Shadec5

Picked up a 2002 coupe, 58k miles, tires about 8 months old about 300 miles. Drove it home 4.5 hours. At 65 + I feel a rhythmic vibration in the seat. Steering wheel is smooth. Vibration is about a half second then smooth for half a second, very consistent. Tire pressure is good. Do you all think a balance issue? Maybe shocks? Kinda odd to me how it is rhythmic. Also, can I take it to my local Goodyear shop? I know there is a certain way they need to lift it. I have had a few c3s in the past but I had a vette shop close. No vette places near me now. Thanks for the help.

Dads2kconvertible

My 2000 is doing something pretty similar. Noticed the other day the wheel weights are no longer attached to the pads stuck to the passenger front wheel. So I suspect that's the source of my vibration.

SilverC5guy

Same thing on a 99. It gets a little better as it warms up. Also where is that anitfreeze smell coming from? Its under the hood and it does not leak any. New hoses,water pump,radiator, recovery bottle and cap basically everthing thst has anit freeze in it.

xcarter

Anytime something hits at speed I think tires first. Could try sitting in the driveway and hold the throttle at the same revs you'd be at at 65+ for bit. That would tell you if it's one of the belts or balancer that spin when the drivetrain isn't working.

jim993

Get a good balance of all four wheels/tires. Make sure the tech watches each for out of round tires or bent wheels. Tires on bent wheels can be balanced but still cause a vibration from out of roundness.

SilverC5guy

New tires and wheels and it didnt change anything. Also replaced the balancer along with basically the whole front of the engine. It did it with the wagon wheels and the Z06 17&18 and 18& 19 now. I am wondering if its not in the torque tube, maybe the couplers?

jim993

New tires can be and often are, out of round. Wheels checked for runout before mounting tires? Tires checked for runout after mounting?

SilverC5guy

No and no, I just find it hard to believe that 4 different tires and nothing would change. I have zero shake in the steering wheel, its still in the exact same spot and still improves after driving for 30 minutes or so. Something is getting warm and exapnding with heat to improve it.

PerryKing

Mine does exactly the same thing. Get up to speed and it has a slight vibration for about 2 seconds then quits, 2 seconds and quits. I’ve never known a tire or wheel vibration to be rhythmic. Typically you reach a point or speed and the vibration holds. I’d like to figure it out but it’s never bothered me enough to spend any time looking for it.

Toys4Life C5

I triple this. I have had a minor version of this for years and through the years, I have replaced all 4 tires (due to normal wear) and when replacing the tires they are all evenly worn. I also have replaced the clutch and PP to a twin disc for more performance. So, as far as the vibration goes - I am stumped - but it is so very minor I don't bother searching further. If it bothered me enough, I would have the alignment checked by a highly skilled alignment specialist.

SilverC5guy

Agreed, it hasnt been bad enough (or gotten worse) over the years to really be a concern. It may be a quirk they just have. This anit-freze smell however, really bothers me. lol

PerryKing

Is the coolant level low? Is your oil discolored? Do you only smell it when the car is up to temp? Have you really looked over locations that could leak for signs of coolant? All the hoses, water pump, tank, base of the heads? Do u smell it with the heater on from the vents?

corvettezman

I have this as well. It gets better with lower tire pressures. Not sure what it is either.

c5arlen

It's coming from the rear? ... Perhaps the axel bearing, right or left wheel... Listen as you drive and sway the steering wheel right and then left.. That will tell you right or left axel bearing is kaput... Replace both right and left axel bearings.... About 300 bucks... You don't want that bearing coming apart at speed! That will STOP rear wheels immediately!... You can imagine the outcome from that!

SilverC5guy

All new silicone hoses, water pump and radiator. New coolant recovery tank and cap. Never smell it inside the car, even with the heater on. No anit-freeze in the oil (ever) and it never drops the level of oil or anit-freeze. Use Mobil 1 oil and Dex cool. Never see any on the ground (oil or anything else for that matter). Only smell it after I drive for a bit and put it back in the garage. Almost like it vents it out after I shut it off. I have had this car over 2 years and still have yet to find the smell.

SilverC5guy

It's not a wheel bearing nosie, I am a retired tech and it's harmonic, not constant. Its something that goes out of balance and then comes back, repetably.

Toys4Life C5

This makes me feel better about myself that I have not figured it out.

Vetteman Jack

Moved to C5 Tech.

corvettezman

My tech suggested today that I briefly put the car in neutral and let it coast when this happens at about 70MPH and see if that makes a difference. Not sure where he's going with it, but I am going to try it. Has anyone with this problem done that ?

Johnny Hardcore

vibration in the seat is typically caused by rear wheel issues or hubs. I had a similar issue occur when I swapped all four tires that aged out. I didn't have any vibration or issues with the old tires. Car drove and rode true to over triple digits. They were just too old.

Although balanced to 0 the new rubbers exascerbated vibration from a slightly bent rear wheel. I had the tires remounted and balanced but still had the issue. Always over 65mph and worse on some streets than others. Making it intermitent vs. constant (paving contingent).

Swapped wheels with another OEM set (and although one of the rears in my replacement set was also slightly bent) the vibration went away completely.

Some tires just mate better to some wheels.