Thoughts on this worrying sound

Rilot · 25 Jul 2017 at 09:11

So, the Jaaaaaaaag has started making a worrying sound.

Engine bay

From outside with hood shut

To me, that sounds like main-bearings or may be big end. What do you think? Maybe water pump?
I would be very surprised if it was bearing failure though as the motor only has 30k on it.

Gibbo · 25 Jul 2017 at 09:14

If you very gently rev it does the clanking noise go away? If it does could be big end on its way out. If it goes faster, then probably too late, but it could also be a dry bearing too as it sounds pretty rough but it is a dag dag.

Firestar_3x · 25 Jul 2017 at 09:16

Could be anything from the snout nose bearing on the supercharger to any of the accessory tensions / bearings.

How does it sound when you rev the engine?

paradigm · 25 Jul 2017 at 09:21

Could also be something as benign as a centrifugal clutch failure, is the A/C working?

Rilot · 25 Jul 2017 at 09:25

Gibbo said:
pretty rough but it is a dag dag.

How dare you! It's a 5.0 V8 petrol.

paradigm said:
Could also be something as benign as a centrifugal clutch failure, is the A/C working?

AC works fine. It has an electric fan so no centrifugal clutch.

Firestar_3x said:
Could be anything from the snout nose bearing on the supercharger to any of the accessory tensions / bearings.

How does it sound when you rev the engine?

Non SC so not that. If I rev the engine it just makes the same noise but faster.

paradigm · 25 Jul 2017 at 09:33

Rilot said:
AC works fine. It has an electric fan so no centrifugal clutch.

Correct me if I'm wrong, but the type of fan is irrelevant, I'm talking how the A/C compressor is engaged. That said, if the A/C is working OK this is unlikely.

vanpeebles · 25 Jul 2017 at 09:34

Have you tried the old ear on a long screwdriver handle trick? Might help locate the sound a bit better.

Howard · 25 Jul 2017 at 09:38

To me, that sounds more like a bearing on some sort of accessory drive (alternator, air con, etc) - it seems less rhythmic than something internal like big end/main bearings.

Firestar_3x · 25 Jul 2017 at 09:38

vanpeebles said:
Have you tried the old ear on a long screwdriver handle trick? Might help locate the sound a bit better.

This will be worth a try and go round all the accessory bearing locations.

Nomisf · 25 Jul 2017 at 09:48

To my ear thats a failing water pump, hollow aluminium-y sound at acessory speed.

Water pump bearing seems to be a common failure on the 5.0, but beware if goes - your drive belt will be thrown off and you will loose any function driven by it!
(On my MG that was Alternator, PAS, AC and Aux Vaccum Pump, was interesting!)

Rilot · 25 Jul 2017 at 09:50

Howard said:
To me, that sounds more like a bearing on some sort of accessory drive (alternator, air con, etc) - it seems less rhythmic than something internal like big end/main bearings.

That leads me to think it's the water-pump. It's on the top of the engine at the front.
I'll try the AC on and off to see if that affects the sound. If it the compressor bearings then I would expect the sound to change once load is on the compressor.

Will go round withe a screwdriver later on today once I've fixed the water leak from my tank in the house.... it never rains but it pours......

vanpeebles · 25 Jul 2017 at 09:56

Rilot said:
Will go round withe a screwdriver later on today once I've fixed the water leak from my tank in the house.... it never rains but it pours......

Not literally I hope

snapdragon69 · 25 Jul 2017 at 10:17

paradigm said:
Correct me if I'm wrong, but the type of fan is irrelevant, I'm talking how the A/C compressor is engaged. That said, if the A/C is working OK this is unlikely.

It will be a variable displacement compressor (permanently engaged) on any decent car from this decade, not a clutch.

Dis86 · 25 Jul 2017 at 10:18

I was gonna to offer my sage advice and wisdom then noticed you used the word hood.

HOOD.

Pft.

Nah sounds fairly similar to a knackered water pump on the gfs mini recently!

slick rick · 25 Jul 2017 at 10:25

Can you remove the drive belt and run the car briefly to see if the noise persists?

Rilot · 25 Jul 2017 at 11:26

Yeah, I could. Need to take half the front end off to access it though. I'll maybe have a look at doing this tonight as it's a good shout.

Dis86 · 25 Jul 2017 at 12:02

Rilot said:
Yeah, I could. Need to take half the front end off to access it though. I'll maybe have a look at doing this tonight as it's a good shout.

Before you run it spin any pulleys or bearings you can get your mitts on just to check them.

Rilot · 28 Jul 2017 at 14:17

Happy to report that the sound was the water pump. Booked it in for a new one.

Phew!

paradigm · 28 Jul 2017 at 14:20

Always nice to find that a problem is only mildly costly rather than ruinously expensive!

Rilot · 28 Jul 2017 at 14:24

Yeah, £200 + VAT for the part. If it was the timing gear or main-bearings I'd be looking at £5k to £10k for a full strip and rebuild at which point I would have just parted it out probably.