DISCO3.CO.UK - View topic - Strange resonating engine noise..

lard

Member Since: 07 Jul 2018
Location: Wiltshire
Posts: 143

2008 Discovery 3 TDV6 SE Auto Tonga Green

Strange resonating engine noise..

Hi folks

Am starting to investigate a high pitched resonating noise that fades in and out when idling - so far I’ve just narrowed down the area it’s coming from and turned off aircon to see if it made a difference

I think it’s something attached to the belt but not sure which component....

Made a video - anyone have suggestions as to where to start? It’s different to the lower belt tensioner noise (new one about 5k miles ago):

Any pointers appreciated

Thanks

8th Nov 2020 3:15 pm

Kilovolt

Member Since: 29 Jun 2015
Location: South Derbyshire
Posts: 1020

2013 Discovery 4 3.0 SDV6 Commercial XS Auto Baltic Blue

Good afternoon,

Might I suggest, with two rollers and a tensioner on the timing belt and two tensioners associated with the auxiliary belt, I would say start by investigating them (notwithstanding the upheaval to get to the timing belt).

https://www.advancedfactors.co.uk/camshaft-drive-belt-156-c.asp

https://www.advancedfactors.co.uk/auxiliary-drive-1601-c.asp

The rollers should spin with a little resistance and not freely without stopping quickly.

https://www.youtube.com/watch?v=DLDdAx9x9dI

I guess an even quicker check would be to remove the cooling fan and run the engine again.

Please bear in mind I am a sparky and not a clanky although I have some very nice race engines I work on and look after

Good luck

"Track day running - Don't put your foot back on the accelerator until your absolutely sure you don't have to take it off again"

Current Ride: D4 XS Commercial Baltic Blue SDV6 fully loaded with heated everything

Track Days: BMW E36 M3 Evolution MY 1996 (3.2 Litre 377 BHP sat in 1,250 Kgs of car, with a pro safety cage and some serious braking power)

8th Nov 2020 3:41 pm

lard

Member Since: 07 Jul 2018
Location: Wiltshire
Posts: 143

thanks for the suggestion - I've had the fan and cowling out and removed the aux belt - everything spins freely, though a wiggle test shows that the water pump pulley can be moved up and down on it's axis by a couple of mm - certainly doesn't feel as secure as I'd assume it should be,

Run without the fan and the noise is defo still there, coming from the passenger side at the front which is bang-on where the water pump is, so fingers cross, got one on order from JGS (along with the idler, as didn't change when I did the tensioner and belt last time!)

9th Nov 2020 2:25 pm

Globetrotter448

Member Since: 21 Mar 2017
Location: Londonderry NSW
Posts: 1783

2007 Discovery 3 4.0 V6 Petrol SE Auto Java Black

If there is play in the water pump, and it should not have any, then that is more than likely the candidate. It would be a good move to change the idlers as well.

10th Nov 2020 9:09 am

Kilovolt

Member Since: 29 Jun 2015
Location: South Derbyshire
Posts: 1020

Just from my own experience (again please note electrical skillset

), be careful and take your time fitting the water pump.

I must have been 'too rough' when re-inserting it and I crimped the o-ring. Needless to say it leaked on refilling the system so I had to start again. It was right the second time.

Secondly, be careful loosening and tightening bolts on the water pump. You will be working from above and it is very easy to get your socket set onto the adjacent fixings (not associated with the water pump). I'm sure I read this as a warning on here before making my swap. But in any case, use a mirror or plenty of touchy-feely (technical term) and take your time.

Just my thoughts

"Track day running - Don't put your foot back on the accelerator until your absolutely sure you don't have to take it off again"

Current Ride: D4 XS Commercial Baltic Blue SDV6 fully loaded with heated everything

Track Days: BMW E36 M3 Evolution MY 1996 (3.2 Litre 377 BHP sat in 1,250 Kgs of car, with a pro safety cage and some serious braking power)

10th Nov 2020 9:34 am

lard

Member Since: 07 Jul 2018
Location: Wiltshire
Posts: 143

noting the electrical background! I did my apprenticeship in electrical engineering.... the attitude it's given me is that, if I've mastered something invisible that can kill you...how hard can anything else be?

This'll explain why I have no heating after 7 years in the house...

Noted on the bolts, hoping the waterpump ships from JGS today!

10th Nov 2020 10:00 am

lard

Member Since: 07 Jul 2018
Location: Wiltshire
Posts: 143

Removed the idler, noted it was a genuine landrover part, then put the bearmach one in and it doesn't spin true

- put original back

Next removed the old water pump... looked like the original one it came with - spun it and you can feel the lumpy bearings and notchyness!

put the new one in, refilled the coolant and sounds much quieter - thanks all for the pointers!

There's a benefit to continual maintenance - I've had the cooling fan off at least half a dozen times in the last 12 months so everything went off and back on easily enough

13th Nov 2020 2:20 am

Kilovolt

Member Since: 29 Jun 2015
Location: South Derbyshire
Posts: 1020

"Track day running - Don't put your foot back on the accelerator until your absolutely sure you don't have to take it off again"

Current Ride: D4 XS Commercial Baltic Blue SDV6 fully loaded with heated everything

Track Days: BMW E36 M3 Evolution MY 1996 (3.2 Litre 377 BHP sat in 1,250 Kgs of car, with a pro safety cage and some serious braking power)

13th Nov 2020 8:06 am