Heat sink question

[rdsii64]

My exhaust fan stopped spinning, so I hopped on line and ordered another one. After looking at a service manual and one or two you tube vids, swapping them out looks pretty easy. Here is the catch. To do this you have to remove the processor heat sinks. This is easy enough with the right tools. What I don't know is whether or not you have to replace the thermal paste when you put the heat sinks back.
Please advise

 

[Tesselator]

My exhaust fan stopped spinning, so I hopped on line and ordered another one. After looking at a service manual and one or two you tube vids, swapping them out looks pretty easy. Here is the catch. To do this you have to remove the processor heat sinks. This is easy enough with the right tools. What I don't know is whether or not you have to replace the thermal paste when you put the heat sinks back.
Please advise

If in fact you have to remove the heat-sinks from the CPUs then yes you should clean the surfaces with acetone and reapply new thermal paste. Are you sure you have to tho? That doesn't sound right to me. <shrug>

 

[rdsii64]

If in fact you have to remove the heat-sinks from the CPUs then yes you should clean the surfaces with acetone and reapply new thermal paste. Are you sure you have to tho? That doesn't sound right to me. <shrug>

According to the vids I think I do, I really hope I'm wrong though. Hopefully someone who has done it will chime in
If it makes a difference my Mac Pro is an early 2008 8 core

 

[Tesselator]

According to the vids I think I do, I really hope I'm wrong though. Hopefully someone who has done it will chime in
If it makes a difference my Mac Pro is an early 2008 8 core

As far as I know its just a single screw and the twin-fan assembly slides right out on the 2008.

 

[rdsii64]

As far as I know its just a single screw and the twin-fan assembly slides right out on the 2008.

The twin fan assembly is in the front
I need to remove the single exhaust fan at the rear.

 

[Tesselator]

The twin fan assembly is in the front
I need to remove the single exhaust fan at the rear.

Check your PMs for a link to the service manual and see Page #62 for instructions.
You don't need to remove the heatsinks.

 

[666sheep]

You have an excellent opportunity to clean internals off of the dust. I'd suggest disassembling whole unit completely, give it a good dusting, including the PSU. Removing CPU and northbridge heatsinks and replacing thermal paste on them would be good idea as well. If you feel that you can do it ofc.

 

[DanielCoffey]

You could always find a competent buddy and offer a couple of bottles of nice Craft Beer as a thank you for doing the work...

 

[rdsii64]

You could always find a competent buddy and offer a couple of bottles of nice Craft Beer as a thank you for doing the work...

That would be a nice jester but I thought it was easy enough. After I found what is really involved, it will be easier than I anticipated. So when I'm done I will invite a buddy over and offer him a craft beer why I show off my machine.

 

[nanofrog]

What I don't know is whether or not you have to replace the thermal paste when you put the heat sinks back.
Please advise

Yes, if you want it to be done properly (old paste may not flow as it should <heat + age>, leaving gaps/voids that can cause overheating).

Removing the existing paste, making sure the CPU and heatsink surfaces are clean (acetone can be used in a pinch, but 99.x% Isopropyl alcohol is safer as it's far less likely to cause any damage <acetone is far more aggressive solvent & eats plastic, removes PCB legends, and if allowed to sit on a PCB long enough, starts to solve the epoxy in the PCB itself>), then reapply new paste is the right way to go.

Not expensive, doesn't take much time, and is easy to do, so there's really no reason not to do the job properly IMHO.