I've been noticing the rear suspension of my 2000 528iT Sport slowly loosing its compliance. While driving down the street over minor bumps I don't really notice anything, but when I go over frost heaves on the highway at high speed, the front takes the bump just fine, but the rear suspension gives me a harsh ka-thunk. I raised my concern to the dealer during my last regular service. In July Roundel, Mike Miller addressed a similar issue. I copied Mike's response and provided it to the dealer. The dealer said that they didn't notice anything, and if they wanted me to check whatever it was that Mike had recommended (I now can't find my July Roundel!!), it would cost me about $700 if the part wasn't bad (I have a 10 yr extended warranty), so I declined. A few weeks have passed, and I returned to my dealer. This time I drove with the shop foreman, and he confirmed the ka-thunk. He said he'd research and get back to me, and when he did he said it is the shocks and gave me a replacement cost of $900. Ignoring the price for the moment, I have a hard time believing its the shocks. I experience none of the classic symptoms of worn shocks (lack of control, bouncing, etc.), and after all of my research it seems that these shocks should last longer than my 85,000 miles. Of course, I don't want to replace the shocks if this is not the problem. Any thoughts? Might it really be the shocks, or should I ask the dealer to be checking something else? I believe I have the self-leveling suspension.
I am not an expert but shocks do go bad at 85,000, and many times before that, especially if you hit a bad pothole or speedbump. If you do not trust your dealer and his diagnosis, maybe you need another mechanic. You need to find out exactly what kind of suspension your vehicle had. I would guess self leveling suspensions tend to have more expensive shocks and components than a regular non leveling suspension. With the dealer repair, you do have recourse if the problem isn't solved.
At the amount of miles you have I doubt seriously that you have a shock issue. I have had two of these and my current is at 105k, previous at 97k and have several clients with well over 100k and all still have original rear shocks and shock mounts in place. With that said all needed rear subframe mounts in the 80ish mileage range and on my current the two rear subframe mounts were split wide open when I replaced them at 95k. These mounts carry the whole rear end and will create all of the issues you describe. Cost on these escapes me at the moment but with the correct special tools it shouldn't bill more than about 2 to 2.5 hours. If I were you I would get a second opinion outside of the dealership where they actually work on real world, high mileage, non-warranty vehicles. Try www.bimrs.org for a reputable independent and 2nd opinion.
