The left fan was making the noise of a lawning machine...
The repair went quite ok, until I found out that the connector of the fan was different than the one of the replacement fan. Maybe this is due to the age (6 years) of the machine or to the origin (bought it in Switzerland). So I had to cut the wires on both fans and weld the old plug onto the new fan. After that installation was a piece of cake...
Expect the unexpected, this way you won't panic