How Dell proving that they are using Element 13 thermal paste on X series for their customer?

Based on what I known, Element 13 is liquid and sealed inside the compartment, so whole machine is Thermal paste and Element 13's combination. 

Hi @doremo welcome to this user to user discussion forum. This is not Dell Support. 

Dell Support do not usually interact with this user to user forum.

Please use your Dell account ask for creation of a Service Request so that Dell Technical Support can respond to your concerns. Advocate that your Service Request should Reject the service engineer's use of common thermal paste.  

Alienware X-Series laptops use Quad-Fan cooling and a pad instead of a paste. The pad is made of encapsulated gallium-silicone, and its designation is Element 31, because gallium is element number 31 on the Periodic Table. An image of this new thermal interface material (TIM) pad is not included in many reviews. There is the inevitable speculation that gallium liquid metal will eventually ruin CPU and GPU, and motherboard components. 

Surprised that your Alienware x17 R1 motherboard has been replaced, you did not say why. 

Alienware X-Series Quad-Fan cooling system

Alienware x17 R1 Service Manual, Removing the system board, says processor (CPU) is to have Mylar barrier sheet installed for return of motherboard. (Do not use an alcohol wipe to clean the Element 31 thermal grease from the processor (CPU) chip. The alcohol solution from the wipes will dissolve the Element 31 grease into conductive metal particles. If these conductive metal particles come into contact with the surface of the system board, it will cause the an electrical short when your computer is powered on.) 

Alienware X-Series processor (CPU) Mylar barrier sheet

It is clear that the Alienware x17 R1 Service Manual says Element 31 is designed by Dell to be used in the manufacture, and during motherboard replacement. Element 31 has significantly improved thermal conductivity when compared to general thermal paste. 

The service engineer is usually a contractor and not a Dell trained warranty technician, but covered by Dell warranty. Dell supply of replacement motherboard will have included the Element 31 pad. Advocate that your Service Request should Reject the service engineer's use of common thermal paste before the CPU is damaged by excessive thermal temperatures. 

Please click on Kudos to say thank you for response from user that is not employed by Dell. Please share an update on progress, so that other users derive benefit from your experience. Thank you. 

The Element 31 encapsulated gallium-silicone pad looks like a grease with edge barrier, after installation, the pad is compressed by screwing down the heat-sink assembly, the bonds of the silicone are broken so that gallium liquid metal is applied to CPU chip and heat-sink assembly. (Click on image to expand and then outward facing arrows, to see more detail.) 

Alienware Element 31 pad on a CPU chip

Alienware's x15, x17 gaming laptops wield radical 'Element 31' cooling | PCWorld  

I already denied the replacement as the engineer look like don't know X series is using different material

When i asking about Element 31, the engineer just showing me a big tube of the common thermal paste, telling me that they all just using this when replacing the main board

and showing me that the thermal paste look like has been removed on the replacement heatsink

now i am worried if the machine is built at the site office and not from the factory,  is the engineer using Element 31 when building the new machine?

Hi @doremo  the Element 31 pad provides a 25 percent improvement over the thermal grease Alienware was using. When pad crushed, Element 31 has the appearance of thermal grease. 

Dell has provided clear instructions on how to return system board: "Once the system board assembly has been removed from the computer, follow the instructions in the tech sheet dispatched with the replacement system board assembly." 

The Alienware X-Series Service Manual says the "17 CPU Barrier" tape shall be used. Label text says "17 CPU Barrier - IMPORTANT! attach the tape to the CPU before returning the System Board - 17 CPU Barrier". Same instructions apply if replacement System Board is also subsequently returned. 

Did service engineer read the Dell tech sheet and text on the "17 CPU Barrier" tape label? 

Did Dell Support create Service Request to undertake their Service Manual process? 

Hi @doremo thank you for sharing update. Its down to you to decide if your Alienware x17 R1 replacement system board build should have the Dell common thermal grease or the Element 31. 

Please share an update on progress, so that other users derive benefit from your experience. Thank you. 

This is the case last month when the engineer come to my place, I ask the engineer is the replacement mainboard come with a specific Element 13 thermal pad

The engineer take out the mainboard and heatsink showing me that the thermal pad seem has been removed from the heatsink, and he take out a tube of thermal paste from his bag telling me that they all just using that common thermal paste for all laptops

So i denied the replacement and i explain to the engineer i don't want to bear the risk if he don't use the specific Element 13 thermal pad, I don't want raise the ticket again because of overheat if after the replacement

The reason why my x17 R1 need to replace the mainboard is that i reported twice with the speaker crackling sound issue when i just receive my laptop

Hi @doremo  thank you for sharing update. 

The service engineer is not Dell. Only Dell Support via the Service Request can get this problem resolved for you. Get your Service Request update escalated to senior Dell tier that has authority to authorise your remedy. The longer you wait, the more difficult the resolution. The system was delivered with fault(s), ask for full return of all your money as your preferred remedy. 

Please share an update on progress, so that other users derive benefit from your experience. Thank you. 

of course  the engineer is from Dell, the case logged in Dell website

Hi @doremo  thank you for sharing update. 

The service engineer is usually a local private contractor that was paid to replace your motherboard. 

Please share an update on progress, so that other users derive benefit from your experience. Thank you.