Motor Ombudsman Advice

AdrianC

sambobo wrote: »

At the heart of the air conditioning unit of a car is the compressor that pressurizes the refrigerant and pumps it through the A/C system. It derives its power directly from the engine flywheel and, in a similar way to the drive chain of the car, a clutch controls its operation.

Umm - no. It doesn't get its power from the flywheel, and it's a clutch - but not the same one.

It's driven from the serp belt at the other end of the engine to the flywheel, same belt as drives the alternator, and the electro-magnetic cluch is an integral part of the compressor, rather than the friction plate between engine and transmission.

B'sides, your aircon problem was almost certainly a gas loss caused - first time - by means unknown, and second time probably by some small foreign body that got introduced into the filling valve during the regas, leading to the gas escaping. If they've not done a thorough vac pull-and-hold test, then used UV dye to trace any leak, then it may well be both are the same cause - foreign object damage to the condenser, probably the single most common cause of gas leaks on newer cars, and not something that's EVER warranty covered.

BeenThroughItAll

sambobo wrote: »

At the heart of the air conditioning unit of a car is the compressor that pressurizes the refrigerant and pumps it through the A/C system. It derives its power directly from the engine flywheel and, in a similar way to the drive chain of the car, a clutch controls its operation. These two parts are the hardest working components in a vehicle's A/C system, and maintaining them in good working order is essential to its efficiency.

The air conditioning compressor is run by a belt driven by the crankshaft - at the opposite end of the engine to the clutch and flywheel. The clutch and flywheel sit inside the bell-housing of the gearbox, and there is no interaction whatsoever between the clutch and flywheel and the air conditioning.

The two faults are NOT related in any way.

The clutch/flywheel have worn out. Not warranty covered.

The air conditioning fault probably results from the common (but incorrect) behaviour exhibited by many users who don't understand that air CONDITIONING <> air COOLING. As a result, they only turn on the A/C in hot weather - if it's not regularly used, like so many things, its performance degrades and eventually it stops working when seals, compressor bearings and shaft seals dry out, shrink or crack as a result of not being supplied with the lubricating oil which is borne within the refrigerant.

Chance of getting problems sorted under warranty? IMO, zero.

On the subject of your earlier post, the expanded description with context is much easier to understand.

sambobo

The air conditioning compressor is run by a belt driven by the crankshaft - at the opposite end of the engine to the clutch and flywheel. The clutch and flywheel sit inside the bell-housing of the gearbox, and there is no interaction whatsoever between the clutch and flywheel and the air conditioning.

Apart from the exchange of energy. As I found out earlier.

The two faults are NOT related in any way.

or they are 100% related as is my point.

The clutch/flywheel have worn out. Not warranty covered.

The Flywheel has become damaged and it may have caused the clutch to be damaged - both are covered by warranty as advised by the garage. (clutch is normally exempt from warranty unless damage is caused by manufacturing defect)

The air conditioning fault probably results from the common (but incorrect) behaviour exhibited by many users who don't understand that air CONDITIONING <> air COOLING. As a result, they only turn on the A/C in hot weather - if it's not regularly used, like so many things, its performance degrades and eventually it stops working when seals, compressor bearings and shaft seals dry out, shrink or crack as a result of not being supplied with the lubricating oil which is borne within the refrigerant.

probably correct - I am not aware of anyway to override the air conditioning in my car and it comes on regularly without me having to control it. The air being cooled is only noticable on days when it is hot outside.

Chance of getting problems sorted under warranty? IMO, zero.

100% chance as already stated numerous times

On the subject of your earlier post, the expanded description with context is much easier to understand.

many thanks for all your contributions and taking the time to read it for me. Im feeling very well supported here :beer:

sambobo

Thanks for your response. Ultimately I will wait for the garage to diagnose the extent of the damage caused by the flywheel not operating correctly. But I assume, as found by other VW experts that fixing the flywheel will fix the air con.

Umm - no. It doesn't get its power from the flywheel, and it's a clutch - but not the same one.

It's driven from the serp belt at the other end of the engine to the flywheel, same belt as drives the alternator, and the electro-magnetic cluch is an integral part of the compressor, rather than the friction plate between engine and transmission.

These two paragraphs seem contradictory to me. It seems like you think that one end of the crankshaft is isolated from the flywheel at the other? I would assume that there is no isolation.

B'sides, your aircon problem was almost certainly a gas loss caused - first time - by means unknown, and second time probably by some small foreign body that got introduced into the filling valve during the regas, leading to the gas escaping. If they've not done a thorough vac pull-and-hold test, then used UV dye to trace any leak, then it may well be both are the same cause - foreign object damage to the condenser, probably the single most common cause of gas leaks on newer cars, and not something that's EVER warranty covered.

This could be true actually, I will amend the letter to ombudsman because the First problem with the air con probably was caused by the service person graunching something or a valve and causing a gas leak. This sounds about right as the air con completely stopped working. Since then, and currently, the air con is working intermittently which suggests there is some gas left in the system. and all signs point to flywheel causing this problem. Note that it feels like - though difficult to confirm that the air con doesnt work when idling and at low speeds but ok at faster speeds. It was 100% working all the time before i took it to get serviced.

BeenThroughItAll

sambobo wrote: »

Apart from the exchange of energy. As I found out earlier.

or they are 100% related as is my point.

I'm out. You're clearly an expert.


Good luck with it. I still don't believe for one minute you'll end up getting a clutch and flywheel under warranty.

sambobo

Again, many thanks for all your contributions, I am not an expert on car mechanics but do have a university level understanding of engineering in general. I am mainly here for advice on Money, and the matter of consumer rights rather than the mechincal aspects - that im certainly not an expert on but was hoping that some people here would be able to chip in! Although, your questions about the mechanics will certainly help me to use the correct terminology if and when i need to argue the case.
But it would be extremely unfair for VW not to fix this under warranty seeing as they already booked it in on Thursday for a warranty repair after diagnosis and, further, the flywheel is covered under the terms of the warranty. I am slightly nervous that they wont fix the clutch but they have already told me that this is a warranty replacement too so that just about covers that one.

Ill take this moment to remind everyone that my gripe is neither with the fact that the car has a fault, nor with the fact that it will be fixed under warranty, but my case is about not providing a courtesy car, drive to work or suitable compensation for hire car/public transport as advertised.

On that side of things your "wall of guff" comments were very helpful so i am very grateful for that!

AdrianC

sambobo wrote: »

But I assume, as found by other VW experts that fixing the flywheel will fix the air con.

It won't.

These two paragraphs seem contradictory to me. It seems like you think that one end of the crankshaft is isolated from the flywheel at the other? I would assume that there is no isolation.

They're connected. The entire rest of the engine is in the middle. If they weren't connected, you'd have FAR bigger problems.

But that doesn't mean the two problems are in any way related.

sambobo

But that doesn't mean the two problems are in any way related.

Ok, if the two are not related then:
A) Explain how the compressor belt can turn if the flywheel cannot.
explain how the compressor can remain operational if the belt is not turning.

Also I refer back to the point about the alternator, possibly though i still think unlikely, if the flywheel is not turning consistently then, perhaps there is not enough voltage on the alternator to enable switching of the electromagnetic clutch in the compressor.

AdrianC

sambobo wrote: »

Ok, if the two are not related then:
A) Explain how the compressor belt can turn if the flywheel cannot.

If the flywheel wasn't turning, how did you get the car to move under its own power?

explain how the compressor can remain operational if the belt is not turning.

If the serp belt wasn't turning, you'd have plenty of other problems.

Also I refer back to the point about the alternator, possibly though i still think unlikely, if the flywheel is not turning consistently then, perhaps there is not enough voltage on the alternator to enable switching of the electromagnetic clutch in the compressor.

Again, if there was insufficient voltage for the compressor clutch, you'd have plenty of other problems. The car wouldn't start, and you'd probably need to use the key in the physical lock to open the door... But the alternator is, at least, driven by the same belt as the compressor.

OK, I think we need to go back a step or three...
This is a picture of a Polo 1.2TSI engine.


The image is viewed from approximately the driver's side headlamp. It clearly shows the black serp belt, going around the air con compressor (low), and the alternator (above it).

The flywheel is the other end of the engine, not shown.

This image is the other end of the engine, viewed from around the front edge of the passenger side front wing.

You can see the back of the alternator and compressor. The flywheel is removed in this image, and you can see the back of the crank (the round face with a ring of holes). The flywheel bolts to the crank, the clutch bolts to the flywheel, and the whole lot is then hidden by the gearbox.

This animation shows the job of the flywheel and clutch.
https://www.youtube.com/watch?v=pqF-aBtTBnY

The ONLY other thing that's connected to the flywheel is the starter motor (which rotates the engine via that outer ring of teeth)

sambobo

If the flywheel wasn't turning, how did you get the car to move under its own power?

First of all, by changing the subject i assume you are agreeing that the two are directly related.
I cant get the car to move under its own power all the time. hence, why I'm so peed off!
Before the clutch stopped working, the ac was working intermittently and the clutch was working intermittently.

Again, if there was insufficient voltage for the compressor clutch, you'd have plenty of other problems. The car wouldn't start, and you'd probably need to use the key in the physical lock to open the door... But the alternator is, at least, driven by the same belt as the compressor.

Yes i see what you are saying here - i did say that its possible that it was alternator problems. I know this is not your main point but obviously the key locks run off the battery when engine is off and do not require alternator voltages. I'm suggesting that the compressor clutch may require higher voltages to operate than the door latch solenoids, these higher voltages normally being provided by the alternator when the car engine is running. same applies to starter motor which runs off the battery voltage rather than the alternator voltage. I assume that very soon the battery will no longer have enough charge to start the car because if the alternator is not providing enough charge voltage.


I completely agree with all your other explanations and diagrams, that was never in question but nice pictures! A flywheel is bolted to the crank and the belt is driven off the crank at the other end. Therefore if the flywheel stopped turning the belt would stop turning and therfore any devices driven by the belt would stop working. Exactly what is happening in my car.

Again thanks for your contributions here [cheers], perhaps we can get back to the MSE aspects of this rather than the mechanical.