In the blast pit level, the action of turning on the giant fan that is used to propel the character to the roof of the building causes the game to crash. The game crashes roughly about 10 seconds after the fan is turned on. Attached is the mdmp of the crash. Hope you can get this issue fixed, the rest of the game looks awesome 
hl2_4104_crash_2012_9_15T22_6_43C0.mdmp (82.9 KB)
Yes, same problem here, after like 10 secs the game crashes.
This happened to me but not at the fan, just somewhere else…
Really need to open another ten topic instead reading old topics with solution?
https://forums.blackmesasource.com/showthread.php?t=12620
(There is a box or fragment on the vent. Yes, you don’t see it, but if nothing dropped onto the ven, then it’s work fine. Just reload the autosave.)