Proper troubleshooting an overheating Dell XPS 15z

Question

So I am fairly sure that this issue lies in the Hardware department seeing as I loaded up Ubuntu on a bootable USB and still got the same result as starting up Windows on a friend's DELL XPS 15Z laptop. The problem persisted just the same.

What I've tried:

• Updated the BIOS to the newest version.
• Tried a separate OS, problems persisted (I would assume that would rule out the software as the issue).
• Reapplied the thermal paste between the heatsink and CPU properly.
• Made sure the fan is working and ducts are clean.

The problems that are ongoing are the computer overheating right above the CPU under the keyboard, and as a result of the overheating, when a program such as Chrome is started on either OS, the mouse starts to lag very badly.

A quick google search shows that this seems to be the norm with this particular laptop. However, the answers for remedy are all across the board. Anybody know how to properly go about the troubleshooting or to help out??

Any help is much obliged in advance!

Answer 1

I have already seen this issue and successfully repaired it. The answer is simple: Your heatsink is defective!

The heatpipe in between the CPU and the heatsink is no longer functioning, so the heat does not transfer. Simple way to know is that no heat is coming out the exhaust port, but the CPU is heating up the motherboard.

I was pretty surprised as well when I saw this. My guess is that the heatpipe heats up too much and vaporizes the internal gas/liquid. Or it is simply a defective batch by Dell. Replacing it returned the customer's temps immediately back to normal.

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For diagnosing this type of issue in a laptop here are the steps:

1) Inspect all air vents for dust, and verify if the fan is correctly spinning. If there is no correct airflow, there may be a dust bunny inside the fan which means you need to dismantle the fan itself. (and the laptop) You can use compressed air to try to clear the heatsink/fan using the vents.

2) Check for internal temps using a software such as HwMonitor or Speedfan. Anything above 70C is usually bad sign, especially if the CPU is idle.

3) Using task manager or a process explorer, single out anything that may be making the CPU run at 100% capacity, thus overheating it. Eliminate this if needed.

4) Verify for BIOS updates on said laptop. If nothing is available, I suggest trying another older OS and see if the overheating stops.

5) Verify the thermal paste on the CPU, as well as if the heatsink is correctly seated.

6) Verify the heatsink itself. If only the CPU heats but no heat is transferred, then the heatpipes may be defective, and the heatsink assembly needs to be replaced.

7) If all this fails: your motherboard or CPU is defective. It is overheating by itself.

• I'd be happy to see other steps here. Please comment if you have some. I do this for a living after all. xD