Someone please help if you know about air compressors, warning, long. So I have a Campbell Hausfield compressor from around 96 for home use. Its a 60 gallon upright from a tractor supply.

Had problem with my compressor shutting off, so I replaced the valve at the bottom of the copper tube where it meets the top of tank and it worked for a long time.

The tube started to get hot so I replaced it (the valve) again thinking I got a bad one. Still had problems and replaced the pressure switch.

Seemed to be okay for a few months till I worked it a long time and was under my car when I heard something fall, the plastic air cleaner melted off the head, and the tube was cherry red again. Motor made noises so I bought a new one from master tool repair, their updated universal motors do not have a dedicated unloader line like the original so they sell you a brass T connector, so the unloader line comes off off the head at in the same fitting that the main tube to fill the air.
I broke it in with the mobil 1 oil the suggested, it ran fine with no load (valve open at the bottom so no pressure) for over a half hour.

Problem is the first time I used it the unloader line (the one they give you is vinyl or plastic) melted at the head and blew off.

I thought maybe I did something wrong and bought a new line and just installed it, the tank only ran for maybe 10 minutes, I put my hand near the fitting at the head and could feel the heat coming off, and a few seconds later it blew off again. What am I overlooking to constantly get failure after failure?