Xc70 D5 cant diagnose strange noise? Video linked

[OWF]

Hi there,

I have been trying to diagnose this strange noise which is present occasionally (becoming more regular) on a cold start. It's a sort of gurgling sound.

It’s hard to predict when it will happen, but seems if sat for a few days or when particularly cold the noise will be more likely to be present but that could be a coincidence.

The noise starts briefly after the engine starts and lasts for a few seconds for now.


I have tested by taking the belt aux belt off but no noise, put the belt back on and again no noise. Maybe I have just been unlucky when testing.

So far I have replaced the alternator pulley as that seemed the most common fix, power steering pump and aux tensioner belt pulley.

Heres a short video, noise heard at 11 seconds:

https://youtu.be/uvzJHkSphVk

Any help or suggestions would be appreciated.

Thanks.

[Simmy]

alternator bearings make this kind of noise also check ac pump bearings.

[OWF]

Thanks for the reply. I have changed the clutch pulley, are there any other bearings in the alternator?

I will look into changing the AC pump bearing, but I haven't found any other examples online of the Ac bearing being at fault. With the belt off the Ac pulley spins well with no noises.

[myfirstv70]

Originally Posted by OWF

Thanks for the reply. I have changed the clutch pulley, are there any other bearings in the alternator?

I will look into changing the AC pump bearing, but I haven't found any other examples online of the Ac bearing being at fault. With the belt off the Ac pulley spins well with no noises.

As well as the alternator pulley/ clutch you have a bearing at each end of the alternator shaft - these can go bad.

I've said this before and I'll say it again: the easiest way to isolate a noise in a cacophony of noises is to get a longish solid bar preferable metal and put one end on the, say, alternator while putting your ear on the other end-block your other ear with your hand. You'll be amazed how many different sounds you hear....you'll be like a sonar operator! I did this to diagnose my alternator pulley was knackered....give it a go!
HTH,
Nobby