replacing a thermal pad with paste?

Hi again.

I was going to replace the thermal paste in my IBM R40e 2684 but i was reading the hardware maintenance manual and it says it has a thermal pad. so i don't know whether i could replace the thermal pad with paste. any advice?

You can. A thermal pad is usually a solid piece of gunk that melts when the CPU gets hot and bonds the heatsink to the CPU. It'll take a bit of work to get the CPU off, usually.

Stick it in the freezer to get it cold and brittle.

Then you just clean up the surfaces like normal and apply whatever paste you have.

right ok then. so the thermal paste would be enough to fill the gap between the heatsink and CPU? so you would stick the CPU in the freezer right?

The freezer will make the gunk brittle enough to pry it off the heatsink.

Said By apemax

right ok then. so the thermal paste would be enough to fill the gap between the heatsink and CPU? so you would stick the CPU in the freezer right?

Thermal pads can be quite thick compared the to the paper thin layer of thermal paste (where the rule of thumb is the less the better). If you're doing this on a CPU heatsink, you're probably ok since the springs and screws can clamp down quite a bit and fill up the space. But when replacing thermal interface material (TIM) on memory chips or MOSFET chips, you should get a new heatsink that is designed to work with thermal paste or try to find a replacement thermal pad.

Here is a guide with some good pictures of what to expect when inside a laptop (which is what I think you're working with here).
http://www.insidemylaptop.com/apply-thermal-grease-laptop-processor/
It suggests using a screwdriver to scrape the thermal pad off but DO NOT do that. You will destroy the surface of the heatsink. Even hard plastic can dent and deform soft copper (which is what most heatsink bases are made of).

I would also suggest using a hair dryer or heat gun to heat up the material to scrape it off, then use a cotton swab with 99% isopropyl alcohol to thoroughly clean the surface. The pads are designed to get softer when hot so they fill in the gaps of the two materials. It will be easier to clean off when it's goopy rather than cemented on after it cools and hardens.

Overall, I would not bother with tearing a laptop apart to replace the TIM because the heatsinks are so complicated and cover so many chips at once. If you pull one off, you pull them all off, meaning you should technically replace all TIM on every heatsink base. Are you having some sort of overheating issue that is killing your productivity? Maybe try one of those laptop coolers that have a couple fans in them instead of tearing your machine apart.
http://www.hardwarelogic.com/articles.php?id=5389

yes this is a CPU heatsink and yes it is a laptop. it's not really overheating as such but i have noticed the fan come on more. i've tried SpeedFan to see what temps it is running at but the only temp that it detects are the hard drive and acpi temp.(not sure what that actually is)

Try CoreTemp for measuring CPU temperature:
http://www.alcpu.com/CoreTemp/
Try running a 3D game or something processor intensive to give it a workload. If it stays less than 50 degrees C, then you've got nothing to worry about. If the idle temperature (with nothing happening on the computer) is already over 50C, then it might be something to worry about.

I tried CoreTemp but when i tried to start it it came up: this processor model is not supported.