2.5Turbo Posted May 3, 2010 Share Posted May 3, 2010 My 02 Outback wagon with the 4EAT emits a recurring, random chirping noise when accelerating. It seems like it does it from about 20mph up. Does not do it when coasting or engine braking, nor does it do it when loading the drivetrain in gear with the brakes applied. At first I thought it was belts, but I took both off and drove around the block a few times and it still chirped. FWD fuse doesn't change it either. If it helps I'm also trying to track down a vibration that occurs between about 20 and 30mph on acceleration; think it might be a DOJ going bad. The frequency of the vibration seems to be about two times the rotation of the wheels, which is kind of weird. Also doesn't go away with the FWD fuse in. I put a video up on Youtube to assist with the diagnosis: All but the first five seconds or so are driving uphill. You kind of have to listen for it, but it's there. Excuse the taken apart center console...I'm in the middle of installing a ham radio transceiver in there and it's not quite buttoned up yet I'm used to working on diesel Mercedes so Subarus (and AWD cars in general) are relatively new territory. Any ideas? Link to comment Share on other sites More sharing options...
nipper Posted May 3, 2010 Share Posted May 3, 2010 It is more of a whistle. The biggest cause for this is a loose air cleaner, or somehting leaking or loss in the air intake system. What happens under WOT like getting on a highway? Link to comment Share on other sites More sharing options...
Fairtax4me Posted May 3, 2010 Share Posted May 3, 2010 I don't know if I heard it or not honestly, but I've got a few ideas. Have you check the brake pads? When was the last time new brakes were put on and what brand of pads and rotors (if they were replaced) were installed? Can you still hear the noise with the windows closed? Could it be something in the glove box or under the dash loose or rubbing on something only when a certain frequency of vibration is reached? A vibration or shimmy at speed could be due to several causes such as tire balance, worn U joints, or a worn drive shaft carrier/support bearing and or bushing. A worn carrier bearing/bushing will often clunk repeatedly or give a wobbling feeling during hard acceleration from a stop. This can also be a sign of a bad U joint. It could also be a half axle out of balance, or a worn cv joint. Usually a bad cv joint is accompanied by a clicking or knocking sound under acceleration in tight turns. These may not cause the squeaking you are trying to track down directly, but may be causing it through vibration traveling through the framework of the car. Link to comment Share on other sites More sharing options...
2.5Turbo Posted May 3, 2010 Author Share Posted May 3, 2010 If you're having a hard time hearing it, there's a pretty good squeak/chirp half a second before the 1:00 mark, then they're more noticeable between 1:12 and 1:20. If you're able, it helps to turn down the bass when you're listening. The car does need a brake job, the rotors are not in the best shape (wobble when braking at high speed). The noise is definitely outside. I can hear it a bit with the windows closed, but the fact that the noise reflects off guardrails tells me it's coming from somewhere outside. The vibration only occurs at certain speeds, and only when the drivetrain is relatively loaded (accelerating or maintaining speed on a hill). It does not vibrate or squeak when coasting in neutral or in gear, nor when engine braking down a hill. Also not there when revving in neutral. The squeaks/chirps aren't always accompanied by the vibration; the squeaks happen from about 15-20mph on up (road/wind drowns them out above about 45), while the vibration is only between about 20-30mph. My air box is pretty well sealed and secure; I can put my hand over the intake pipe and it will create and hold vacuum in the air box. Both hold down bolts and all clips are tight. The noises I'm hearing are very quick chirps, not a continuous whistle. The squeaks don't get worse as I give it more gas, they seem to subside a bit or get drowned out by the engine under heavier throttle. I did take off the heat shield this evening and pushed and pulled on parts of the driveshaft. No noticeable play in the U-joints, but the rear joint as well as some spots on the shaft itself were rusty. The carrier bearing seems to turn OK, but there is a good amount of radial play in the rubber bushing. The rubber seems to be in good shape, it's just easy to move around. Some photos of the driveshaft and U-joints (I squirted some oil in the joints to see if they were squeaking, didn't change) Front joint Front side of the carrier bearing Rear side of carrier bearing Rear U-joint Link to comment Share on other sites More sharing options...
nipper Posted May 4, 2010 Share Posted May 4, 2010 My car whistles (chirps) only at specific points and not all the time, so do not rule that out yet. The vibration can be the fact you need brakes. Fix the brakes first before we start using scattershot to try and diagnose it. Could be a warped rotor, an out of balance wheel, a broken belt in the tire. Move one tire at a time front to rear and see if it changes. Even if the tires are brand new you can still have a seperated belt. nipper Link to comment Share on other sites More sharing options...
2.5Turbo Posted May 4, 2010 Author Share Posted May 4, 2010 The reason why I think it might not be brakes/tires is because the frequency of the vibration is higher than the rotation of the wheels, probably at least two times the wheel rotation. I'll get the brakes done soon and we'll see what happens when my mechanic looks it over. Link to comment Share on other sites More sharing options...
nipper Posted May 4, 2010 Share Posted May 4, 2010 The reason why I think it might not be brakes/tires is because the frequency of the vibration is higher than the rotation of the wheels, probably at least two times the wheel rotation. I'll get the brakes done soon and we'll see what happens when my mechanic looks it over. Could be a tire and a brake, both brake discs out of round, a wheel beainrg etc. Lets rule out things we know are bad, and go from there. Link to comment Share on other sites More sharing options...
Fairtax4me Posted May 4, 2010 Share Posted May 4, 2010 So does the noise increase in frequency as the car increases speed? Does your car have plastic wheel covers? I noticed since it has gotten warm (riding with the windows down) that my car makes a weird almost quacking sound when driving. It's there at all speeds as far as I can tell. Hard to say above about 45 because the noise of the road and engine drowns it out. I had a friend listen while I was driving the car across the parking lot and he deducted that it was coming from the wheel covers. Sure enough, popped them off and the noise went away. Put them back on, there it was again. Kinda strange, but might be worth checking. On a 2002 though, you probably have aluminum wheels. Brakes can squeak multiple times per revolution even if the rotors are in perfect shape. All it needs is a spot just ever so slightly higher than the rest to rub against the pad to make a noise. It's usually worse if the pads are down to the squeal clips (wear indicators). Link to comment Share on other sites More sharing options...
2.5Turbo Posted May 4, 2010 Author Share Posted May 4, 2010 I've got the stock alloys. As speed increases, the squeaks seem to become more frequent, but the sound isn't cyclical in nature like a brake squeak. Brakes are silent otherwise. If I simulate a heavy load and try to accelerate while lightly applying the brakes the squeaks occur just as if I'm climbing a hill. Link to comment Share on other sites More sharing options...
nipper Posted May 4, 2010 Share Posted May 4, 2010 Brake discs slightly flex, ever so slightly when torqued. Normally its not an issue, but if you have an out of round disc, worn brakes, and the moon is in the sign of Libra, it can cause a squeek. nipper Link to comment Share on other sites More sharing options...
johnceggleston Posted May 4, 2010 Share Posted May 4, 2010 i had a rear caliper that would hang up, the slides needed to be re-greased. but after certain braking situations it would drag and chirp. in addition to needing grease the rotor was warped. anyway, if i applied the brakes very slightly it would eliminate the chirp. Link to comment Share on other sites More sharing options...
nipper Posted May 4, 2010 Share Posted May 4, 2010 BTW it is not ujoints. They start at higher speed and start working down (shows up at 75, then 70, then 65, then 60), clunk, or really vibrate at all times (thier death moans). nipper Link to comment Share on other sites More sharing options...
2.5Turbo Posted May 15, 2010 Author Share Posted May 15, 2010 Brake job's done, new pads and rotors and the brakes are butter smooth now, but everything else is still the same. Also had a coolant flush and diff service done. I asked what he thought it was and he said he couldn't find anything on the lift. At first he thought the chirp was heat shields (drove around with him for a while to listen to it), but all were sufficiently clamped and secure. He also thought the vibration might just be inherent in the engine combustion, but I don't think that's the case because it isn't RPM dependent and hasn't done it the whole time I've owned the car. I'm about ready to take it down to the stealer and have them drain my wallet... Link to comment Share on other sites More sharing options...
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