My 2008 A6 Quattro has 200,000 miles on it, so I'm hesitant to put too much money into parts. That said, the fundamentals (engine, trans, frame) are all still very good. I'm just trying to see how many extra miles I can get from it without heavy costs.

The main thing that bothers me about it is that ride is fairly crashy when I drive over moderate bumps and potholes. Also... there's a fair bit of vibration at idle, which I know the mounts can affect.

I've replaced the struts all around, along with the front upper control arms and a few other bits. When I look at the suspension now, nothing jumps out as a culprit. Even the trans mounts look good.

At one point, a year or so ago, I had a motor mount code, but it went away by itself. The mounts don't look broken to me, but I don't know if they would show anything much. The fact that this is a 200,000 mile car suggests the mounts are probably shot, though.

On this car, at least one of the mounts (maybe both... need to look again) has an electrical connector. But a lot of the cheap aftermarket parts are dumb parts; they have no electronics. I'm interested in the cheaper parts because of the age and lack of value in the car. My questions are:

1. I don't have the classic thunk noise as I shift from park into drive or reverse. Has anyone experienced bad motor mounts that *didn't* exhibit the usual thunk when shifting out of park?
2. Has anyone substituted dumb mounts for the kind with electronics? If so, how did it work out?
3. Does anyone know what sort of signal the electric mounts send to the car, and whether a dash fault light can be avoided? For example: a brake pad sensor is simply a wire that gets broken when the pad is too worn, causing an open circuit and a code. So you can splice the wire and avoid a dash light, if you're so inclined. Is the signal being sent by the motor mounts similarly basic, such that I could avoid fault codes even if I install dumb motor mounts?

Thanks

 

Maybe the engine is just running rough? Maybe some sensor is starting to fail or vac leak or clogged injector, crap plugs... etc.

 

The plugs and coils are quite old. Vacuum system is working enough to not throw codes. Where would you start if you were troubleshooting a rough idle? Maybe replace the plugs if the age is high enough?

 

We had a 2006 A6 wagon, got rid of it at 186k miles. I would see a fault code stored for one of the engine mounts if I went in and scanned the modules. It never caused a CEL, if that's what you are asking.

I would not skimp on such basic things like coil packs and plugs.

 

Right. There was a brief time where I would also get a code for the passenger side mount, but then it went away, and now it doesn't show codes even in VCDS.

As for plugs and coils... I see your point, but this is also a car with a lot of age and miles, and a lot of things that are necessarily not-quite-perfect. The idle vibration is subtle, and I don't notice any actual misfires... if I started to really dive into all the things that are just a little off (for example, the vent system will often click a few times before changing modes, probably because of stripped gears on a blower door... the exhaust is very slightly loud, but not to a point where there's an obvious culprit... the suspension has various control arms that could be replaced, but look essentially ok... you get the idea). If I start replacing everything that would be replaced in an ideal world, the slope gets very slippery.

 

I've been buying used cars for years. I will never buy off a lot, to much of a loss. I usually go in the 5-10 yr old range. Usually second owner, which is nice to have old records.

The way I look at it, car payments would be around $5000-10000 a year, so if I spend less than that in repairs on my car, I'm winning. New cars cost too much, so I say keep fixing it until you don't like the car and grow bored of it.