Help need i have just started to hear a loud noise coming from somewhere in the engine bay that is related to the heating being on.  if i turn the heating off it stops straight away,  and it only seems to come one when they heating kicks in if that makes sense.  ie if i have it at 21c and once it reach that it stops but come back on once it drops below that.  got the car booked in with Skoda dealer for its MOT next Tuesday and was going to ask them to have a look, just do not want to be shocked by anything so any help is much appreciated.

 

Mine occasionally makes a high pitched noise from behind the radio area .... sometimes a rev of the engine and it's gone .... sometimes stays for ages, often nothing at all .... it was suggested on here that it could be an aircon low gas problem and to test if aircon can get ice cold (when the ambient temp is above 6d) which it did, very quickly .... I've put mine down to the spinning fan occasionally whining a bit but please to tell what Skoda say

Mine occasionally makes a high pitched noise from behind the radio area .... sometimes a rev of the engine and it's gone .... sometimes stays for ages, often nothing at all .... it was suggested on here that it could be an aircon low gas problem and to test if aircon can get ice cold (when the ambient temp is above 6d) which it did, very quickly .... I've put mine down to the spinning fan occasionally whining a bit but please to tell what Skoda say

When you say heating, does it come on and off with AC being selected on / off? If so probably an unhappy compressor. Maybe needs evacuating and regassing / oil. Or could be failing, quite a common failure 4yrs+.  If it is related only to heat activity and is not impacted by AC on or off maybe more to do with mixing flaps / heater matrix.

 

PS. it may help to try and describe the noise a bit more fully or record it.

Edited 12 January, 20179 yr by TheClient

My system was tested,re gased/oil etc 14 months ago .... when you say aircon on or off.... I have climatronic set on auto with desired temperature, noise is occasional and like a whistle .... sometimes when you pull up to traffic it's there and fades quickly.... sometimes a simple rev and it stops .... sometimes it keeps whistling for a few minutes ....switch the system off and it stops immediately .... it's barely noticeable with radio on and normal driving .... just when you pull up to a junction or traffic ..it's annoyingly there ....some days nothing at all ..... heating works fine as does ice cold when put on low

There will normally be an AC defeat  even on climatronic  /climate control. Deselect it and see if it still persists. If it goes away with AC off, then it is likely a compressor. They often groan rather than whistle. Or completely fail and then simply don't operate correctly anymore.

Just looked in the manual, pressing econ switches AC off .... I'll try it tomorrow if the noise occurs...thx

Bloody hell....just looked at prices of compressors .....why are the so expensive £350 for a new one and then no doubt a couple of hundred to fit

Yes, pricey. It was the same in Mk5 golfs when mine failed at 40k / under 5 years.  Job probably £500 and up, even from an independent fridgy. Even worse if all the components need changing out due to a failed compressor that sends swarf all through the system.

 

With yours whistling, that is not normally what I've heard from a failing compressor, so it may not be. If you try it with econ on and therefore ac off, and it goes away then it points to AC system but not 100% compressor failure.

 

My fault finding doesn't go a lot further than this on air con, somone else may be able offer more. Alternatively,  good refrigeration mechanic should be able to diagnose the fault for you and then consider what to do from there. Trouble with air con is to work on it needs evacuating and recharging and that means a garage anyway.....

 

Quick google brings back this hella fault finding which has a bit of useful information which mentions whistling and droning under faulty / contaminated expansion valves...

 

https://www.hella.com/hella-tech-world-uk-en/air-conditioning-compressor-2538.html

 

"Often noise can be caused by contaminated expansion valves (figure 10) or orifice tubes." e.g. generate diverse "buzzing, whistling or droning noise", which can be well perceived in the vehicle interior.

Edited 13 January, 20179 yr by TheClient

I was quoted £900, to replace my compressor, by the dealer. Ended up paying about £380, for a chap to come to the house, supply & fit.

Saying that, I was quoted £300 to replace front console bushes by dealer, got it done for £70 at local garage

Yes, pricey. It was the same in Mk5 golfs when mine failed at 40k / under 5 years.  Job probably £500 and up, even from an independent fridgy. Even worse if all the components need changing out due to a failed compressor that sends swarf all through the system.

 

With yours whistling, that is not normally what I've heard from a failing compressor, so it may not be. If you try it with econ on and therefore ac off, and it goes away then it points to AC system but not 100% compressor failure.

 

My fault finding doesn't go a lot further than this on air con, somone else may be able offer more. Alternatively,  good refrigeration mechanic should be able to diagnose the fault for you and then consider what to do from there. Trouble with air con is to work on it needs evacuating and recharging and that means a garage anyway.....

 

Quick google brings back this hella fault finding which has a bit of useful information which mentions whistling and droning under faulty / contaminated expansion valves...

 

https://www.hella.com/hella-tech-world-uk-en/air-conditioning-compressor-2538.html

 

"Often noise can be caused by contaminated expansion valves (figure 10) or orifice tubes." e.g. generate diverse "buzzing, whistling or droning noise", which can be well perceived in the vehicle interior.[/size]

This is fab.... many thx for the info.... made no noise at all today .... but looking at the article ....expansion valves sounds the most likely as the noise is generally in the cabin rather than engine bay