I’ve noticed a thunk in my ‘12 XK convertible when I go over bumps. Seems more pronounced when it’s cold and after it’s driven for awhile, doesn’t seem as noticeable. Thoughts?

 

I replaced the top mounts and spring dampers, and everything is tight and quiet.

My 2013 vert. only has 40,000 miles, but the mechanic said it's the age of the parts that causes deterioration.

I bought parts on eBay and had my local indie shop do the work. Total cost was about $1,000.00

Ron

 

Thanks. My car just rolled over 29K, but the age issue might be the problem. I was hoping I could just tighten something and avoid a parts bunny hunt, but I’ll take it to the shop.

 

The front suspension usually makes a knocking sound from ball joints. Thunks could com from a worn damper above the shock, possibly a worn subframe bushing, or lastly an engine mount, in that order. For a start, the last two are easier to check, I think.

 

I had a thunk in the front over bumps, and was a bad shock/damper. Replaced with a used part, all quiet now.

 

I thunk, therefore I was. . . . .

 

Well, I had thunks, clunks, and every other noise I could think of on my front end, and since it had been over 115,000 miles since I had replaced my shocks the first time, I thought I'd order new ones. at 225,000 miles, I wanted my car to feel like it had when I first got it. Took the car into my mechanic where we replaced all front bushings, sway bar links, etc. went to order shocks and they were impossible to find in stock, It took me almost 4 months to get them. Had them installed but still had a knock so we replaced control arms as well, and now everything is great. Feels and sounds just like it did when I first got her.

 

Was the thunk noisier at first and then lessen after driving a bit?
wj

 

It was more related to the surface I was driving over. Cracked or uneven pavement caused all sorts of noises.

 

Yeah, seems like it gets less as I drive it longer. It’s very obvious when first driving. Maybe the longer I drive it the more I want it to go away…? Seems to be more pronounced on the right side.

 

Probably the shocks are getting worn. As they are used the friction tightens them up, quieting things.
@ 120k miles mine were quite noisy, I replaced with used xkr assembly's, with 65k miles on them. Every thing was improved but still noticable. My friend just took delivery of a 53k mile xkr, it has a very slight 'rattle' for a mile or so and then it is gone.
WJ

 

Thanks! I thought about that, but figured since the car only has 29K on it that wouldn’t be an issue, since my understanding is that the OEM shocks were Bilsteins. I thought about bushings, but that would be constant. I’ll start the XK shocks bunny hunt so I’m ready when my mech breaks the bad news.

 

I replaced my mounts and it was lessened, not totally removed. Almost liiveable.
wj

 

To close out this “thunk” thread: replaced the front struts, strut mounts and upper control arms AND rear inner/outer tie rods, sway bar links and upper control arms. No more “thunks.” Ride is pretty firm, still doesn’t like abrupt, sharp bumps in the pavement (nobody uses low profile tires for their cushy rides, I suppose) and it goes around corners like a slot car. Bilstein B4s for the front were $1100. Glad I listened to my Frau and picked up the insurance. It softened the blow…

 

BTW, had MAF sensors cleaned and new air filters installed while the front wheels were off. Took it out this morning to fill it up and at the gas station got a “nice ride,” so the pain of fixing the XK is fading.

 

Did you do the work yourself or have a shop do it? If the latter, would you mind sharing the labor cost?

My 2008 has been thunking for a little while and has now added a squeak to the sound effects, so I think a front suspension rebuild is in the near-ish future.

 

I used an independent (AG Motorsports) here in Memphis. I don’t have the space or inclination that I had 10 yrs ago.

Figured (hoped) initially that it was “just” a shock replacement, but it was obviously more in depth. It started out small, but got to the point where it exceeded my tolerance level.

Arman runs AG and I have confidence in something he tells me, unlike the Helen Keller-esque mechs that “inspected” it at the M-B dealership here where I bought it.

 

Were the upper mounts shot? The foam material they are made of tends to just fall apart with time, and sounds horrible over sharp bumps once it's gone, due to the metal on metal contact.

 

That was part of it, on the right front. Left looked normal. There was a bit of that brown plastic stuff on the top of the right mount, but as my mech got further into it, he found more stuff.

 

Hey A6, just figured I'd say hi...We met a few months at Eurofest here in Memphis, I was parked next to you with the black XKR and the little kids running around. Glad you were able to get your front end noise sorted. I finally got around to doing my own front end bushings & boots a couple weeks ago. Happy New Year! I am sure I'll catch you at another event soon enough.