Just bought a 95 six speed with 32K miles that has a couple of problems:

- a constant humming vibration coming from the rear of the car at 65+, any gear, engine on or off, a/c on or off, clutch in or out. Doesn't feel like a tire balance issue. Guessing at at u-joints but doesn't seem right for a car with 32K.

- Both windows roll up too far. If you open the door and roll the windows up all the way, the front of both side windows roll a good 1/2 inch higher than the back (1/2 inch of non-tinted glass showing.) If you go to shut the door the top/rear of glass is tilted back so far it bounces off the paint. Really weird that this is occuring on both sides to the same degree. Also, with the door open and the glass all the way up you can rotate the glass around in the door more than what i call normal. My guess is that it is the whole regulator assembly. Will check it out when i go to replace outer window seals.

Anybody have any problems similar to these and what did you do to fix?

 

I get the same humming sound...a lot of C4s have that defect...
I did a tire balance and it helped.
Even if the tires are nearly new, tire wear throws the balance off.
As for the window stuff i've never heard.
I know one guy that bought a 96 auto in mint condition supposidly and later on found out that the car was in a major accident. As soon as he found that out he had trouble getting rid of the car, the under carriage showed the bad news.

 

My first reaction was an accident. Get a carfax. :cheers:

 

Humming at 65+ could be a bad wheel bearing, jack up the rear and give each wheel the 12 & 6 shake test.

 

I believe there's something in the tech tip on window adjustment so maybe that can fixed without too much trouble. I have a 95 also and I have some vibration/humming at around 3000 rpm that I can't figure out either. It also does it at around 55-60 mph so maybe it's balance.

 

I'd be willing to bet the window problem is a broken window guide stop. When you roll the window up, the rear of the window has a metal bracket that fits into a mating cam, and that determines how far the rear goes up, as well as setting the tip-in angle (to some extent) and keeping the window from flopping around. On the front the same idea is used, although they use a cheap plastic tab bolted to the window glass, and this tab hits a metal stop tab at the top of its travel to keep the front of the window glass from shooting out the door. When the plastic tab on the front of the glass broke on my car, the front of the window came up an extra 1/2 inch, so that it overlapped the weatherstripping in the windshield pillar.

You'll need to go into the door to find out what's really going on, but I bet that's your problem. And no, it's not unusual to have this problem on both sides. When you see how flimsy those plastic guide stops are, you'll understand.


[Modified by HammerDown, 11:14 AM 7/23/2003]

 

Thanks HammerDown. I'm going in this weekend. Will let you know what i find.

 

FYI -

Don't forget that the driver's side window has the "Auto-Down" feature. So when you have the panel off and are rooting around near the regulator, raising it up and down with the switch, don't put your hands or anything else under the "scissors" of the regulator. Press the switch down and the window may go down all the way, very quickly. And trust me, if that thing comes down on your hand or arm, it hurts VERY VERY much.

 

As for the front coming up too far, that is definitely the Drivers side upper window guide stop. The part number for it is 10243037. Pass side, I'm not sure. My window wouldn't go down - then I heard a SNAP - then it went up too far.

To get to it, you'll have to take the trim panel off. Two phillips screws just rear of the window/mirror switches in the little hand hold depression. Take a flat bladed screwdriver, place it behind the plastic door lock slider (the thing that moves when you hit the lock switches) and pop it off the rod. There's a phillips screw behind that. There's one behind the door handle, too. Take the flat bladed screwdriver, slip it in the top edge of the light just above the handle a half inch in on either side, and push down until the light assembly and light pops out. Slide the plastic bezel for the area forward, clearing the door lock rod, and out.

Slide your fingers up under the plastic door panel at the bottom and pull out the five round, flat push pins. The door panel is almost ready to come off, but you need to disconnect the hatch connector, then pull up the window/mirror/handhold panel and take off the mirror connector and the window connector (the hardest one to get out - slip the tabs on either end up with a flat screwdriver and get the other two on the side by hand).

Now, you are looking at a sheet of insulator. Remove it, you can tape it up later. Behind that, metal inner panel. Theres a half dozen or so 7mm bolts that hold the inner mounting panel on, along with some 15 torx's on the back by the tire information sticker. After those are off, you can push the panel back a bit and work with the window switch to get the guide stop bolt in a desirable location. Pull out the pins that route the wiring alongside the bottom, that'll make things easier. The guide stop is towards the front - to see it, push in the window connector just enough to make a connection, and raise the window about 60-70 percent up. Look just forward of the edge of the inner panel, and you should see a bolt in the window glass. The plastic piece around it is the guide stop. Mine was cracked and broken. To get it out, you'll either need a special tool from GM, part number (runs to garage for service manual) J22055 door window roller nut socket. Or, you'll have to take the glass out completely, I went this route. To remove it, first you should scribe the location of the window pads, then loosen the bolts that run along the top of the door panel close to the window. Then fiddle with the window switch again until the window nuts appear through the holes cut in the metal inner mounting panel. Remove both of them. Scribe the location of the two 10mm regulator bolts that are shot on the back half of the door mounting panel - you can't miss them, then loosen them. Make sure to have your fingers behind the panel holding the scissors up, or it will fall down into the door. Twist it around to remove it through the hole. Pull the window out, lift it up (carefully) and use the three openings on the inner edge of the door to pull the studs through cleanly. Now, put the window on something soft, put a needle nose pliers against the metal circle with the two holes, and unbolt the guide stop. Now's a good time to windex the sucker down. Put the new one on, install is reverse of removal.

Now, about the back edge being out of whack? That's the job of the scissors - the metal thing with the two 10mm bolts. Remember the scribing you did? Move the scissors a little forward of its marked location, bolt it down, then put the window up. Adjust as needed.

Estimated time - 1.5 hours for first door, 45 minutes for the second.

Take your time, make sure everything is in order, and be careful of that one-touch down feature!

Let me know if you have any problems.

 

Guys.... still working on the vibration. Did the 6 and 12 test and found some looseness...maybe 2-4mms in and out at the top on both rear wheels. Is this indicative of bad wheel bearings? hard to believe at 32K!!!! Am planning to loosen and retorque the big nut. Haynes says 164 ft/lb for all cars 84-96. Wonder is that value is really good for my 95. Any comments will be appreciated....

 

If the wheel bearings are bad, you will eventually hear them. It's really hard to mistake bad wheel bearings. One easy way to tell, if you drive it long enough, the wheel bearing will get worse and worse and eventually, there won't be a doubt as to whether or not it's bad. A little bit of play is normal, though.

What kind of tires do you have? If you know someone else with 94-96 wheels that might let you swap out the rears, try that and see if it goes away. That would eliminate a rim/tire issue.

At this point I'm thinking it might be related to your differential. You might take it to a mechanic for an inspection, or just drain the fluid and replace with new fluid plus two bottles of GM limited slip fluid.

 

Stormy652....thanks for the window instructions, they helped out alot. I pulled the window on the drivers side replaced the stop and then found that i couldn't get the window back into the door. Stop on window is too wide. I removed stop, installed window, and then installed the stop using channel locks holding the big nut/disk on the back side of the glass. I knocked out the passenger side in about 30mins using the channel locks.

thanks...

 

I'm wondering why such a low mileage car has these problems? My '95 has 119,000 miles and nothing wrong(knock on wood).

 

For real a car with that milage shouldn't be making any noise..