Belts, noises, unsettled

Howie666 · 26th January 2022, 20:58

Hello everybody,

I'm still going, and so is the Raptor (just!) We had a fright when she failed the mot, that's behind us now but there's a perplexing fault I haven't been able to identify properly yet.

We had the belts changed and a refurbished alternator fitted, but when she came home she had developed a rubbing/whooshing noise at idle. I suspected the alternator belt was/is binding. Additionally there is a rattle when accelerating through the gears - second gear, accelerate to change up speed, rattle, third gear, accelerate to change up speed, rattle etc. The voltage also fluctuates and at traffic lights the bulb warning comes on until I rev the engine again.

I have concluded that the belt tensioner is loose/blown bearings (the rattle) and that the loose belt is causing the voltage fluctuations.

I would very much appreciate your wisdom as to whether or not I am on the right track!

All advice gratefully received, as always.

Dale

trikey · 26th January 2022, 21:41

Sounds like an over tensioned belt to me.

Howie666 · 27th January 2022, 02:42

Quote:

Originally Posted by trikey

Sounds like an over tensioned belt to me.

Thank you Andy. Please could you let me know what I need to do to fix it/ask the garage to do?
Dale

SD1too · 27th January 2022, 08:46

Hello Dale,

Since the ancillary belt tensioner on the KV6 is self-adjusting, it would be a bit of a coincidence for it to fail at the same time as the repair work was done on your car.

Quote:

Originally Posted by Howie666

We had ... a refurbished alternator fitted ...

The symptoms you've described suggest to me that the replacement alternator was poorly refurbished or not at all. The next step is to discuss this with whoever fitted the alternator.

Simon

trikey · 27th January 2022, 09:25

Drop the aux belt off, and start the car see if the noise disappears, if it does you know it’s aux related, if not check the tension of your main belt.

Howie666 · 27th January 2022, 13:04

Hi Simon,

I was initially thinking that the alternator was faulty but I have had it checked by an auto electrician and its working ok. The belt noise I'm describing comes from the offside of the engine, which is what I guessed was the serpentine auxiliary belt that loops around the aircon compressor.

I think I might be wrong about which belt it is. I'm still pretty lost but my autism keeps nagging me to get it fixed because I am paranoid about something disastrous happening if I don't

SD1too · 27th January 2022, 14:58

Quote:

Originally Posted by Howie666

I was initially thinking that the alternator was faulty but I have had it checked by an auto electrician and its working ok.

So what about this then? ....

Quote:

Originally Posted by Howie666

The voltage also fluctuates and at traffic lights the bulb warning comes on until I rev the engine again.

How exactly does the voltage fluctuate? Once the warning light is extinguished, does the voltage remain stable as you increase the engine speed?

Quote:

Originally Posted by Howie666

I think I might be wrong about which belt it is.

The other possibility is indeed the front timing belt tensioner in which case you must ask whoever did the belt change whether they (1) used the service tools and (2) set-up the tensioner & pulley according to the INA instructions. I'd advise that you don't use the car until you know because if the tensioner isn't working correctly there's a real risk that the belt will be damaged. The rubbing/whooshing noise is worrying.

Simon

Howie666 · 27th January 2022, 16:53

Well, when she is traveling under normal circumstances, the voltage stays at around 14. When I stop at traffic lights, it drops as low as 12 sometimes, but increases if I rev the engine.

Rich in Vancouver · 27th January 2022, 18:39

Sounds like a too-tight timing belt to me as well.
The tensioner installation is not straightforward and if the installation instructions aren't followed it can cause issues, either the tensioner roller making contact on the mount or the belt being too tight, resulting in a noise like the one you describe. (Don't ask me how I know!

)

Here is a pic of a tensioner in a vise. It is adjusted by rotating it in the direction of the arrow. If you aren't careful the tensioner will slip over centre and the roller will contact the bracket on the lower left. If this happens you can still adjust it so it's no longer in contact but the belt will be too tight. The hole for the hex key must be on the lower right side as shown. If it's not, the tensioner is over center and the tension won't be correct.

And here are the instructions that come with the new tensioner. Unfortunately these are often left in the box by technicians.

SD1too · 27th January 2022, 19:37

Quote:

Originally Posted by Howie666

Well, when she is travelling under normal circumstances, the voltage stays at around 14. When I stop at traffic lights, it drops as low as 12 sometimes, but increases if I rev the engine.

Thanks Dale. That indicates a regulator fault. I don't know how your so-called auto electrician could have missed that.

I'd get the alternator sorted before you start worrying about timing belts.

Simon

26th January 2022, 20:58	#1
Howie666 I really should get out more....... MG ZT 190+, Trophy Blue Join Date: Nov 2009 Location: Preston Posts: 2,067 Thanks: 1,401 Thanked 309 Times in 195 Posts	Belts, noises, unsettled Hello everybody, I'm still going, and so is the Raptor (just!) We had a fright when she failed the mot, that's behind us now but there's a perplexing fault I haven't been able to identify properly yet. We had the belts changed and a refurbished alternator fitted, but when she came home she had developed a rubbing/whooshing noise at idle. I suspected the alternator belt was/is binding. Additionally there is a rattle when accelerating through the gears - second gear, accelerate to change up speed, rattle, third gear, accelerate to change up speed, rattle etc. The voltage also fluctuates and at traffic lights the bulb warning comes on until I rev the engine again. I have concluded that the belt tensioner is loose/blown bearings (the rattle) and that the loose belt is causing the voltage fluctuations. I would very much appreciate your wisdom as to whether or not I am on the right track! All advice gratefully received, as always. Dale __________________ Commission Number 352 To do list: 1. Reversing sensors 1a. Headlights polished - DONE! (Magic Mike ) 2. Auto dip rear view mirror 3. Seats replaced - DONE! (thank you Mischief) 7. Bodywork repainted 8. Inlet manifold changed for a working one - DONE! (Magic Mike )

26th January 2022, 21:41	#2
trikey Premium Trader Rover 75 Join Date: Nov 2010 Location: Devon Posts: 33,772 Thanks: 8,837 Thanked 14,831 Times in 8,030 Posts	Sounds like an over tensioned belt to me. __________________ Lest we forget..

27th January 2022, 09:25	#5
trikey Premium Trader Rover 75 Join Date: Nov 2010 Location: Devon Posts: 33,772 Thanks: 8,837 Thanked 14,831 Times in 8,030 Posts	Belts, noises, unsettled Drop the aux belt off, and start the car see if the noise disappears, if it does you know it’s aux related, if not check the tension of your main belt. __________________ Lest we forget..

27th January 2022, 13:04	#6
Howie666 I really should get out more....... MG ZT 190+, Trophy Blue Join Date: Nov 2009 Location: Preston Posts: 2,067 Thanks: 1,401 Thanked 309 Times in 195 Posts	Hi Simon, I was initially thinking that the alternator was faulty but I have had it checked by an auto electrician and its working ok. The belt noise I'm describing comes from the offside of the engine, which is what I guessed was the serpentine auxiliary belt that loops around the aircon compressor. I think I might be wrong about which belt it is. I'm still pretty lost but my autism keeps nagging me to get it fixed because I am paranoid about something disastrous happening if I don't __________________ Commission Number 352 To do list: 1. Reversing sensors 1a. Headlights polished - DONE! (Magic Mike ) 2. Auto dip rear view mirror 3. Seats replaced - DONE! (thank you Mischief) 7. Bodywork repainted 8. Inlet manifold changed for a working one - DONE! (Magic Mike )

27th January 2022, 16:53	#8
Howie666 I really should get out more....... MG ZT 190+, Trophy Blue Join Date: Nov 2009 Location: Preston Posts: 2,067 Thanks: 1,401 Thanked 309 Times in 195 Posts	Well, when she is traveling under normal circumstances, the voltage stays at around 14. When I stop at traffic lights, it drops as low as 12 sometimes, but increases if I rev the engine. __________________ Commission Number 352 To do list: 1. Reversing sensors 1a. Headlights polished - DONE! (Magic Mike ) 2. Auto dip rear view mirror 3. Seats replaced - DONE! (thank you Mischief) 7. Bodywork repainted 8. Inlet manifold changed for a working one - DONE! (Magic Mike )

27th January 2022, 18:39	#9
Rich in Vancouver Gets stuck in MG ZT-T Join Date: Jun 2016 Location: White Rock, BC on Canada's Pacific Coast Posts: 850 Thanks: 338 Thanked 367 Times in 210 Posts	Sounds like a too-tight timing belt to me as well. The tensioner installation is not straightforward and if the installation instructions aren't followed it can cause issues, either the tensioner roller making contact on the mount or the belt being too tight, resulting in a noise like the one you describe. (Don't ask me how I know! ) Here is a pic of a tensioner in a vise. It is adjusted by rotating it in the direction of the arrow. If you aren't careful the tensioner will slip over centre and the roller will contact the bracket on the lower left. If this happens you can still adjust it so it's no longer in contact but the belt will be too tight. The hole for the hex key must be on the lower right side as shown. If it's not, the tensioner is over center and the tension won't be correct. And here are the instructions that come with the new tensioner. Unfortunately these are often left in the box by technicians. __________________ ZT-T190, Anthracite, LHD, Left the Line on June 24, 2002, Sold new in Switzerland, spent time in Germany, Imported to Canada in September 2021 Last edited by Rich in Vancouver; 27th January 2022 at 19:04..