A4000D's run notoriously hot. There have been many solutions.
One machine I used to see at the St. Louis show had two muffin fans mounted to each side of the case!
Some years ago the fan in my machine at work froze and took the processor board out with it. I replaced the fan, but the new WarpEngine still got hot.
I discovered that there is just barely enough length in the wires to the motherboard power connector to place the power supply outside the case. I built a frame in place of the PS and mounted a 110volt (mains powered) fan in the opening in the back of the case. I ran that fan to the monitor plug in the PS so that it starts as soon as I power up.
I call this my stove pipe A4000 because the PS sitcks up like a chimney. Ugly as @#$%*!, but it has worked fine for many years.
If I could squeeze the $$$$ for a tower conversion out of my employer, I'd do it in a heartbeat.
Good Luck!
