That crack is from a recent inspection I did in Fletcher Hills in El Cajon, all one-story hillside homes on landfill. You were there recently, too, huh?
When that type of crack is in the garage and only in the garage, I don’t have any problem with it in a structural capacity, especially in an older home. What has happened has happened. However, I have no way during the course of a multi-hour inspection of determining whether the causes of the crack are active or inactive. So it does need to be monitored. Personally, I would also patch and seal it. I told my Clients the same and that if they were uncomfortable or unknowledgeable about such cracks, they could get more information from a geologist, soils specialist, structural engineer, etc. Although there were no indications of excessive settling activity anywhere else in the home, they chose to get a structural engineer out to look at the crack. He gave them a 17-page report of disclaimers with basically a one-line paragraph at the end: “Crack is common to garages in Fletcher Hills and doesn’t present any structural concerns at this time. Monitor for change.” In other words, “Welcome to Fletcher Hills!”
You say the garage was attached to the home. I’ve never seen that in any state where I’ve done real estate work, whether in cold northern areas, hurricane-prone areas, earthquake areas, etc. I suspect that it wasn’t. How did you make that determination?