billcar9999

I'm chasing a noise problem on my 08 Z06 with about 26K miles. I have Pfadt sport shocks and Pfatty sway bars. My problem is a rattling noise on the left side of the car that does not transmit to the steering or brakes. The noise certainly seems to be initiated by the front wheel but is louder when the rear wheel hits the same spot on the road. I get the noise on really smooth roads but isn't any worse on rough roads. Above 50, the noises go away.

Here's what I've found so far, not necessarily in order:

The shocks were initially the focus of the noise because the right rear was loose once. I assumed the others were loose too. I've taken the shocks off and used loctite on the nuts. The installer did not use loctite when they were originally installed. I thought that it could also be sway bar related and spent a lot of time working the front and rear end links. I had an experienced Vette shop work on them too with no luck. Finally, I reinstalled the OEM bars but the noise is still there with no change.

The coolant overflow tank was a little loose and I tightened that up.

A clip holding a hose to the steering rack was broken (used a tie down strap for a temp fix). This helped reduce the amount of noise up front.

The top of washer fluid tank hits the hood release cable. I'm not sure this is significant enough to cause the noise I'm hearing. I checked the front bolt on the tank and it was tight. I can't access the rear bolt, assuming there is one.

The left rear brake duct was really loose compared to the right and bag is missing. I had big hopes for this being the problem thinking that the noise just transmitted through the body. I've stabilized it until I can get it fixed at the dealer. This helped reduce the number of rattles but it's still there. I suppose this could still be the problem.

Checked everything else I can think of including the exhaust.

My current working theory is that the transverse spring is loose (lowering bolts backed all the way out). I'm thinking that the noise I'm hearing is the spring being completely unloaded during low speed driving. I don't know how driving faster would change this other than down force. Is this a valid assumption?

Other observations:

The car scrapes a lot more often than before.

The right front bump stop on the shock looks like its bottoming out. The others look OK to me. The shocks have a collar that the bump stop hits on downward travel. A couple of them move around a bit. I don't know that I cause enough noise to be the problem. I thought about using something to immobilize them but haven't yet. If this were the problem, I assume they would still make noise at higher speeds.

I've only checked this on the left front so far. The transverse spring can be lifted easily a little with a short pry bar. I'm not sure this means anything or not because the car was on a jack with the wheel off. The lowering bolt has 1 inch exposed above the spring. I tried to turn the bolt (clockwise) but it was really tight. I didn't want to force it and wasn't sure I was turning it the right direction. Visually, all of the lowering bolt bushings look OK and I don't see any indication they are sliding around or worn.

I'm starting to hear a new squeaking sound from the rear on hard bumps that reminds me of a worn out coil spring. It reminds me of a 64 chevy wagon with bad rear shocks but not nearly as bad. I'm not saying the car rides like that but I can't think of any other way to describe the sound.

I have never changed the ride height but the car looks lower more now than before. I attribute that partially the the NT05 tires I put on recently. I had the noises before I put the new tires on. Compared to another Z06, my car is about a 1/2 inch lower in the front (fascia to ground). Measured (finger method) from the bottom of the fender to the shoulder of the tire, the height is consistent.

The noises are driving me nuts. I'm taking the car to the dealer next week to get the brake duct and clip problem fixed. I don't really want them tearing into car without a plan. I'd rather guide them to things to check.

What am I missing? Are my assumptions about the spring correct or am I wasting my time?

WFO

I also have the the PFADT coilovers and had clanking over the smallest of road imperfections. CALLED Pfadt spoke with Aaron. He made a recommendation. It appeared it was in the mounting nuts. So we double nutted and loctited...overkill yes, but it fixed the problem. Love the suspension and no more noise..none.

My suggestion, if you haven't already, is to call Pfadt. They might be able to give you some things to try.

billcar9999

I've already talked to Jordan and Aaron mainly about the sway bars but they recommended the loctite for the top shock nuts. The loose shock issues I had seem to be solved. The sound I hear is different than the shocks made and comes from lower in the car.

MatthewR

I sugget you check the ride height bolts that connect the springs to the lower A arms. If your car has slowing been lowering itself, the rubber ends on the aforementioned bolts may have be slowing trearing themselves apart and you'll get noise from the metal bolt poking through and contacting the aluminum seating surface of the lower A arms.

billcar9999

I saw the thread about this problem on your car. Happen to have any pictures? I'd like to compare them to mine.

MatthewR

but follow the ends of your fiberglass leaf spring. At the ends are large bolts that have (essentially) a flat washer covered in soft rubber. Looks like an Oreo cookie. The rubber can get pushed/torn off the ends so the metal washer end pokes through. If so, it comes in contact w/ the aluminum lower A arm perch --this will makes noise and the car is lower in the process.

esikofua

I need help. My 1999 vette rattles over rough roads. I just installed new sway bars with metal endlinks, shocks and x-pipe with headers. I just put the car on jack stands and it looks like the adjusting bolt on the leaf spring has too much play. Help