Vibrating Violently

In defrost mode your A/C is turned on on dehumidfy cabin. There maybe something a miss with idle up or compressor. Try A/C operation see if it shakes.

I had the same problem with my 03 Cavalier last winter. I had drove my car for a half hour so it was good and warm. Then I parked it for 15 minutes. When I got back into the car and started it, the whole thing just vibrated. So I turned the front Defrost off and it stopped. On my way home I tried to turn it back on a couple of times but it kept vibrating. The next morning it worked fine. I have only had this happend twice to me. This winter has been a lot colder than last year, and I have not had the same problem.

When my cav did that I had to replace the A/C compressor. My mechanic said it was falling apart inside making is work too hard.

I have a 2002 Chevy Cavalier Coupe with the 2.2L SFI motor. Only during acceleration, there is a loud rattling, vibration noise coming from somewhere in the engine/dash area. I have also noticed that when I am on the highway or there are high winds, I can hear a rattling noise coming from the same area. It almost sounds like a bolt rattling around in the defrost vent. Don't know if the two are related? But the engine noise during harder acceleration, about 3000-3500 rpms and above, is the bigger issue, as I don't want to be hurting the motor. Thanks

Hi:
Have you checked the heat shields on the exhaust?

Hi, one of my first instincts too was the exhaust. But there arn't any heat shields by the exhaust manifold or really anywhere in the engine bay. There might be one farther under the car, but I don't think that could be it do you? Thanks for your help

Hi:
I would recommend checking it anyway. let me know what you find.

Joe

Hi, I got under the car and inspected everything pretty well. I checked every heat shield and they all seemed firmly in place.

I have also read something about a timing issue. Do you think this could be the problem?

Also, there was something about a engine mount. But that seems like a pretty severe problem that i would have noticed.

Thanks for your ideas.

Two issues, which I feel are related:

1.The car seems to struggle with acceleration around curves, and the engine sounds labored.

2. The car begins to vibrate excessively at 40 mph, and vibrations increase as speed increases.

Is this unsafe, or merely a factor of the car's age an mileage? What could be causing this problem?

A mount has a rubber cushion that can go bad allowing metal to metal contact; thus you feel drive line vibration throughout the car. That would be my guess. Here is a test you can try.

Put the park brake on, open the hood, and start the engine. Next, have a helper put his foot securely on the brake and put it in drive and give it a little gas. Watch to see if the engine lifts excessively, More than an 3/4 inch is excessive. Also try it in reverse. If the engine seems to lift more than I mentioned, check the mount responsible for that area.

Let me know what you find. Also, don't stand in front of the car. You never know if the helper is mad at you. (LOL)

Joe

Does it struggle accelerating uphill or any other time? Have you had the tires inspected to see if there is maybe one coming apart? Possibly out of balance?Try rotating them front to back and see if it changes anything

Hi, I did the test and the engine movement wasnt excessive to me. I would say it didnt move more than 1/2 inch at the most.

Any other ideas? Thanks again.

Hi:
Without being there to actually check it, the only thing I can think of is even though the mounts are not broken, I question the rubber mounts on them.

Hello,

My car has recently began to vibrate at high speeds, (Around 100km/hr) the alignment looks good, and the wheels are in excellent shape. The car drives well at low speeds, but once i hit the highway it vibrates, i feel it in the steering wheel and the gas peddle.

Any ideas?

P.S. i live in Canada and we just had a wicked snow storm last night, i drove in in last night and the car was fine, but the day afterwards it begins to vibrate.

Your last sentence seals the deal for me....maybe ;-)

Get it thawed out or get the snow and ice out of the rims as they are causing temporary wheel weights to throw the wheel out of balance.

Thanks Paul,

I drove it earlier in the day when it was milder out the car was fine, but when the sun set and the temperature dropped thats when the car began to vibrate at high speeds. Do you still think it's the ice?

Also after your suggestion i cleared all the snow and ice from the rims, and checked the tire pressure. Although this helpped a pit, it still vibrated.

Another symptom is when i go to even higher speeds, say 120km/hr it continues to vibrate, however when i return back to 100 the vibration lessens. Around 85km or less there is no vibration at all.

We had a car in the shop last week that was in the heated area for an hour. Some of the ice/snow melted and shifted down. We finished with our work, test drove it and parked it. The mixture refroze and a vibration was present. Back in the shop it came and the rims needed to be thoroughly defrosted.

Think of how heavy one oz is....not much. thats all it takes to give a vibration and there is probably more than that on the rim in ice weight unless the rims have been completely defrosted.

Wheel vibration from unbalanced rims are most prevelent at higher speeds such as yours.

Never say never, but 90% sure this is the case.