Chasing a front end clunk
 

Since I purchased this 2011 XJ Base N/A CPO car, there has been a slight clunk over small bumps in the road at low speed. Also, while driving slow, you rock the steering wheel left and right, you can hear the clunk. The clunk is slowly getting louder.


I took it in and had the following replaced.
*Front shocks
*Upper Shock mounts
*Sway bar Bushings
*Sway bar links
*front control links
*upper wishbones complete with bushings and ball joints
*1 engine mount (CPO warranty would only replace one) warranty expired 14 days ago.
*transmission mount
The only things left are the other engine mount, which I am going to do and the lower Ball joints. (but they are tight).


Now I am wondering if it is actually anything to do with the suspension, or is it something structural or steering or? Any suggestions where to look would be great.


Note, every time I take it in and they do an alignment. The clunk seems to go away for a little while, but it slowly returns. It seems after the car was lifted up in the air, it solves the clunk issue for a little while until it settles back down, then it returns. I was hoping they would find it under warranty, but that time is passed.

If you look in the picture below, look at #7, the front lower forward control arm ( also known as the banana arm ). The big round bush, those are common to fail, sometimes they leak because they are hydro filled for NVH. #6, which is the rear straight arm in the picture, the big round bush to the inside has been known to fail, but not nearly as common as the front one. You should be able to get the bushes by itself, but will have to be pressed out. If you see them leaking, they need to be replaced. Since you mentioned every time you get the alignment done, the noise goes away, but comes back. The eccentric bolt for the caster adjustment runs through the front of arm #7, #6 the camber bolt runs through this one. I'd get #7 and #6 checked to see if there is any movement or the bushes are leaking.




1Subframe
2Spring and damper assembly
3Upper control arm
4Wheel knuckle
5Wheel hub and bearing assembly
6Lower lateral control arm
7Lower forward control arm
8Stabilizer bar
9Stabilizer bar link




https://topix.jaguar.jlrext.com/topi...E126642/en_US/

Thanks JBzXJ40 for the diagram.


problem is I have replaced item numbers with new Jaguar parts.
2,3,6,7,8 (bushings), 9.


The only thing I have not replaced is item number 4. Two places including the dealer said the lower ball joints are fine. So either I bite the bullet and replace those and hope for the best, or look for something else? The car has factory brake pads installed by the dealer.

I didn't see any mention of the control arms or bushes so that's why I was mentioning that. As for the vertical link/knuckle, yes those have been known to fail, that set up goes all the way back to S-Type, but Im not sure on the XJ if the lower ball joints are available separate. Its very likely that lifting the car, and doing the alignment is changing the geometry of the suspension enough to eliminate the noise, but as it settles, noise returns.


One way to check your engine mounts is to open the hood/bonnet, put it in Drive, apply park brake, place one foot on the brake, and press the accelerator to see if one side of the engine lifts up, if it does, then you have a bad mount.

Oh wait a minute, nevermind. I see front control links, I thought you meant the end links for the sway bar, those have been known to fail as well. #5 in the picture below.




https://topix.jaguar.jlrext.com/topi...E126643/en_US/




ItemDescription1Subframe
2Spring and damper assembly
3Upper control arm
4Wheel knuckle
5Stabilizer bar link
6Wheel hub and bearing assembly
7Lower lateral control arm
8Lower forward control arm
9Stabilizer bar

JBzX40. Yes #5 stabilizer links were the the first things I replaced. I'm hoping I find the source of the knock and be able to post a solution. I might try removing the sway bar temporarily and see if that helps.

Replaced other mount. Slight knock in front end still there.

With the car turned off (i.e. no power steering) is the knock there if you rock the steering wheel? If so, you probably have a joint gone in the column. Happened to me on the 2012 I recently bought at under 40k miles.

Polyesterpig (or anyone on here! - Did you ever get this resolved? I have a 2011 XJL SC with the same issue. Took it to the dealer who stated that the bushings for the lower forward control arms were bad. Changed them myself with Jag genuine parts but still the same issue. Sounds like a rock the size of a software in a wooden box that rattles when hitting any road imperfection. ******* wanted to charge almost 2K for the replacement. Cost me less around $450 for parts. Good thing considering the issue isn't resolved.

Here is what they repaired on my XJ that resolved all my front end noise

Honestly, this makes since because the stabilizer bar is hidden under the cover/shield. A quick look/inspection for the issue and noticing a worn bushing for the front lower control arm without looking at the stabilizer bar would certainly deduce the issue there. Hopefully after taking off the cover, I'll spot it. If so, I'll go back to Jag and "let them know!". ;)

Update : The XJ has 95K miles on it now. I had the plugs changed at an independent shop last month. I told him about the knock and informed him of EVERYTHING I had replaced at the dealership. He called me and said my front sway bar bushings were worn and were causing the clunk. I informed him I already had those replaced. He held to his diagnostic. Since his cost to change the plugs was half of the dealerships price, I gave him the go ahead on the sway bar bushings. I asked him if he would guarantee that this would solve the clunk/knock. He wouldn't, but he REALLY believed this was the issue. Well after 1000+ miles on the new bushings, the knock is finally gone! I didn't want to post right away, just in case the knock came back in a couple weeks. Drove the car from California to Las Vegas and back, and a few weeks going to work and back. NO KLUNK. Like a new car! The sway bar bushings were the first thing I replaced many miles ago? I chased that clunk with many dollars and time. Makes me wonder if they were actually changed at the dealership the first time? Well at least at 95K miles, all of my suspension is near new. Good for another 95K miles.

From my past experience chasing front-end clunks on my old X350, the sway bar bushings will always be the first thing I try.

I see you're in SoCal, so I wouldn't be surprised if the dealer cheated you.

If in doubt, when checking in the car tell the SA you want the old parts if it's you that is paying and if its warranty ask to look at the old parts. I know there are some disreputable service facility that will show you an old part that didn't come off your car but you have at the very least notified them that you do want proof of repair. IMHO

Has anyone tried these yet?

https://powerflexusa.com/xj-x3512010.aspx

Poly bushings last forever but can give off a slight squeak. If the bushings on my car start to fail I will be switching them out to poly!

Well, I read that with interest, especially when mentioned that the clunk appeared to go away after being lifted.
I had an S-Type back’ in 2000 that had an annoying clunk which was difficult for the Jaguar dealership to trace. I’ll cut the the Chase. The anti roll bar bushes when under load became oval and provided clearance to two sides. When the car was lifted with the wheels hanging the bushes went back to their designed circular shape. I went to three dealership with this problem, neither of them knew what they were doing unless they did know what the fault was but wouldn’t accept that it was a design design.
The point was that on each occasion that the car went in for inspection to trace the fault whilst under warrantee, the fault was fixed by lifting the car, when lowered and driven away it was perfect, but by the following day the clunk returned.
After a trip to an independent jaguar specialist where he fitted non OEM bushes and also increased the torque settings to suspension points the clunk was no more.

Yes the S Type is well known for front sway bar bushing noises.
The XJ not so much?
Also don't forget to change the sway bar end links too. They are cheap and can be a source of noise.
Thanks for reporting back what the fix was!
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Every time there was a clunk in my X350 XJ, it was the sway bar bushings, and the X351 seems to share a similar, if not the exact same, setup. And each time it was the same deal...I would waste time and money replacing something else and the clunk would disappear for a few days but then return with a vengeance.

The second time it happened, I didn't suspect the sway bar bushings because I had replaced them the first time just 3 or so years before and I didn't think they could wear out that quickly. But I was wrong. So from now on, sway bar bushings will always be first on the list.

On the S Type the replacement bushings seem to hold up much better than the factory ones. I also put silicon grease between the bushing and the bar to help with squeaks.
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