Strange noise is driving me mad.

[bigcarpjohn]

Hi all,

My van has been making a strange noise that's been driving me mad. It's not a metallic rattle and it's not a squeak – more of a throaty/vibrating noise. It sounds like it's coming from the middle of the engine bay. It's quite subtle, but I'm the type who can hear grass growing!

It's most noticeable on the motorway at low RPM. For example, with cruise control set at around 60mph, when the van comes to a hill and is under load, I can hear it. I can also hear it when stationary at traffic lights.

Today, while sitting at some lights, I started trying to narrow it down. The van is a DSG T6 180.

• Put it in neutral – noise remained.
• Turned OFF the A/C but left the blower running – noise remained.
• Turned the blower off completely – noise disappeared.
• Turned the blower back on – still no noise.
• Turned the A/C back on – noise returned.
• Turned the A/C off again – noise stayed there until I switched the blower off.
• Once the blower was switched off and then back on, the noise disappeared again (until I turned the A/C back on).

The noise also disappears if I increase the RPM.

Any thoughts on what could be causing this?

 

[Dellmassive]

I'm thinking AC compressor clutch bearing.

See if you can get a video clip on your phone.

The closest you can get to the AC compressor is under the van, front. Drivers side..... They normally make a sqweel sound.

Other options are any pully in the auxiliary belt.

 

[Dellmassive]

What year and how many miles?

 

[DXX]

I'm thinking AC compressor clutch bearing

No AC clutch on a T6, maybe you mean the alternator clutch pulley?

 

[bigcarpjohn]

Its 106k 2016

 

[DXX]

De-tension the auxiliary belt and check the action of the alternator clutch pulley by hand. A defective alternator clutch pulley will damage the aux’ belt tensioner.
I can’t say if that’s the cause as I don’t know what a ‘throaty vibrating noise’ is.
You could record it and post it via YouTube etc.

 

[willythepooh]

My van has a cyclic noise similar on the lowest fan setting (1).
Very annoying when you tune in.

 

[whodat]

Something (small bit of plastic wrapping or similar) caught in vent/fan? Sometimes gets caught in fan? warped rubber grommit around that area?
Have you changed the Aircon filter? 10minute job - just make sure you know which way round it came out. If that is dirty - could it cause fan to work harder?

Keep us updated.

 

[DXX]

My van has a cyclic noise similar on the lowest fan setting (1).

Best not use fan setting 1 as it can lead to the thermal fuse blowing on the fan speed resistor pack.

 

[willythepooh]

It hasn’t yet after 52,000 miles.

 

[whodat]

My van has a cyclic noise similar on the lowest fan setting (1).
Very annoying when you tune in.

Yeah - unfortunately my van has that on setting 2 which is the one it is at all the time. (3 is too loud and blowy and 1 turns out breaks the van!)

 

[bigcarpjohn]

De-tension the auxiliary belt and check the action of the alternator clutch pulley by hand. A defective alternator clutch pulley will damage the aux’ belt tensioner.
I can’t say if that’s the cause as I don’t know what a ‘throaty vibrating noise’ is.
You could record it and post it via YouTube etc.

Ill try my best