About a month ago, my 2012 A6 with 49K miles started to idle roughly. A local repair shop diagnosed the issue and found bank 2 intake and exhaust cams out of time and showed me with the head covers removed using an Audi gauge that the cams were out of line. they said that a repair would require dropping the engine and would be expensive. I decided to take the car in to the local Audi dealer. The dealer says that motor mounts are bad and need to be replaced for $1700+.
Need advice on what to do. Concern that if I have the dealer fix mounts, would still need the valve train repair.
If the camshafts are out of time with the crankshaft, that’s a pretty good reason to explain poor idle quality. It sort of seems unlikely that could happen though, unless something unusual has happened, an accident, major engine work recently, accidentally shifted into first at 80 mph, etc. If that stuff is really out of time, more likely to be a problem with the variable valve timing actuators.
What does the first (non-dealer) shop say about the mounts theory? If they agree the mounts are a problem too, one idea, have the first shop replace those, see if it solves the problem. You might get lucky, and they have to be replaced anyway.
It sounds to me like the non-dealer repair shop put the work in to do a good diagnosis and actually showed you the problem. That’s the shop in which I’d put my trust.
Exactly how expensive did he say it would be?
Did the dealer show you the bad motor mount? I’d guess the answer will be “no”. I’ll also guess that the dealer didn’t do any more analysis than a very quick look-see, or even just a guess based on the symptoms?
Cam timing is monitored by the Powertrain Control Module, if the cam timing is off the values on the scan tool will indicate this and there will likely be a fault code and check engine light illuminated.
Depending on the severity of your idle quality concern the problem could just be a failing engine mount(s). This mount may have the same appearance as a new mount so there may be nothing a customer would recognize as “bad”. The mount may be hard and transferring vibrations to the body, this isn’t something you can see by looking at the mount.
Your dealer has experience on their side, they repair these cars everyday.