Heat pump vibrations and noise

Faults and Technical chat for the Skoda Enyaq
Sandro
Posts: 15
Joined: Wed Feb 02, 2022 3:48 pm

Post by Sandro »

RichR wrote: Mon Feb 07, 2022 4:16 pm Yes, you'd think that you should if it was the compressor causing them when under load - which is why I'm unsure that it's the source of the vibration.

Only a VW/Skoda engineer who actually knows the system properly would be able to diagnose this I think.
Well the problem is that the Skoda shop was thinking they knew but I called them today and informed them that the new pump is the same and they are clueless to why. Question is what other motor/pumps are there that are connected to the heating?

Because the thing is that if I go up step by step with the heating you clearly hear some type of pump starting and working up the RPM to a point that it starts vibrating.

User avatar
RichR
Posts: 1917
Joined: Thu Mar 11, 2021 11:53 am
Location: South end of North Yorkshire

Post by RichR »

There is the compressor, and there are various fans. Those are the only rotating parts in the cabin heating system. I'd like to think that given you can see and touch the compressor, they would have tried to feel if it was vibrating.
Enyaq iV 80 Sportline, Energy Blue, Assisted Drive Plus, Infotainment Plus, Convenience Plus, Comfort Seat Plus, Transport Pack, Heat Pump, ME3.2, Built Nov 2021.
Sandro
Posts: 15
Joined: Wed Feb 02, 2022 3:48 pm

Post by Sandro »

RichR wrote: Mon Feb 07, 2022 4:42 pm There is the compressor, and there are various fans. Those are the only rotating parts in the cabin heating system. I'd like to think that given you can see and touch the compressor, they would have tried to feel if it was vibrating.
Thanks man. I am baffled by the fact that you only hear the pump rev up and work when heating is chosen, but when the cooling is chosen you hear nothing besides the fans blowing air even when AC is on?
User avatar
tiger tony
Posts: 241
Joined: Sat Jul 24, 2021 7:58 am
Location: Banbury, Oxon, UK

Post by tiger tony »

Noisy mechanical expansion valve ? ?

I've experienced this in past, when I over gassed an A/C system !

But I believe the ones on this system are electrically operated.
Enyaq iV60, Loft, Race blue, 20" Vega's, ME3.0 updated.
User avatar
RichR
Posts: 1917
Joined: Thu Mar 11, 2021 11:53 am
Location: South end of North Yorkshire

Post by RichR »

That's an idea - there are several solenoid actuated expansion valves which it opens depending on what mode it's in. It could be one of those fluttering maybe?

But I'd like to think that when it went in with a 'noise and vibration present' issue, they'd have reproduced it, and gone round with a mechanic's stethoscope (or a long screwdriver in the ear!) to try to pin down where it's coming from. Or were all those old skills that we used to do to find the noisy tappet or bearing on engines a thing of the past?

I certainly wouldn't be draining a very high pressure CO2 system and isolating a 400V supply to replace the compressor unless I was absolutely certain that was the cause of it. I do notice that the workshop manual says to carry out a calibration procedure, wonder if that is required to tune it somehow?
Enyaq iV 80 Sportline, Energy Blue, Assisted Drive Plus, Infotainment Plus, Convenience Plus, Comfort Seat Plus, Transport Pack, Heat Pump, ME3.2, Built Nov 2021.
User avatar
tiger tony
Posts: 241
Joined: Sat Jul 24, 2021 7:58 am
Location: Banbury, Oxon, UK

Post by tiger tony »

Nothing wrong with the good old long screwdriver to the ear ! Best tool for diagnosing rumbling bearings and strange noises :lol:

But I guess a faulty expansion valve would probably show up other problems, like lack of cooling or heating ?
Enyaq iV60, Loft, Race blue, 20" Vega's, ME3.0 updated.
Sandro
Posts: 15
Joined: Wed Feb 02, 2022 3:48 pm

Post by Sandro »

So I have reported the issues to the shop. Thry were sorry to hear that it is still there and they will try to check other parts and valves. They suspect that perhaps one of the valves dosen't open properly and that an overpressure builds up and causes the entire system to vibrate like crazy.

The sad part is that the new pump sounds at lower RPMs like a small petrol engine "brum brum brum".
User avatar
RichR
Posts: 1917
Joined: Thu Mar 11, 2021 11:53 am
Location: South end of North Yorkshire

Post by RichR »

It's good that they are going to examine the whole system, not just the compressor. I've tried having mine set to a high difference compared to ambient (although it's now around 8-10C here), with the battery cold, and with it hot and the car stationary. Apart from a slight whine I can't really hear anything unless I open the windows. There's no vibration at all through the steering wheel or floor that I can detect. This is with the system in full automatic mode - I don't tend to use manual mode much on any modern car.

What you're describing does not sound normal, and it'd probably not from the fans - which only leaves the valves or compressor. And in theory the compressor is good (though we don't know if they did the calibration step mentioned in the documentation). Let's hope they locate the problem - keep pushing until they do though, as I'm sure there are thousands of Enyaqs with the heat pump system that don't have this issue, so it would be good for them to get Skoda head office involved to issue a technical bulletin telling other garages how to resolve it if it does start happening on other cars.
Enyaq iV 80 Sportline, Energy Blue, Assisted Drive Plus, Infotainment Plus, Convenience Plus, Comfort Seat Plus, Transport Pack, Heat Pump, ME3.2, Built Nov 2021.
Sandro
Posts: 15
Joined: Wed Feb 02, 2022 3:48 pm

Post by Sandro »

Thanks for all the info.

Here is a clip where I try to capture the sound of the pump. It is extremely hard to do, and I cant film the vibrations you feel in the car. The first 10 seconds you hear how the pump starts working harder and the sound is like a small petrol engine. Turn up the volume.

Please note that in this case I set the temp at 29C just to start the pump for the video. It starts working and vibrating from about 18-21C where I often set the temperature.

User avatar
gap998
Posts: 98
Joined: Thu Nov 18, 2021 10:48 am
Location: Wales, UK

Post by gap998 »

RichR wrote: Wed Feb 02, 2022 7:29 pm The heat pump compressor is almost exactly the same as the aircon compressor in the normal system. The difference is that the working fluid is R744 instead of R1234yf, and there are several additional valves and heat exchangers. The liquid coolant system is also almost the same - it’s this that the heat pump extracts heat from to heat the cabin. It’s just got a heat exchanger in it for that to happen.

See my ‘how the heat pump works’ thread 🙂
So when the dealer says my AC compressor is faulty he actually means the Heat pump, or are there two separate compressors? - I must read your thread.
Enyaq iV60 Loft 100kW Charging, Arc. Silver, Regulus 19", Heat Pump, Ass'd Drive Pack, Parking+, Drive Sport, Conv.+, Transport Pack

Order 2-11-21 - Built 22-08-22 - Collected 28-09-22 - Drive Fault 4-10-22 - Back to Dealer 18-10-22 - Fixed 17-11-22
Post Reply

  • You may also be interested in...
    Replies
    Views
    Last post