S80: Engine Grinding/groaning noise at low speed, 07 S80 V8

[SpooForBrains]

Hi, I've prefixed this as engine but it could equally be gearbox or something else, so apologies.

I bought a 2007 S80 v8 from a seller about 480 miles away that on inspection seemed to be in excellent condition. It was delivered to me yesterday.

My first drive went without incident. Parked it up for about 30 minutes and then drove 15 miles to the cinema. On that drive a noise started coming from the engine bay at low speed (from moving off, most noticeable at about 30-40 miles an hour). The car seems to drive normally and the gearbox appears to shift as it should, although I'm not familiar with what's normal for this car. The noise seems to go away at higher speeds but that could just be because the noise of the engine drowns it out. I parked the car for about two and a half hours and then on the drive home the noise was present from starting the car all the way home during the low speed portions of the journey.

The best description I can make is that it sounds like the noise you get from the gearbox when you reverse a car, except more buzzy. It's also accompanied by a metallic ringing that sounds a little like a load of ball bearings being swished round in a can.

The noise was NOT there on the first drive of the car, and I didn't do anything at all reckless or unusual during that drive. I allowed the engine time to warm up and drove at a sensible speed and at a sensible pace for about 20 miles.

You can hear it in this video (I was driving, my passenger was filming). I am travelling at low speed in this video. It sounds quiet on the video but it's very noticeable in the car and appears to come from the engine bay, and is not more noticeable with the window open (meaning it's coming through the car, if that makes any sense at all). You'll probably need headphones to hear it. The squeaky rear suspension you can hear I already knew about when buying the car.

https://www.youtube.com/watch?v=y0ow...ature=youtu.be

I'd REALLY appreciate any input as to what the problem may be and how to further diagnose it.

Edit: Another video where the drone is audible
https://www.youtube.com/watch?v=zLiY...ature=youtu.be

And a video of the noise under the bonnet at idle
https://www.youtube.com/watch?v=sEYH...ature=youtu.be

[Tannaton]

I'm not familiar with the S80 but it's the same drivetrain as the XC90 (incl. V8) which I am familiar with...

- That sounds like metal on metal at low speeds so I don't think it would be the engine.

- Get underneath and check if the transfer box output flange is catching on the steering rack heat shield. I have seen this happen if the engine mounts have sagged on diesel models, I'm not sure if the V8 it laid out in the same way but as it uses the same gearbox it is likely to be.

- Check also the propshaft support bearings - I think there are two on the P3 based S80 AWD & XC70. They can go dry and start to squeak and then they grind...

From a brief watch of your videos it does seem as though you are more likely to get the noise when the drive train is under torque - i.e. setting off.

[Thommykent]

How many miles on the vehicle? I can`t really identify the sound you hear, but my 07 V8 does not make a sound as you describe.

[harveys]

Could be worth listening to the alternator bearings or one way clutch on the belt drive.
The alternator gets very hot as its very close to the exhaust pipework..

[SpooForBrains]

Noise goes on and off with the aircon (I discovered while waiting for the mechanic, also explains why I didn't hear it on the first run I had, it was cold that day, left the aircon off).

Mechanic reckons it's the aircon compressor clutch. Compressor will need replacing. I can live with that.

[Fernando]

I own an S80 V8 also, with 92.000 km, mine has the same noise at low speed , I would say between 20 to 30 km/hr (like tipically gear reduction) and it increase with the Ac on. Did you solve the problem finally

[Kev0607]

Originally Posted by SpooForBrains

Noise goes on and off with the aircon (I discovered while waiting for the mechanic, also explains why I didn't hear it on the first run I had, it was cold that day, left the aircon off).

Mechanic reckons it's the aircon compressor clutch. Compressor will need replacing. I can live with that.

My Dad's V70 is making the exact same noise when the air con is on only, but no noise when its off.

How much is a compressor going to cost?

[bugeye]

Make sure the refrigerant charge is correct. The only way to be correct is to evacuate the AC system then charge with the correct weight of refrigerant. This is not a do it yourself project. My AC made the same noise. Had the refrigerant recharged and all is good. Don't spent on a new compressor until refrigerant is correctly charged.

[Kev0607]

Thanks for the advice. How much is a new compressor though?