Should I be worried? (video)
 

After the car has been stored I've started hearing some noise from the alternator or maybe the water pump. It goes away after a minute but appears again if the car has been standing still for a couple of weeks. The airbag warning lamp disappeared after I started it again a second time..

Should I be worried?

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Harmonic balancer slipping ? common on the X300

Paint the dots on the 2 halves and see if they stay aligned after shut down

If bad this will keep the belt from turning the engine coolant pump

https://www.jaguarforums.com/forum/x...lancer-101674/ :icon_dance-disco:

There is the AC belt pulley on the on the right side

There is some tricks to removing it as the long bolt rust up

There is a cheap Gates brand replacement

https://www.jaguarclassicparts.com/u...-3-2-4-0-litre

Belts and wheel are new. just changed them a few months ago

Since the noise dissipates a bit after a few minutes my money is on the alternator.

Cheers
DD

I'm guessing that the noise will disappear when spring comes and I'll start using it on a daily basis again. But is the noise a sign of a failing alternator? Should I plan already for a replacement?

Sometimes sounds don't come out right in videos. But, judging from the amount and intensity of the sound, I'd be worried about the alternator, yes.

When under a heavy load (after engine start, for example) a bit of additional noise might be expected from the alternator. A slight whine.

What I'm hearing sounds significant, though.

Cheers
DD

Hi Tcasmarcus,

An inexpensive mechanic's stethoscope, available at most auto parts stores, Harbor Freight, Northern Tools, etc., can help you locate the source of your noise without removing the belt. While avoiding moving belts, pulleys and fans, carefully touch the probe to the alternator body, water pump, air injection pump, A/C compressor belt idler pulley, etc.

Cheers,

Don

Takes five minutes to pull the belt. Feel the bearings in the alternator, feel the bearings in the WP. Start the car briefly and confirm the noise is not present.

My money is that you will feel bad bearings in the alternator and when it is working hard they make noise.

update. spring is coming so i took the car out of storage. started it. no sound.. so i started driving.

after a few minutes it came back though. almost like a turbo whine as it followed the rpm of the engine. 20 seconds later it was gone. came back again after 5 minutes but only lasted 20 seconds again. drove the car for a few hours and havent heard anything of this sound again since.. now i have used it daily for a week and the sound has disappeared completely.

i did notice that the alternator belt was not very tight so i tightened it. only problem now though is that once in a while the airbag light goes on. if i stop and start again it always disappears.

will also tighten the ac belt as it felt lose, but not sure if that could in some way be connected to airbag issue..?

It is unlikely that the airbag warning is related to the noise unless the alternator output voltage is low. Low system voltage can trigger all manner of spurious trouble codes and warning lamps. If you have a voltmeter you can test the voltage across the battery terminals with the engine off, which should be around 12.6V or better, then again with the engine running, which should typically be about 1V or more higher than static battery voltage.

Cheers,

Don

A trick to hear bad bearings in pumps or alternators is to use a long screwdriver what we call Stanly screwdrivers its got a square shaft big yellow handle some have the shaft steel go right up to your palm
then place the end on the housing near the pully put your ear to it and you will hear it grinding away.
maybe a socket extension would do.

again, thanks a lot guys for valuable assistance as usual . have not followed up this topic further because my car now repairs it self, apparently.. no more sound and no more airbag warning since i started using it again on a daily basis.. 😄

Last Winter,(has it gone?) I had a squeal from my engine on start up. It stopped after a few miles. I had some work done on my engine, changing drive belts, and it was reported that the water pump was very stiff to turn by hand, also the air con pulley. So I had them changed - noises all gone. The water pump is very notchy and stiff and there is a nice groove worn into the plastics outer pulley face of the other pulley. The belt had clearly been slipping.