Rear Suspension Failure?

[MattB]

I took my car to a local Infiniti dealer today because I'm getting a metallic rattle every time the car goes over a bump and a resonant whine at 2000RPM. I figure it has to be a loose heat shield or something. The dealer tells me that in addition to needing a new muffler (this would be the 2nd one in 30K on this car (!)), the rear beam bushings, struts, and boots are bad. Another dealer I talked to for regarding a price comparison for parts and labor was incredulous and said he'd rarely seen the rear suspension on anything like a 90K mile 2001 I30 fail. I haven't noticed anything strange in the way the car drives other than the noise. I'm taking it to this other dealer next weekend for a visual inspection and second opinion (at no charge, this makes me like this second dealer more already), but is it common for rear suspensions to wear out at this kind of mileage? The car is not driven very hard by any means.

[MTZI30]

One of my rear struts went bad, probably because of the boots.

[MattB]

One of my rear struts went bad, probably because of the boots.

What were the symptoms of its failure? I can't identify anything wrong with my car other than this rattle which sounds like something is loose.

[MTZI30]

Pretty bad body roll from the rear. Didnt even notice it until i got new struts on. The rattle does sound like a muffler problem. You'd prolly save money if you found a good exhaust shop to do any needed repair or replacement.

[the converted]

Make sure that you jack spare tire and anything else back there are properly secured. I haven't heard much about the suspension linkage wearing out, but I would guess that it is about time for new struts with that mileage. I'd also be pretty weary of a dealer trying to give you a new muffler at 30k miles.

[MattB]

I'll check everything in the trunk. I'm pretty sure the noise is coming from the underside of the car but I could be wrong. Also, my front suspension was checked and confirmed as working properly. It also bothers me that the dealer that did the 90K service (in November last year) inspected the rear suspension and said it was fine, and two months later another dealer tells me it needs a full replacement.

As an aside, if my rear suspension is bad, could it be replaced with an I30t suspension? My understanding is that rear struts and springs are the only difference between t and standard models (no front suspension differences), and if it's not any more expensive for the parts (and from what I've seen it isn't) I'd prefer the stiffer I30t suspension.

I also checked my records and the muffler was replaced almost exactly two years and 12K miles ago. Shouldn't an OEM muffler last longer than that? The other thing that bothers me is that the labor to replace the muffler last time was $250. I'm now being told that it's almost $500 in labor for the muffler and mid pipe. Something doesn't add up. The dealer I'm taking it to next weekend for a second opinion did the muffler replacement, so if it has failed again I may try to get them to convince Infiniti to cover it as goodwill (not that I would expect them to, but it's worth a shot).

[MTZI30]

How many miles have you gone? If it bothers you mention that to the service adviser. Tell em look you guys JUST had this car wtf? You can absoluty go with another rear suspension. I put some tokico blue struts on and they were cheaper then stock. You'll wanna do the strut mounts and boots at the same time. Now the muffler, in what way is it damaged? Did you hit something? Is it rusted through? Ask the dealer what they are getting their times for replaceemnt from? Are they just pulling those times outta their you know whats or do they use alldata? Ask for specifics....

[mr0x]

Sears or any tire store will do a free suspension check. For suspension parts, if it's broken, it's pretty obvious from visual inspection.

For mufflers, I don't think a damaged muffler would make a rattling sound before making your car sound loud.

Resonant whine sounds like wheel bearings. Struts will not make resonant whining. Simple check, jack up the rear and turn the wheel. If it's uneven movement around, then it's wheel bearings.

Metallic rattle over a bump might be a muffler but it would have to be in pretty bad shape and in 30K miles it's not very likely. Jack up and peer under the car. The muffler would be rusted and hanging loose for that to happen. It could be that the muffler came off it's rubber grommet and is loose.

[MattB]

How many miles have you gone? If it bothers you mention that to the service adviser. Tell em look you guys JUST had this car wtf? You can absoluty go with another rear suspension. I put some tokico blue struts on and they were cheaper then stock. You'll wanna do the strut mounts and boots at the same time. Now the muffler, in what way is it damaged? Did you hit something? Is it rusted through? Ask the dealer what they are getting their times for replaceemnt from? Are they just pulling those times outta their you know whats or do they use alldata? Ask for specifics....

The 90K was done at 89,658 according to the receipt. As of yesterday's dealer visit, the car showed 90,824. I've done less than 1200 miles since the 90K. The dealer that did the 90K is the one I usually take it to, but they couldn't take the car yesterday so I took it to another dealer, who recommended the suspension and muffler work. So either the dealer that did the 90K completely missed a huge problem, or the dealer that looked at the car yesterday is trying to sell me on unnecessary work.

The service advisor told me that some clamps (?) and other hardware were corroded and to fix this required replacing the midpipe and muffler. I've crawled under the car, and while some of the hangers look a bit rusty, the only damage I can see to the muffler is a slight dent in the lip of one of the tailpipes. The car also doesn't sound like the exhaust is broken. It sounds and rattles like something is loose. When I get a second opinion from another dealer next weekend I will ask them to show me the problem and ask where their repair prices come from.

[mr0x]

How many miles have you gone? If it bothers you mention that to the service adviser. Tell em look you guys JUST had this car wtf? You can absoluty go with another rear suspension. I put some tokico blue struts on and they were cheaper then stock. You'll wanna do the strut mounts and boots at the same time. Now the muffler, in what way is it damaged? Did you hit something? Is it rusted through? Ask the dealer what they are getting their times for replaceemnt from? Are they just pulling those times outta their you know whats or do they use alldata? Ask for specifics....

The 90K was done at 89,658 according to the receipt. As of yesterday's dealer visit, the car showed 90,824. I've done less than 1200 miles since the 90K. The dealer that did the 90K is the one I usually take it to, but they couldn't take the car yesterday so I took it to another dealer, who recommended the suspension and muffler work. So either the dealer that did the 90K completely missed a huge problem, or the dealer that looked at the car yesterday is trying to sell me on unnecessary work.

The service advisor told me that some clamps (?) and other hardware were corroded and to fix this required replacing the midpipe and muffler. I've crawled under the car, and while some of the hangers look a bit rusty, the only damage I can see to the muffler is a slight dent in the lip of one of the tailpipes. The car also doesn't sound like the exhaust is broken. It sounds and rattles like something is loose. When I get a second opinion from another dealer next weekend I will ask them to show me the problem and ask where their repair prices come from.

The cheap multi-piece clamped mufflers suck. They always fail at the clamp. A welded muffler is a little better.

The clamp would have to be sliding around in the pipes to make a rattle. Then remove the clamp or cut it off and replace with another clamp.

I doubt you'd need to replace the mid-pipe though. The mid-pipes are expensive!

[MattB]

It's an OEM muffler. It shouldn't be cheap...

[the converted]

I know the bracket for the exhaust hanger on my maxima's mid pipe rusted off. I just welded it back together and it held up for a few years.

[mr0x]

It's an OEM muffler. It shouldn't be cheap...

Maybe snap some pics and post them.