Noise from 40-70

[armbldgco]

Have rebuilt a 2003 G35 cope that was wrecked. The damage was mostly dead center in front but the car obviously went over a curb or something as there scrapes under the L rocker panel just behind the L front tire. When I reassembled the car and took it for it's first test drive, the original 17" factory wheels and tires were still on the car. At around 40 mph, a slow methodical noise appeared. This noise is accompanied by a small vibration that can be felt mostly in your feet and butt. The vibration is very slight but methodical. Both the vibration and noise speed up as the car speeds up. Again, it's slow and consistant.

I thought it might be the tires. I upgraded to some 2008 G37 factory wheels and tires and nothing changed. No vibration in the steering wheel. The steering wheel is not dead center when the car is going straight. Last night, I noticed that when turning the wheel to the right a little makes the noise go away some. At 70mph, the noise and vibration disappear. Anyone got a clue?

Thanks! -JIM-

[zozoka1212]

I can think of 2 things. alignment since the car was hitting something. Most likely sometihng is off. The other would be the engine mount. Where the engine sits. If one of them broken it can give you some wibration and sometimes when you floor it can be a little loub bang too.

Maybe somebody else has better idea.

zozo

[tollboothwilley]

My guess is alignment is off...and won't get much better if you have a control arm that is bent. If they hit a big hole/curb then that is a likely cause.

Also, possible culprits

transmission MountsDriveline - u-joints (i've had a car have similar issues at these speeds from the u-joints)

[silverbullit05]

well my experiance with this type of noise when im test driving cars i have found that slight vibration and noise that speeds up has something to do with something rotating. my educated guess would be start with the wheel bearings, or half shafts. normally if you turn left its the bearings on the right and vise versa. but before you take these into consideration make sure nothing is bent and get an alighnment