Best to call service and ask before you go there, even if it's just for an oil change which is usually fairly quick. There are a number of factors that affect the length of time between when you drop off your vehicle and when it's ready again such as: how many other jobs are ahead of you, whether all their techs are working (or some-one's out sick that day), and what you need done.
I totally agree with Shiela's reply to Terra. Depends on what time of the month too. I think they're busier at the beginning of the month because of people's payday, and taking care of vehicle maintenance.
For routine service (oil change, tire rotation) the wait is generally 1 to 1.5 hours. An appointment is recommended for diagnostics as depending on the problem, diagnosis and repair can take a few hours to several days.
I made an apt for my car and when I brought it in, they said they would not even look at it for 6 days. Dedinitely call them before you waste your time. You might want to try gresham subaru also.
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