In response to requests, I've added a Common Auto Repairs Database (CARDb) to the site.
Currently it's just possible to add common repairs to the database. When the database has been populated, owners will be asked to report whether or not their car has actually had these problems. So we can find out how common "common repairs" actually are.
My suspicion: usually less common than people think.
The form includes a field for a forum thread URL, so people can be directed here for thorough discussions if there is a thread discussing the repair.
Common Auto Repairs Database (CARDb)