Your call ?
About $58 for teh part and 1hr or two.... If every thing else is OK its worth teh $$$
If you think not, then what do you intend to spend to replace it with a like machine or more up market ? If you like volumetric and steam milk and shot at teh same time, the next step is quite big.
If 4 years and this is you first big problem, then the EM6910 has paid for its self a few times over ;D