B737 MAX 8 Captain reported; while conducting a pre-flight walk around; the left wing leading edge was coated in ice. Maintenance technicians arrived at the aircraft and informed the Captain they were performing a procedure to release a frozen left wing anti-ice valve.

Narrative

During my preflight walkaround in ZZZ; I noticed large amounts of airframe rime icing on the leading edge of the left wing. The right wing was clear on anti-iced surfaces. When I discussed this with the inbound Crew; they told me they were making a logbook entry for a failed left wing anti-ice valve. The First Officer also informed me that they had received either a ROLL/YAW ASYMMETRY or a ROLL AUTHORITY annunciation during the approach; with the autopilot engaged; due to the asymmetric ice build up. Local ZZZ Company Maintenance Control showed up and began working the issue. They informed me that this was a known issue with the left wing anti-ice valve on the MAX aircraft and their procedure was to cycle the Wing Anti-ice switch three times with the isolation valve closed using the APU bleed air valve. This procedure was supposed to un-freeze the stuck valve. They went on to say that due to the design angle of the left wing valve that it has a tendency to freeze up. The procedure was successful and we departed for ZZZ1 53 minutes late. During climbout I used the wing anti-ice and had no issues.I have concerns with dispatching MAX aircraft into known icing conditions with a faulty designed valve and no flight crew guidance on how to unfreeze it in icing conditions. Maintenance Control has a procedure yet we don't. Our QRH procedures simply instruct us to avoid icing conditions yet fail to instruct us to cycle the valve up to three times as Maintenance Control does. Boeing should issue an AD requiring a fix to this issue or a procedure should be given to flight crews to deal with this faulty valve.