Another Noise, 99 OBW

If you have somebody listen closely while you reproduce the noise, can you isolate whether the sound is coming from the speakers when the radio off? Try tuning in a station on the AM band of your radio and see if you hear the whine any more / less and if it corresponds to your accelerator.

When was the last time the plug wires were replaced? A faulty wire(s) may cause a whine in the speakers and a bit of hesitation.

You don't mention the mileage, or much of anything else about the car. Any service done to your vehicle lately?

Have you received any indicators from the check engine light, brief or otherwise?

~Brian

Good post. I was trying to figure a way it might be heat shilds buzzing. Perhaps with worn motor mounts, under higher load situations the exhaust system flexes enough to start some heat shield to vibrate?

Carl

Good questions, I'll try to answer them as best I can. 145,000 miles on this beast. There is a heat shield buzz, one that took me nearly a month to locate. Right at 1500 rpm it buzzes annoyingly. I ended up stuffing steel wool onto the gap between the exhaust and shield in one spot because I couldn't really see anything loose that could be tightened or tied down. The steel wool works very well, but as expected it rusted away. Aluminum foil is my next approach. That noise comes from the bottom of the car, this other one seems to come from a different place.

I haven't done anything to the car recently, other than replace the rear brake pads last month. No CELs, no other indications of any kind. Gas mileage is as expected.

I'm reasonably certain it's not coming from the speakers. My ears are good at that sort of thing, but.... Would a radio noise equally come from both channels on AM? My cell phone chirps through the radio, and that noise is 'in the middle of the car,' From the driver's seat the noise seems to come from the front-right side of the engine compartment...which wouldn't be true mono. I have been fooled in the past...in another car a loose hood spacer near the grill made the hinge rattle, and drove me nuts for a couple years before I finally figured it out. I have not ever replaced the plug wires, but I got the car, a '99, four years ago. They could be old and leaky.

Thanks for the questions, guys.

-John O

Hey there John, Check the CV joints and bearings. I have the same symptoms and I have identified the source. Both CVs are needed. I have got a 1986 Sub GL

Yet another source of whine could be the front differential - if your high-pitched sound is like a very faint jet engine (best sound I know to describe it!) coming through the firewall. It will continue to get louder the longer you drive the car. Might check the gear oil in your front differential, make sure it is within reasonable specs. Probably won't produce vibration at the start of failure, but will toward the end. Some tranny shops are willing to do free diagnosis of transmission troubles, and may be able to spot if this is the case, but I would still opt for a trusted second opinion if they say so as the repair is nightmarishly expensive.

Good that there are no malfunctions for the check engine light to report.

How about the Power light? I forgot to mention that one. The "Power" indicator lamp on your dash that lights when you do a throttle step-down may flash when the car is started to indicate a stored code for the transmission, or may remain illuminated for a peculiarly long period of time. A few months after my differential began to fail, and after I had it diagnosed, I began receiving the trouble code for front differential from my transmission nearly every time I started the car. Better late than never? :-P

I think you are probably right about the sound being monaural on the speakers if the plug wires are throwing out noise, but due to obstructions, you may not be able to perceive it as such. Should be able to rev the motor while parked and listen to each speaker, observing obvious precautions of course. (-;

~Brian

Power light...I've never seen that light before. Either I don't have one or it's burned out like the low fuel light. ;-)

Differential, or maybe CVs, huh? OK. Does that still match up to the fact that the noise seems to be "attached" to me pressing the gas or letting up slightly at 75 mph? The torque causes the noise, maybe?

If so, how do I check the front diff fluid, or replace it? I read something about those fluids here a long time ago, but the actual details were sketchy. Maybe a tranny shop can do it for $40??? Is it that kind of a job? CV's is going to $uck.

I'm considering selling this car in the fall...too much of this stuff happening. I need struts all around, the tranny is just weird, and the timing belt is past due for replacement. I can't afford all this. I love the car, especially with our snow-belt winters, but it's too expensive for my budget when I also include the low daily gas mileage. :-(

-John O

Power light is on the Auto trans, can't say for the Manual trans. Carl, don't you drive a manual, or anybody else reading this thread with a manual? Do they still have the power light on the dash for the manual? Last Subie manual I drove was an '89 Justy, and no, I can't recall a power light anywhere on that one.

Differential, I would say yes, CVs, not really familiar with them whining, just clunking, and mostly in turns and while under load (accelerating) unless neglected for an extended period.

On the auto tranny, there is a dip-stick for the differential on the passenger side (American) of the transmission. Unlike the transmission dip-stick, the differential dip-stick unscrews, so don't bust your fingers trying to just pull it out.

On the manual, again my apologies, but I really can't speak to something for which I am ignorant, without speculation. Anybody know if the differential and manual tranny share a common gear oil, or if there is a seperate check for the front differential? I suppose this would be in the owner's manual somewhere. I will try finding it later.

Never changed diff. fluid before myself. But the procedure should be simple enough. Drain old, and refill through dip-stick hole. I can only speculate that it would be best to drive a little, to raise the oil temperature some and resuspend as many particulates as possible.

~Brian

Thanks, Brian. This is an auto trans. I'll have a peek at the diff fluid this weekend. Sounds easy enough to replace, and at 140k miles, what the heck.

-John

Check the front license plate. If it's loose in any way, it'll sound like what you discribe.

Good idea. Some folks have had ABS pumps buzz. Can't see how it would manifest itself as you describe though. And of course you may not have ABS on the car!

Carl

I do have ABS, but no front plate or bracket. That's similar to the hood thing I mentioned, I'll definitely have a good peek under there this weekend, shaking everything that could be loose.

-John