I've completed the mission to get Randy Gett as the mechanic at Ranger HQ however the quest that says "recruit somebody to be the mechanic at Ranger HQ" as a "side quest" does not close or finalise and I find I can't upgrade my vehicle to have radiation protection. Is something going wrong here? This guy is at Ranger HQ but the quest is still marked as being uncompleted and I'm stuck here.

Looks like I'm experiencing bugs with Wasteland 3. Anyone know about a patch I can use to get over these bugs? Thanks!

For the mechanic HQ upgrade you need to resolve the refugee situation with the quest given by the councilman sending you to the Bizarre. Randy Gett is just one guy, not an entire mechanics team, with equipment.