Hi, on the Delta V plus if the fan fails the turbo pump will soon stop due to overheating. So, it is probably good idea to replace yours as soon as possible. I have already replaced the fan on two of our instruments. In one case it took 12 years to fail, on the other it took 8.
The replacement is straightforward, just be sure to shut down the power first to avoid any electrical shock. In our case, all operations were done at the fan itself, just pay attention to where the cords go and it should be an easy job.
Of course, you will need a replacement first. A local supplier of fans had a very similar to the one in our instruments, it has been working pretty well. But if you are desperate and can't find a replacement in time, a standing fan close to the pump will do the trick (it won't look fancy, though).
Good luck,