Hi Guys,

HOPEFULLY RESOLVED!

Replaced the tensioner and idler pulley today and the vibration and rattle has gone. I’ll probably replace the alternator pulley in the near future in case it may have been the main issue, but for now it’s sounding a lot better.


Over the past few months my 2014 SD4, 94000 miles has developed a quite worrying vibration/thumping./banging at low tick over. It is particularly loud when coming to a stop whilst still in drive but quietens when in neutral and disappears when driving.
I am hoping the video is clear but without 3 D sound it can be hard to pin point.

Initially I thought it was something loose and intended to investigate but when I checked everything in the engine bay all was solid. With the aid of my son we were able to establish it was coming from the area close to cylinder 1 on the left as you look from the front end but really am not sure what or how is the cause.
A mechanic at my local more trusted indie wasn't sure either but ruled out timing belt or pump as it wasn't coming from that area. Another Land Rover mechanic said it sounded as though it involved the area where cams and springs are located but didn't seem too concerned as it was costly to repair but wouldn't be high on the agenda as it wasn't an issue as cost to fix would be quite high.

We're heading off in a few days time to the Lake District towing a caravan and have to admit it is concerning but if anyone could shed some insight of thoughts to give me peace of mind it would be appreciated. But its a case of carry on regardless or sit tight and cancel our holidays until after a further inspection can be carried out... in November...

It appears I have forgotten how to upload pictures to the thread...

Last edited by O-B-Wan003 on 25th Sep 2024 4:58 pm. Edited 2 times in total

https://youtube.com/shorts/dgRl9F8HnU0?si=hGnHi07s8LW-4AZW

OK have seen the video now. Sounds like exhaust blowing. But I cant orientate myself with the video - is that back or the front of the engine?. A zoom out and zoom in would help.

I'd take the engine cover off and repeat the inspection. Loose injector can make an awful sound too. Jules

Jules, was kinda thinking it was injector related but not confident with a self diagnosis
The engine cover has been removed so what your looking at is the rubber cover on top of the injectors but if you're looking at it from the from offside headlight if you get me. Just a quick photo sorry pointing to the area but without the engine cover removed.

The EGR unit is just below that area, and turbo below that, and I wonder if there is an exhaust leak.

Without a close inspection is difficult to be more precise.

Id take the cover off again and the rubber insulator and have a good listen and feel around. Jules

Last edited by jules on 3rd Sep 2024 8:25 am. Edited 1 time in total

Thanks Jules, I'll have a go at it tomorrow when the weather improves. Don't recall any exhaust fumes or sign there was a blow out but will check and see if there's anything loose and possibly a better video. Also the possibility of a loose or outgoing injector.

Perhaps Im not hearing what you are.
Locating the source of sounds can be frustrating Im afraid.

Earlier this year I was fairly sure my rear diff was whining - but it was the tyres. Jules

Is this the idler pulley or tensioner? This appears to be the cause of the rattle/judder at low revs.

I'm now wondering if this could fail at any stage as we will be towing the caravan a few hundred miles dow to the Lake District on Thursday..

https://youtube.com/shorts/0JUZq-SWTE0?feature=share

I had to replace one of my idler pullies about three years ago, fine up to a few weeks ago when I changed my belts and the gubbins

O-B-Wan003 wrote:

Is this the idler pulley or tensioner? This appears to be the cause of the rattle/judder at low revs.

I'm now wondering if this could fail at any stage as we will be towing the caravan a few hundred miles dow to the Lake District on Thursday..

Thanks Bluebird, very much appreciated for the link. Looks like I’ll be busy on our return from holiday. Just hope it gets us there and back again 😂

That slapping of the belt on the tensioner pulley is very characteristic of a worn overun alternator pulley (OAP) - it works like a freehub on a bicycle - allowing the alternator to continue to spin fast when the engine slows down. When the OAP fails it drags the alternator down and puts a lot of extra tension in the belt causing the tensioner pulley to jump about . The OAP is easy to test with the AUX belt off.
You need a special tool (not expensive) to remove it from the alternator though - to hold the alternator shaft and turn the OAP separately.

M10/33teeth tool



The idler and tensioner pulleys are easy to replace (ive just done mine). Jules

Last edited by jules on 4th Sep 2024 7:26 pm. Edited 1 time in total

Jules, very much appreciated!
When I did a search on the web Scott and Alana popped up with a video on the exact same thing. Doesn’t appear to be overly difficult just a few points where attention needs to be paid.
I’ll order the parts and hopefully get it sorted on return from our hols.