to the fan. And it doesn't need to be *designed* to do that either, it just needs to do it. :-D An okay solution to make up for the missing screw would probably even be to add more "filling material" on top of it in case the housing doesn't do that. It's possible that missing screw doesn't really do anything at all, and is just for convenience to make it easier to close the housing properly, if you know what I mean.

Anyways, I checked the temperatures, and so far it's doing totally fine, under moderate/somewhat heavy usage, it averages 75°C with peaks at 90°C. Temps on idle are below 60. That's probably all not that interesting though, since the fan doesn't seem to much or anything at all. Tomorrow I'm gonna run a benchmark to see if the fan cooling is working properly.

 

[maerz001]

Well as long as it runs you are fine for now.

I know for high power LEDs that i assembled a 1mm heat paste layer would kill them long therm. This stuff is compared to a heat pipe still like a very bad heat transmitter. So minimal distance is crucial