How do you tell if a heatsink is Stuffed?

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Woolly

119 posts

Master Geek
Inactive user

# 17770 10-Dec-2007 20:59

Hi Guys

I've got a Dell Dimension 8400 and the heatsink pipes are at skin temp when the computers going.

The CPU fan is not loud but may have been a lot quieter when I first bought it.

Can anyone else with a heatsink put there fingers on their heat sink pipes and say what temps they're getting?

I say touch because Dell disabled or obscured any temperature measuring (I presume to stop overclocking).

Any help appreciated.

Cheers Woolly

Fraktul

836 posts

Ultimate Geek

Trusted

# 99348 10-Dec-2007 21:31

If your fan is not working well you would expect the heatisnk to be hotter as it is transfering less energy to the surrounding air mass.

The only instance where there may be a problem if there were insufficent thermal transfer between the device doing the heating and the heatsink which could cause the heatsink to feel cooler.

Woolly

119 posts

Master Geek
Inactive user

# 99355 10-Dec-2007 21:55

I thought of that so I went out and bought some Nano Thermal Grease. Took off the heatsink and cpu cleaned up with alcohol. Applied new grease thin layer and then put back together again.

Still skin temp on the copper tubes at the base.

After some research I see other Dell 8400's have the same problem and fix it by replacing the heatsink.

What I can't understand is why the copper tubes quite close to the CPU aren't even maybe a little bit warm.

Is there some kind of fluid in the Heatsink (refrigerant?)

Cheers Woolly

Fraktul

836 posts

Ultimate Geek

Trusted

# 99359 10-Dec-2007 22:21

Woolly: I thought of that so I went out and bought some Nano Thermal Grease. Took off the heatsink and cpu cleaned up with alcohol. Applied new grease thin layer and then put back together again.

Still skin temp on the copper tubes at the base.

After some research I see other Dell 8400's have the same problem and fix it by replacing the heatsink.

What I can't understand is why the copper tubes quite close to the CPU aren't even maybe a little bit warm.

Is there some kind of fluid in the Heatsink (refrigerant?)

Cheers Woolly

Yes, it is filled with a fluid which heats, evaporates and condenses within the different thermal gradients of the pipe.

Woolly

119 posts

Master Geek
Inactive user

# 99360 10-Dec-2007 22:31

Ok so say the heatsink is in contact with the CPU Ok but the fluid has leaked out.

Would the copper pipes not get warm?

Does the fluid evaporate if it leaks?

What is the fluid?

Cheers

Fraktul

836 posts

Ultimate Geek

Trusted

# 99371 11-Dec-2007 01:00

Woolly: Ok so say the heatsink is in contact with the CPU Ok but the fluid has leaked out.

Would the copper pipes not get warm?

Does the fluid evaporate if it leaks?

What is the fluid?

Cheers

Yes they would get warm.

Yes.

Probably alcohol or similar liquid with a low evaporation point.