Hi Guys,

Today was the first time I really drove the Sunfire GT. I purchased this car in Chicago after driving it about 200 feet in a apartment complex parking lot. The car was running on battery only because the alternator did not work.

I got it home changed the alternator, the starter, did a big three ground install and plugs. I went about 20 blocks in it today.

So, the good news:

My first time driving a quad 4 and a much stronger engine than I would have imagined! very torquey!

Nice calm idle with no vibration coming from the engine (I actually thought it had died a couple times, but it was just running smooth!), not burning or leaking any oil at all that I can see!

Now The bad news:

Tranny feels nice to about 25 mph then I start getting a harmonic sort of vibration underneath my left foot. This is definitely coming from front driver side!

Hitting 35 mph the vibration is pretty bad and at 40 I can feel it in the heel of my right foot.

It sounds like something turning very fast that is very out of balance

If anyone has ever driven fast in studded snow tires without snow, that is about what it sounds like at 40mph..

The brakes are completely shot but do not think it is causing this problem.

Possibly a very bad CV Joint? Maybe a bad wheel bearing?

I am hoping so, otherwise it is probably the tranny!

...thanks...gary

Oh what the hell! If it were your wheel bearing you would be hearing it. Trust me on that one! My brother and I, along with probably most every other person on this forum have battled the stock GM wheel bearings. It would make a growling noise when turning. Maybe a mount??? I haven't heard of a CV joint goin bad on these cars unless the boot is torn and leaked out all the grease. Tho I drove on a torn boot with no grease for a good six months and never had an issue. Did you pull the motor without the tranny? Maybe you tweaked the intermediate shaft to the passenger side a lil too much?

No, no motor pull on this car though it seemed like it as long as it took to do the starter/plugs/alternator.
And I am hearing it, it is not squalling, it is vibrating all the way through the sheet metal. It actually starts as a low hum and builds
to a very loud hum. Seems to be worse when you are backing off more than when you accelerate. All of this noise happens when you go in a straight line.
and always starting at 25 to and bad 40 mph.

I have not paid much attention to what it sounds like on turns, was too busy trying to figure out the buzz from 40 mph.

Although the engine sounds so good, maybe I just like the way it sounds when accelerating! I dont know if I trust my 18 yr old with this car or not!

You think I may have a motor mount problem and that is where my vibration is coming from?
If so, which do I change? Can I look at it and see a problem if I have one?

thanks...gary

Check lug nuts.

Might sound stupid, but if you just got it, maybe the guy had just put new wheels/tires on it... they could be loose. If they lugs are loose, you will have that exact problem.


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I don't practice what I preach, because I'm not the kind of person I'm preaching to.

I will check out the lug nuts and then examine the motor mount today to see if I can judge condition...thanks..gary

The upper motor may be loose, I doubt that one would be torn. The lower dog bone mount may be torn. Also, being that you said you feel it coming from the clutch, you might wanna check the tranny mounts as well. There are two of them. Make shure everything is nice and tight as well.

Thinking about it, if it were a CV joint, you would feel it in the steering wheel.

You get a lil more than you would expect from a N/A 4banger, eh? Its a fun car! Fairly easy to werk on as well.

Yea, this little thing is a beast. I was shocked. The gearing really climbs at low speeds also!

This is a 3 speed auto tranny. When the vibrations start, they seem coming from below the drivers left foot or
front/left from the left foot area.

Is the lower motor mount on the firewall side of the engine?

Can I visibly see a problem if I have one?

Thanks...gary

possibly a bent rim?

You can plainly see the top mount on the passenger side, next to the coolant reservoir. The lower mount is right behind the passenger's tire.

The tranny mounts are on the driver side. Not shure of the positions for the autos, there are two of them tho.


I was also thinking along the same lines of MMartin but thinkin maybe you have an off balance tire. Swap out tires and see if you notice a difference

Well the wife had to have Klondike bars so I put the car in the air and switched the front wheels.
This made no difference at all, the noise stayed on the left side of the car.

While I had the wheels off, I had a look around. The boot seems to be intact on the CV Joint.

The left rotor is harder to turn than the right with the automatic tranny in neutral.

I didn't get any noticible side to side rock on the tires when they were in the air and tight on the lugs.

I purposely took a couple turns hard to see if I got any noise from the wheel bearings, but there was very little.

I forgot to look at the mounts and will have to do it in the morning.

The car had sat for 6 months before I got it. So I thought there was a chance that the calipers were siezed and
the pulsing harmonic high pitch sound was the rotors glancing on the pads.
If that is the case, the left is siezed pretty good because I tried braking at 40 mph with my foot on the gas to see
if the noise went away and it did not.

I am going to change rotors, calipers and pads right after I change the transmission fluid. That is next.

thanks.....gary

maybe just try swapping the right side rotor to the left see if the problem persist's if it does dont go spending money on new rotors

Hi Guys,

I put the car up on stands tonight. I examined all of the mounts, the top mount on the right, the dogbone on the lower right, then I found a single mount for the tranny behind the left wheel.
I had to remove the inner wheel well, to check out the tranny mount, but all the mounts looked intact.
Does 2 motor and 1 tranny mount seem right for a 97 sunfire gt?

The brake pads were crap. The left outer pad was almost gone on one end, the other end of the same pad was nearly 1/4 " wider.

So my son and I went ahead and pulled both of the calipers. I can replace these for 15 bucks exchanged and the rotors are
30 (go figure, the calipers less than the rotors).

I guess I could turn the rotors, but I do not know the minimum width and the calipers are so rusted, the dimension that is supposed
to be on the inside cannot be read.

Anyone have this dimension? My rotors mic'ed at .725". They are heavily rusted, I may be better off just to replace them...thanks...gary

since you said you havea 3 speed auto.. you definitly dont have a quad 4... you have the 2.2 ohv pushrod 2200.

you can also have someone push on the brakes and see if the calipers are doing their job. ever think of the wheels themselves bein unbalance?

My mistake, Sunfire GT, 4 speed auto, definitely the Quad 4...gary

I swapped the wheels, problem stayed on the left...thanks...gary

ah ok .. i still say get the wheels balanced. but seems like you have a mystery problem. bearings would make a growl, could possibly be the rotor itself.


using my 99 jbody manual the rotor specs are

minimum thickness after refinnish ... 30.6mm or 1.205in
discard thickness. 30.3mm or 1.19in
new rotor thickness 32mm or 1.26in

just replace the rotors, they are cheap enough. I can't imagine its only got one mount. Tho I can't say for shure. On my getrag there is one towards the front, and one near the firewall.

It it still up in the air, I will look again tomorrow.
the dogbone is the only motor mount on the bottom?
thanks...gary

AZ24Ncav wrote:ah ok .. i still say get the wheels balanced. but seems like you have a mystery problem. bearings would make a growl, could possibly be the rotor itself.


using my 99 jbody manual the rotor specs are

minimum thickness after refinnish ... 30.6mm or 1.205in
discard thickness. 30.3mm or 1.19in
new rotor thickness 32mm or 1.26in

Man I am going to replace these rotors for sure. I am 1/2' under your minimum!...thanks....gary

haha i got these numbers from the service manual. better get those done haha

Hi,

Wheel imbalance would come screaming through the steering wheel and entire body, not through your foot. I really suspect a bad motor mount. When the car is driving the the drivetrain is under torque things are moving about and something is contacting the body. Look for shiny spots that would indicate contact.
Take a pry bar and try to move the mount about a bit. Often at rest a bad mount looks absolutely fine and then comes apart as you drive and put stress on it. Shut oft the car and the mounts settles back to where it belongs.

Dave

Quote:

Hey man, yep just two. 1 mount on the drivers side with 4 bolt holes. The other mount on the back of the tranny closer to the passenger side axle.

-WHITECAVY

Bought new rotors, calipers and pads tonight, will be doing assembly within the hour.
the guy at AZ screwed the ticket up and I was there for an hour trying to straighten it out. He finally
just got cash out of the drawer and paid me. It was a mess, epecially for him when he trys to explain
the screwup and the bad drawer to the boss....gary

lol to the popcorn.

Let us know how you make you with the change and the test drive.