'01 S60: "scratching" noise under dashboard, then LOUD bang

Post by **paul1149** » 23 Jan 2025, 15:26

I have an '01 S60 base model. Everything's been running well. It sat for almost a week during some very cold weather.

Today I warmed it up and then headed out to the highway. I was out about 8 minutes when I began to hear a noise apparently from under the passenger side dashboard. it sounded like a large mouse scratching, but it seemed too regular to be from an animal. (Later on, it also stopped when I parked and turned the engine off, so I discount it being an animal, but who knows?)

So as I was driving, wondering what this noise was, suddenly there was a huge BANG. It startled me, and I thought for sure something had hit and cracked my windshield, but there was no damage. I was following a semi box trailer, but there was no extraordinary reason for something to come off of it.

After I did my shopping and was out on the highway again, after a few minutes the under-dash noise picked up again. I was spooked and kept it to 60-65mph (speed limit was 65). When I got home I popped the hood with the motor running, and nothing looked awry.

I wish I could describe this better, but I'm trying to figure out what is going on. No dash lights came on. This never happened before.

Post by **scot850** » 23 Jan 2025, 16:18

Maybe they are unrelated? The scratching noise could be the fan motor bearings getting noisy, or possibly one of the actuators for the flow direction stuck?

Do you have a moon roof? Have you checked that has not cracked?

Neil.

Post by **paul1149** » 23 Jan 2025, 16:24

Thanks. I should have mentioned that I do have a sticking actuator. It's constantly trying to move but apparently never gets there. Turning off the heater fan and moving the air flow direction knob didn't affect anything. But the boom was loud - it had to be more than the fan or duct work can account for.

I have a moonroof, and it is not shattered. I need to check it more closely for cracking, which I will do tomorrow.

Post by **BlackBart** » 23 Jan 2025, 16:49

Good call that they might be separate noise sources. Could it have been a rock or something that hit the underside and bounced away, no damage? You might heck the CV joints on the side you heard the noise from, but if it shattered, there would be ongoing noises afterwards.

Post by **paul1149** » 23 Jan 2025, 16:54

They could be entirely separate, but it's very odd that after 145k miles this would be the first time for the scratching, followed in a minute by the loud boom.

I don't think the noise came from under the car. I did redo the axles a few years ago, and I never was happy with the fit or performance of the one on the driver's side (there sometimes is a subtle vibration).But I can't make the connection to this problem.

Post by **BlackBart** » 23 Jan 2025, 17:18

A rock stuck in the brake shield?...scratch scratch scratch every rotation....then it spit it out against something? Just thinking out loud here. Did you feel the bang, like it had some weight to it? Did you feel it in the steering?

Post by **Blacklab467** » 23 Jan 2025, 17:24

Is it AWD? I'm thinking the angle gear input my have been failing and finally lost it's union with the collar sleeve. If so, go find some slippery road or wet grass and see if it still works.

Post by **paul1149** » 23 Jan 2025, 17:28

It didn't seem to have a cyclical nature to it, it seemed more random. I am going to take it out again tomorrow and try to learn more. I'm not familiar with brake shield. But I would think if it was a rock that then was ejected, the noise would stop. And that scenario wouldn't, I think, approach the volume of the bang I heard. I need to examine the front exterior of the car, too, to see if something hit a fender or grill.

No, it's FWD only.

Post by **paul1149** » 24 Jan 2025, 09:24

Been searching around, and am beginning to suspect the automatic tranny. 145k miles, have been having occasional minor slippage going into 3rd gear. That could explain the background "scratching" and somehow the loud boom, which would be ominous. Fluid has never been changed, and is filthy. No error code appeared.

Post by **jonesg** » 24 Jan 2025, 16:47

paul1149 wrote: ↑24 Jan 2025, 09:24 Been searching around, and am beginning to suspect the automatic tranny. 145k miles, have been having occasional minor slippage going into 3rd gear. That could explain the background "scratching" and somehow the loud boom, which would be ominous. Fluid has never been changed, and is filthy. No error code appeared.

Tough time of the year but theres no substitute for getting under the car...or paying a shop to lift it and give it a once over.
Scratching on my car was the dust shield on the brake, its a flimsy backplate, I bent it with my hands so it no longer touched the brake disk.

Could also be a lazy bendix on the starter, it can stick and rub the flywheel.

Next time it makes noise , shift into neutral, see if it goes away.
Apply brakes, see if it changes.
Check the center caps on the wheels, the axle bolt went awol on mine and the drive shaft started migrating.
Inspect the serp belt.
Sneak a peek in the timing belt cover.