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C6 Corvette ZR1 & Z06General info about GM’s Corvette Supercar, LS9 Corvette Technical Info, Performance Upgrades, Suspension Setup for Street or Track
Greetings - I have replaced the end links - front and back, greased the stock sway bushings with dielectric GM silicone grease, re-torqued the axle nuts (RR was hand tight) and tightened two muffler hanger bolts which were backed out a little. The car is much tighter feeling now and all usual suspects addressed. I think. No clicking or popping making turns etc. When I go over subtle bumps or small pot holes, it sounds like the hatch is loose or exhaust hitting something. I wiggle the exhaust and feels very sound. I did not Popeye forearm it though. I checked the battery tie down and it is solid as a rock.
40,035 miles, doesn't appear to have been tracked. Clean.
Any thoughts on what else it might be? For context, car was apparently well cared for by the previous owner. Looks very new underneath with no road rash.
FYI - Pump sounds good with minimal valve train noise. Gonna update the heads soon regardless via AHP. LOVE this car. Wicked.
How many miles since the end-links were replaced? I had to do mine every 10k or so.
Did you check the latch for the hatch? Also, just guessing here there are bump-stops on the far right and left to adjust the hatch-to-body gap. Maybe raise them up so there is more tension and that may take out some slack. But too much and the hatch may not shut. Either way, if you add more tension and the sound goes away but the hatch is sticking up, then you are closer to fixing the issue.
Links have 11.6 miles on them . Replaced all four this morning hoping this would end the clunk. The hatch bumpers were close to proper adjustment. Used a dial caliper to adjust .05 down and hatch wouldn't shut. Backed off half and it shut. Thanks for the tip, I'm sure it will help. Are there exhaust hangers in front of the trans/diff that might be loose allowing it to jump? Feels tight but I am willing to try anything.
Links have 11.6 miles on them . Replaced all four this morning hoping this would end the clunk. The hatch bumpers were close to proper adjustment. Used a dial caliper to adjust .05 down and hatch wouldn't shut. Backed off half and it shut. Thanks for the tip, I'm sure it will help. Are there exhaust hangers in front of the trans/diff that might be loose allowing it to jump? Feels tight but I am willing to try anything.
Thanks!
I don't know much about noise from the exhaust that sounds similar to the hatch. I've had problems with the exhaust on more than one occasion with the C5 and C6, but I think the issue was a squeak noise that came from springs. The spring on yours may be completely broken?
There are a couple things you could do to narrow down the problem. Sit in the drivers seat and have someone gently shut the hatch and also unlatch it to compare the sound location and freqency to the problem sound.
If you could get your car on a lift, muscle the exhaust pipes forward and backward and then side to side. Jerk it pretty good to try and replicate the sound. That is how a chevy mechanic diagnosed a squeaky exhaust spring. I couldn't replicate the noise driving around with him in the car. He actually had me pull into an oil change pit and moved the exhaust to replicate and then isolate the noise.
It sounds as though you recently bought the car. It also sounds like you've pretty much covered the bases for the mechanical stuff. Has this car ever been involved in a rear end collision? The rear tub is glued to the frame. Everything behind the seats is connected to the tub. If part of the tub has become unglued it could sound like a loose hatch.
@C5 - Thanks - Can't get it up high enough yet to check the springs, however when I put a little more arm into a wiggle, I can hear them creaking. I'll grease em up when I can get to em soon. The wife is gonna drive me around while I (try) to lay in the cargo area and pinpoint the noise. I'm 6'7" and this will be a bit of a trick. FYI - Hatch bumper adjustment helped. I'll tweak them some more.
@stefuel - I did recently trade my '05 vert for this Z. I looked at the car extensively, looked at the Carfax (I know, but it's something), and local service history and didn't find any indication of a rear hit. I look at the parts relations to others for oxidation deltas IE, these look newer than those, etc and the rear setup looks like it's aged the same as the front. Alum control arms, subframe etc. Can usually see something newer than others in contrast. It looks really good under there.
That said, I'll get it on a lift and inspect the joints. Do cars that have separated joints have other adverse characteristics, like rear alignment, handling anomalies or bizarre effects under heavy accel? The car is exceptionally tight compared to my '05 vert and I thought that car was tight. What are the symptoms? Thanks for the reply
I'm embarrassed to say this, but will anyway. I spent a good two hours under the car looking for a source of something causing a clunk. Ended up being the stupid, upper hatch trim piece. It had popped out of place, plain as day and I didn't notice it.
I tried sitting in the drivers seat and had the wife close the hatch multiple times varying force. All good. Nice and positive without the clunk. Then asked her to drive me around while stuffed in the cargo bay with my head laying on the battery lid. Funny side note: She commented that when she has to kill me, she will have to tote my body in her Buick because the Z was not meant to have my oversize carcass transported like that. I told her to use my chainsaw and put me in garbage bags first, "Might want a 427 to try and outrun the law". Anyway, I opened the battery door and put my ear close. Definitely sounds like a muffler/exhaust part hitting another solid object on the RR. The LR sounds perfect. Going to try hose clamp compressing the rubber isolators on the hangers to restrict the inertia movement. They seem a little soft and "wiggly" as the wife calls it.
@Mike D - Thanks for the tip, mine is a little out of place also, probably on its way to making noise.
Going to try hose clamp compressing the rubber isolators on the hangers to restrict the inertia movement. They seem a little soft and "wiggly" as the wife calls it.
The wigglyness is by design, it needs to move a little so taking the play out of it would defeat the intent.
If the rubber isolator(s) are easy to remove and put back, consider inspecting it off the car for breakage/wear. Maybe do a swap and see if the origin of the noise changes to the LR if there isn't an obvious problem during inspection.
In the case where the inspection is good and the noise does not change from right side to left side after swapping the suspect isolator , it may not be the isolator that is the problem and the noice could be another hanger that is the problem further up the pipe(s).
I found the problem. I didn't think it would matter (or to mention) until today, at wits end. The clutch was replaced right before I bought it per the service records. While riding stuffed in the back, I did notice the clunk/pop seemed like it was slightly after the bump in the road. Figured the muffler/exhaust was hitting on a spring back. No matter what I did to the exhaust system, I couldn't get it to hit anything. So I got out my trusty Starrett 6" scale and started poking around joints/interfaces for gaps. Low and behold. They didn't tighten the trans/diff sub frame nut on the AFT RR. Tightened/torqued/checked all 4 main carrier nuts (I can only see 4...), took the clamps off the muffler isolators and backed off the tension (some) on my hatch and problem solved.
Begs the question... what else is not properly tightened/torqued. I need a lift...
Thanks for all the tips and help guys. This forum is great.
Good thing for your persistence!! Its good to hear the follow-up.
I had the right rear A-Arm come lose at 136 MPH during a turn. That was the scariest moment of years and years of HPDE's, no question. Shoddy mechanic from Speedware motorsports in Redmond, WA.
Good thing for your persistence!! Its good to hear the follow-up.
I had the right rear A-Arm come lose at 136 MPH during a turn. That was the scariest moment of years and years of HPDE's, no question. Shoddy mechanic from Speedware motorsports in Redmond, WA.
A long time ago a local guy around here lost his C5 Z at the track due to a VERY well known (and still) respected shop - they didn't torque the camber adjustment bolts properly, it slipped mid-corner and sent the car into the trees. At least the driver was ok, the car was not..
Needless to say that shop owner NEVER forgot the event, still has a print-out of the Tq. specs for Corvettes on his tool box.
Last edited by Dan_the_C5_Man; 08-16-2016 at 06:17 PM.
I had the right rear A-Arm come lose at 136 MPH during a turn. That was the scariest moment of years and years of HPDE's, no question. Shoddy mechanic from Speedware motorsports in Redmond, WA.[/QUOTE]
Glad you didn't get hurt. A change of underwear and a shot (or 5) of stiff bourbon was in order after that I'm guessing. Just reinforces why I generally do my own work. Not that techs are bad guys, just make expeditious mistakes that, in my case are extremely annoying or in your case, down right terrifying and costly. Sadly, they will never work on my car again. It's like taking the wife to a new restaurant. If the food sucks, we smile, pay the bill and never return. If it makes us sick, I visit the next day for a "direct" conversation with the manager. I hope Speedware got a strong flavor of your dissatisfaction.
08-13-2016, 05:47 PM
Clunk over bumps
. Replaced all four this morning hoping this would end the clunk. The hatch bumpers were close to proper adjustment. Used a dial caliper to adjust .05 down and hatch wouldn't shut. Backed off half and it shut. Thanks for the tip, I'm sure it will help. Are there exhaust hangers in front of the trans/diff that might be loose allowing it to jump? Feels tight but I am willing to try anything. 
Good catch...
Glad you didn't get hurt. A change of underwear and a shot (or 5) of stiff bourbon was in order after that I'm guessing. Just reinforces why I generally do my own work. Not that techs are bad guys, just make expeditious mistakes that, in my case are extremely annoying or in your case, down right terrifying and costly. Sadly, they will never work on my car again. It's like taking the wife to a new restaurant. If the food sucks, we smile, pay the bill and never return. If it makes us sick, I visit the next day for a "direct" conversation with the manager. I hope Speedware got a strong flavor of your dissatisfaction.