Take a look at those pressure gauges, deformed due to high ambient temperature. The plastic shells literally melted, as well as all soft plastic stuff around the power pack!
This relatively large (1000L) power unit, mounted inside a 30ft container, was used to power special hydraulic tools of a large drilling rig, that punched geothermal wells on Azorean Islands.
The cause of the overheating turned out to be both simple and dumb. The power pack was equipped with oil cooling/filtering system that used a separate group 3 gear pump to circulate the oil. Two main electric motors were powered by 600V/60HZ, and the circulation pump motor by 380V/50HZ three phase current.
The rig would stay on one site for no more than a couple of months before moving to the next drilling location. Every time the container got moved, all the external power connections were disconnected. The 600V extension cable was always the same, but there were a whole lot of 380v extensions all over the drilling site, and a different one was used every time the container moved.
No need to say that there was no effectively established extension phase order, and so each time a new connection was made there was a 50 percent chance the circulating pump would turn in the wrong direction, which it did for extended periods of time. And there you have it - the warm Azorean climate, a closed container, a cooling system rendered useless, and the powerpack working 24/7 - it doesn't get much hotter than that!
Note to self - "when staring a hydraulic unit, don't forget to check if rotation direction of the three phase motor is correct!"