Old post but thought I would be provide my experience. I just received a used MSI MEG z390 Godlike motherboard (I would have never purchase this new for its insane retail price). I visually inspected the board and found the following.
1) Same oily residue in key points;
a. under thermal pads where m.2 ssd drives were. You could still see the impression the SSD’s made in the thermal pads that run the length of the SSD, on top and bottom of the drive. There was also black what I would almost say was soot (although not powered you could blow off) framing the impressions of the chips. The oily residue was mostly in little droplet forms. It all wiped away with a paper towel and light amount of windex.
b. I removed the very large heatsink and heat pipe system from the MOSFETs. Major oil residue around these thin MOSFET chips that also have thermal pads (black in color as opposed to the grey on the m.2). This is the same little droplets, as well as dark shiny smooth around the chips on the actual motherboard. The top of these chips do have the oil with only the lowest 3 MOSFETs having excessive oil on the chip. Possible the heatsink and thermal pads do not sit tight on these chips and the oil was able to get between the mating surfaces. No oil on the larger silver VRM’s. No thermal pads touch these, even though the heat sink sits partially above them (although not touching them which seems like a poor design). At this point I did not clean this up as I decided to send a message to the seller for him to explain all this. I took more apart but refrained from attempting to clean the oily residue around any chips, here and else where. The thought ran across my mind that maybe this board was submerged in one of those oil tanks for super cooling a PC. I didn’t see signs of oil in every nook and cranny so highly doubtful unless someone hosed it down with cleaning solution and dried thoroughly.
c. Removed the decorative cover (with actual heat sink that seems pointless, since it’s covered) for the south bridge chip haha (I’m old), I mean PCH chip. This is under the large LED dragon logo. The same black thermal pad there with oil residue all around (same droplets and smooth darker shiny motherboard surface). I notice this is not were the chips make contact with the pad but only around the perimeter of the chip. This is definitely not some type of thermal compound. The thermal pads all seem to have a solid layer of plastic (that makes contact with the the chip) and a spongy foam core, designed to not use thermal paste. If it is coming from the foam core it would have to permeate the plastic, which is possible if it’s that type of plastic that can allow liquids under high temps and/or heat to leach through. Maybe that is how thermal pads work, not the leaching out part put the foam core having an oil to transfer heat.
2) other oddities;
a. The metal shields around the RAM slots were discolored and had an almost iridescent sheen. Almost like the heat/chemical treatment on metals to give them that iridescent look. It rubbed off easy to show the shiny chrome like original metal underneath. I was almost thinking this residue was all over, at one point, and the seller cleaned off every where he could, except for under thermal pads and such. And somehow this residue discolored this metal. The same metal shield around the PCIe slots was not discolored but they seem to be a stronger metal that maybe have a different finish/coating?
b. The long narrow OLED on this board has a plastic cover/window to frame the OLED thin board underneath. This little window had some residue in the corners and again looked like the residue was all over the window at one point. Looked like the window was wiped clean except tight into the corners. This residue was not in little tiny droplets, like the other areas, and was not oily. It cleaned up easy with windex, a paper towel and a small plastic tool to get into the corners.
c. Dark/shinier areas on backside of MB around chips that seem to line up with the VRM’s and MOSFETs. There were no droplets and no thermal pads here.
If it wasn’t for the rest I would have thought this last point was residual flux from manufacturing that was hiding under chips, with this being such a thin coating on the MB. When the chips got super hot the flux ran out. Maybe it is and the other areas are this plus oil from the thermal pads as well. It could not be only flux, at these other areas, with the amount there was in full-on droplets and such. Then there is the grey thermal pad for the m.2 drives that have no....well I was going to type “no chips” but yea, there are open chips on all these SSD’s and of course I don’t have the SSD board sitting there to make a better determination. I know this board was meant for severe overclocking and probably seen some extreme heat and torture. It was probably a mistake to purchase such a board used, especially in a system I use to render 3D models and not normally for just gaming.
I just got back to finishing this long post and the seller got back to me, in the meantime. He said he unfortunately does not know the background on this board. Only gets in items, verifies they work and resells. He said I am welcome to return it. I will wait till I have a chance to test it this weekend (after I clean things up) and see how it performs. Major work to swap MB’s. I already have an i9-9900k in a open liquid cooling loop, with an MSI z370 Gaming M5 MB, that cannot handle this CPU (thus the MB upgrade). With this new MB, I also have a new CPU block being delivered Wednesday. This is a nice EK CPU block that actually covers the VRMs as well as the MOSFETS, so the stock heatsink will be left off.
If anyone is interested, I’ll report back with more view points on the oily residue, once I clean it all off and see if the board performs as it should. Then pull it apart and look for more oily residue.