I was dong this 15 year ago when the heat exchanger for the 3081 failed. Open the windows at one end of the machine room, and the loading bay doors at the other end, and let the breeze through.
Put the PFY by the doors to keep out curious users and bob's yer uncle
The need for secure data centres really killed off ambiant air cooling, now we have to use forced air cos open windows* aren't secure.
* Insert your own Microsoft joke here.