My wife has been complaining about a persistent metallic-sounding rattle that has developed in her XK8. It seems to originate in the right rear of the trunk. I assumed it was coming from my tire tools shifting and rattling around so I cleared the trunk of everything in it (including the spare tire) but when I test-drove the car, the annoying rattle was still present. I agree that it sounds as if it is originating in the right rear of the trunk. The ragtop hydraulic pump is tightly bolted down, and so is the battery bracket....

Any other ideas as to what could be causing this?

 

Does it occur at low speeds over uneven surfaces? Lumpy roads, bricks, etc?

It could be the lower shock bushing in the rear or the shock itself with an internal rattle. There have been several reports of changing a shock being the only fix.

 

Speed doesn't seem to matter, but the noise is easier to hear at low speeds. I'm not sure that smooth vs. rough roads matter, either....

I read the thread about the noisy ragtop frame earlier this morning. So I dropped the top and hit every joint I could find in the ragtop frame with a shot of white lithium grease....

Then we took the car out for a joyride with the top DOWN and the tonneau cover securely in place. We did not hear the rattle at all in about 40 miles of cruising. So I hope this fixed it. We'll see how it does the next time my wife takes her car out with the top up....

 

I'm still thinking shock bushing ... but I HOPE I'm wrong.

 

I hope you're wrong, too! But thanks for your input....

 

You might check your exhaust pipes and the tips to make sure they are secure and don't need to be re soldiered.

The soldier joints can break loose after awhile. Start with tip and move your way back.

Good Luck.

and remember

Happy Motoring...

 

Jon89,
I had a rattle for the past month that increased with speed til it became a hum, but when slowing or lifting off the throttle, disappeared or slowed to a rattle or a tapping so it seems. Over the last few days it became louder, and whereas I originally thought it was coming out of the engine or supercharger, upon more intense listening and having someone else in the car listening, we found it was actually coming out of the back of the car. I limped it into my mechanic, yesterday, and today he reported the differential is shot with a bad bearing (I always figured it was a bearing, just didn't know where). The good news is that it wasn't the engine or supercharger, the bad new is....

 

A slightly loose handbrake cable can cause the rear brake shoe mechanism to 'rattle'.

A 13mm deep socket will tighten the locknut on the threaded rod under the propshaft at the diff area. A few turns while 'tapping' on the slack cable will determine if is the rattle you are hearing.

DO NOT OVER TIGHTEN.

bob gauff

 

Update:

I took the car out for a quick spin this morning with the top up. Unfortunately, the rattle in the rear persists. A knowledgeable friend says that it sounds like a shock issue to him. Never having had to deal with a shock problem before, I honestly don't know. But given the frequently-reported suspension noise issues on these cars, I'll start there....

So what's the best way to inspect the rear lower shock bushings to determine if they are the culprit? And are these bushings part of the shock itself, or are they pressed into the lower wishbone where the shock is bolted to that assembly?

Any expert guidance would be much appreciated. Guess I've been very fortunate in that I've never had to deal with a shock issue before....

 

The bushings are pressed into the shock.

You can lay on the ground and get your fingers on the bottom of the shock. If you have a friend gently bounce the rear of the car you should be able to feel the knocking if it's the bushing that's the problem.

On my car, I bounce the rear and can hear the tap-tap-tap but can't feel it in the bottom of the shock, which makes me thing it's something internal with the shock.

 

Thanks, Charlie. Next time my neighborhood buddy comes over when my wife's XK8 happens to be home, I'll give your bounce-and-feel suggestion a try....

So what is your next step towards diagnosing your particular issue?

 

Honestly, I have given up trying to diagnose it in the car. It's had the rattle since I got the car (2.5yrs) and it hasn't gotten any worse.

I found a pumpkin out of a wrecked 2004 and am having it rebuild with all new bearings, hardened / phosphate coated ring and pinion and a Quaife LSD. You have to drop the rear cradle to install the diff anyway, so when that comes back, then the rear suspension will get a complete going over.

New R package shocks, Adamesh springs, poly panhard bushings, poly subframe mounts, all new control arm bushings, differential mount bushings, a larger rear sway bar and Tony's special super sway bar links.

I plan to get the old CATS shocks back to see if there are any rebuild options. Avos was able to do this in Europe so surely there is someone in the states who can.

Bilstein says they can rebuild shocks, but I've heard mixed stories about whether they will do the CATS ones from out cars. When I called, they needed the actual part number stamped on the shock housing, so I'll check again once I have them out of the car.

 

Wow. Sounds like a significant rear-end refurbishment. How much will all of this work cost you?

 

Labor to install it, not sure yet, but dropping the cradle isn't that bad a job if you have a lift and the right tools. I won't tackle this one myself because 1) the cradle mounts need to be pressed in and 2) the car will need an alignment after it's all done and the independent I go to can take care of that at the same time.

The full set of bushings, spring packers, spring isolators and other plastic/rubber consumable parts isn't as much as you might think. About $400 in all.

My car has sagging front springs and is sitting too low, but after searching high and low I wasn't able to locate OEM front springs for a reasonable price. Adamesh springs were $390 for all 4 corners.

The UltraRacing rear sway bar is $238, so again, not terrible.

The end links (4 corners) were $500. They are way over engineered and made of titanium. Pricey yes, but c'mon they're titanium, how could I pass that up? Just think of the weight savings.

Now the bad part: CATS shocks are $400 each, so that's $1600 right there. I debated rebuilding the set I have but not having any idea how long it would take, or even if I could find someone to do it, I decided not to risk taking the car out of service without having a defined path to get it working again. So I bought a new set of R package shocks, and will investigate the rebuild later. If there is a way to get it done at reasonable cost, it will help the rest of the forum members to keep their cars going, so that's something at least.

The LSD and diff rebuild is a whole new level of silly. The Quaife and bearing kit was $1600. The rebuild is probably going to cost $2500 more, after the metalography to check the ring and pinion, the heat treatment, the shot peen, the phosphate coating and then the assembly and checkout.

So, a rebuild of the wear parts wouldn't be that bad, or you could go totally overboard like I did.

I installed the Avos twin screw kit about two years ago so my love for (and investment in) this car long ago passed what you could call reasonable. Plus I'm an engineer, so just like to tinker with things, and this car is as much a hobby as it is a functional thing.

 

Not directly addressing the problem at hand but, in general, creaks/groans/knocks/clicks, etc. seem to eventually develop in every car and these noises are frustrating and annoying. The weirdest noise I dealt with on a car was my 1995 Corvette. Other than the "normal" noisiness of the ride one thing that would happen was a quite loud creak from the front that sounded like an old creaky bed. But this ONLY happened on real hot days when things got hotter under the hood due to the a/c running. The temp gauge normally was in the 180-degree range and there were no noises but as soon as it started hitting about 200 or above, the creaking would come. Once the engine cooled back down a bit the creak went away. I always thought it had something to do with the suspension components expanding and I never solved the problem.

Back to the Jaguar the good news is that a really annoying rattle from the driver's door window has been successfully addressed by the shop I brought the car to a few days ago, along with solving the gap between the passenger side window and the quarter window. The car is a pleasure now inside without the annoying rattle. Sadly the clunk when I go over speed bumps remains as there is nothing obvious that the shop was able to find. He suspects the right front shock itself but it does not seem to affect the ride or height of the car so I will continue to live with this.


Doug

 

Thanks to all who have provided potential trouble spots for me to check. When the weather cools off a bit I'll get the car's rear end in the air, crawl underneath, and carefully check the aforementioned trouble spots to see what I can find. But with highs forecasted to be in the mid-90s every day for the next week or so, it's not gonna happen anytime soon. I've told my wife to just crank up her audio system in the meantime....

 

Update:

Our weather has finally cooled off a bit so I put the rear end of the car up on jackstands this morning and crawled underneath with my list of components to check. The exhaust pipes and tips were securely in place and the welds looked to be intact. The bolts that I could reach in the shock assemblies were still tight. I saw no fluid leaks from either rear shock. The handbrake cable still seemed tight and did not cause a rattle at the rear brake pads when I tapped on it....

So I started feeling around in the nooks and crannies underneath the rear of the car, pushing and tapping on various components to see if they would move and potentially cause a rattle. When I got to the aluminum-looking heat shields above the two center mufflers just in front of the rear wheels, I noticed that the heat shield on the passenger side was just a millimeter or so away from the chassis frame. When I lightly tapped on that portion of the heat shield, it indeed contacted the frame and made a sound that could be interpreted as a rattle....

So I reached up between the heat shield and the frame and carefully bent the heat shield away from the frame, creating about a finger's width of distance there. I then went to the other side of the car and did the same thing to the drivers-side heat shield even though it was not as close to the frame as the passenger-side heat shield was....

Hoping I had solved the issue I remounted the rear wheels, lowered the car back down on the driveway, and took off on a test drive. To my ears the rattle is still present but now quieter and less frequent. So perhaps I'm on the right track....

We'll see what my wife has to say about it. I'm still not counting out a shock-related rattle since a number of experienced folks here have reported shock bushing issues....

Any additional suggestions regarding how to isolate and identify this rattle once and for all would be much appreciated. It can indeed be quite annoying....

 

Jon, did you pry on the rear lower shocks, were the bushing is enclosed with a large screwdriver or such. Being as they are hanging fully extended, unless you push up on them from the bottom all will feel very firm.


Wayne

 

Wayne,

No, I didn't do any prying on the bottom of the shocks with a screwdriver or other leverage tool. I just pushed on them with my hands and checked the tightness of the bolts that I could reach.

If I use a tool to pry on the bottom of the shocks, what should I feel or hear when:

1. the car is sitting on the ground with its rear wheels in place ?

and

2. the car is up on jackstands with its rear wheels removed ?

Thanks for trying to help....

 

Jon, when the pry bar is under the shock with wheels on the ground you will not be able to get a true feel as the weight will be on the bottom part of the bushing with the rubber compressed, so hanging will give you a pretty good chance of feeling for movement. A real good idea is to take the bolts loose holding the shocks, just a turn or two so the side pressure is less. If you get more than a 1/4 inch the bushing needs attention or something is a miss. I checked a front one and it moved so much with the bolt loosened I was worried the sleeve would be frozen on the bolt.


Wayne