Strange rattle from rear on 2003 Boxster S
 

Hey there everyone..I hope someone can give me some idea as to what is going on with my car.... I have a 03 S with 89000 on the clock. When I drive the car at speeds over 15 or 20 mph, I hear a rattle (like rocks in a tin can) coming from the rear passenger side. Its easy to hear with the top down and is driving me nuts trying to isolate it. I have checked all the heat shields around and over the cats and muffler, the clamps, mounts and bolts on the exhaust as well. Hit on the cats and muffler with a rubber mallet and cant hear anything rattling. The rattle does not seem to be from exhaust but does sound like a heat shield might be loose somewhere. I have looked at the aluminum heat shielding around the back of the car, but can not find anything loose. Took the engine cover off and found the piece of aluminum on there really loose. I installed high heat insulation in-between the heat shield and plastic engine cover shell which helped some but still hearing that rattle. What could it be? I re-worked the brakes over the whole car using OEM parts. Pads, rotors, spring clips etc...I don't think the brakes are rattling.... Shouldn't be anyhow. Is there something I am over looking? I have raised the car up and checked the suspension more than once trying to find a bad arm or bushing, but can't see anything wrong there either. Even checked the little tail pipe to make sure it was not hitting on something. The sound does not seem to be related to exhaust note but more to motion of the car itself. I would welcome any ideas as to what I might check next.

I had issues with my heat shield. It would sound like rocks in a tin can, but only under certain throttle conditions (lifting was particularly noticeable).

Ended up re-attaching the heat shield, and cutting some away.

Car is quiet now. Take a fresh look at that heat shield.


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The baffles inside the muffler can loosen and rattle. The cure for me was new muffler(s).

You may have a loose spark plug. It happened to me recently. Does it sound like crickets?
The dealer wanted $600 to replace all the plugs. I took it to a local shop and got all the plugs replaced for $140.

At 89K it could easily be the rear trailing arms (#8 in the factory's rear suspension diagram). The forward rubber incased bushings fall apart. Mine were shot at 45K, and would rattle and pop, but only detetectable at low speed, especially going over speed bumps or similar. I got urethane rebuillds from Vertex, easy job.

If it rattles just on acceleration and deceleration check your oxygen sensors are tight. I had a similar rattle and both sensors were loose on the LH exhaust

Exhaust heat shield

Have checked the heat shields and suspension components and still can't isolate that rattle. I am about to give up. Is is possible that it could be convertible top components??

You sure you don't have on of these in the trunk?

You are in Texas after all . . . :D

http://986forum.com/forums/uploads01...1369619748.jpg

Take a rawhide or rubber mallet and give all 4 catalytic converters a whack...not too hard mind you, just enough just to see if the the honey comb internals have come loose...

Thanks for the heads-up Porsche Chick..I am certain there is not a rattlesnake in the trunk, but it sure would make it easier to fix the problem if there was...LOL! Since I recently replaced the brakes and rotors, is it possible that that noise is coming from my hand brake being out of adjustment? It takes about seven or eight clicks to engage firmly. Is that too much play? It really sounds like loose brake components the more I listen to it. I have whacked the cats and mufflers, poked and bent all the heat shields that I can find that are remotely loose and pounded the suspension components with a rubber mallet over and over to no avail. Kinda sounds like loose calipers on an old pickup from the eighties or nineties if that helps any. I think I am going to look into the hand brake....Anyone else ever had hand brake issues??

Hand brake is easy to adjust. Remove the cover off the bottom of the centre console storage, just need a couple of spanners.

I had a similar noise in my 2001 S. When I went to change the transmission oil recently, I removed the aluminum plate that protects the transmission a rock(!), about the size of a golf ball, fell out. Problem solved!

is your E - brake working correctly ? the springs inside could make that type of noise

Ok, checked and adjusted the hand brake. Still have the noise. I did have a bunch of gravel and small rocks on the plastic shielding that is under the car...removed the rocks as well. While checking park brake operation and play (passenger side), I noticed that the inner CV boot was torn. Pretty good tear and while there is still grease inside the boot I am wondering if the CV joint is past it and needs replacing. Was thinking of just replacing the boots or should I go ahead and buy new axle units as a whole assembly I am really good at changing boots and re-packing CV joints, but 89000 miles has to have taken somewhat of a toll. When I move the axle back and forth, I can hear a slight clicking noise. I don't hear that on the other side (driver side) of the car when I jiggle the axle back and forth. I don't think the CV joint is bad, and would rather just replace the boots, but is this normally what is done or does one just throw away the axle assembly and start over?

i would just replace the boots and see what happens .

Southtx...
If your trailing or suspension arms are worn, you will not be able to detect the wear unless you remove the arms - even then its not too obvious. My fronts were knocking badly but pulling / pushing / twisting did not show up the wear - only replacing them fixed the problem.....
Check by driving over a rough surface (I'm sure you have some in TX) with the engine turned off if possible. Be aware you won't have boosted brakes with the engine switched off, so pick a desertd road to try this - you don't have to drive fast to see if the suspension is the problem..

I am starting to agree with a few of you here and think this noise is coming from some worn out suspension component. I am thinking of just going ahead and rebuilding the the suspension on the front and back. Looks like parts might run around 3k, but I can do the labor myself, so only thing I will need after the overhaul is a four wheel alignment/wheel balance. Far as I can tell, the struts are original so I am guessing that I probably need to replace them too. When I have the car elevated, I can literally grab either of the rear wheels and push them up a few inches before I encounter enough resistance to stop me doing so. I can't help but think that probably is not correct and it should have more resistance. Was going to go ahead and replace the wheel bearings while I am in there and re-work the CV boots on the outside, while replacing the whole CV assembly on the inside. Pelican parts has a overhaul kit for about 2100 bucks and seems to have everything I would requite sans wheel bearings and struts. Am I doing the right thing by thinking this way? The car drives great, but it is 10 years old and has almost 90k on it. There has to be some wear and tear on the components. I would love to hear what you guys think....

'Rocks in a tin can' doesn't sound like suspension components, unless it is sporadic rattles over bumps. While the suspension repair would be nice and would no doubt improve handling and ride, it is a lot of money if it does not correct the problem. Do you have a indy you trust? If not, it may even be worthwhile to go to the dealer for a diagnosis before you opt for that much money in parts. If the noise is constant at low speeds, even on smooth payment, I would think that it has to be something else.

If the CV joint boot on the passenger side (where the noise emanates from ) is torn and there is a clicking noise from that side when you move the axle, it strikes me that this is a good starting point (although I would expect you would also hear clunks/rattles when taking off from a standing start if the CV joint was gone.....). I would try to get a diagnosis from a mechanic experienced with these cars before jumping in with both feet.

Brad

I live out in the sticks, so I will need to take it to a shop in either Austin or san Antonio. There are a few good indie shops around and I think it might be time to finally get an opinion on what is going on from someone who knows what they are looking for.