Air Con Broken - Advice Please

[mrtibbs]

Hi. Last August I had to have a new A/C compressor and drier fitted to my 2.8 GV ((56 reg) and it has worked very well until last Tuesday.

I was travelling up from London and stopped at a motorway services to use the facilities. It was a hot day (25+ degrees C) ^{and the A/C had been keeping the car nice and cold, and I mean cold.... After returning from the services I started the engine and there was a screeching noise from under the bonnet, I had a quick look but didn't see anything obvious, so started driving back home. The A/C was not working and the system was just blowing warm air into the car. I switched the A/C off in case something had frozen and drove a few miles with it off to allow and icing to melt. This did not work and the system has not worked since. When I start the car something is howling from the front right of the engine, making me suspect the compressor.}

^{I returned the car to the garage that had fitted the unit and they checked around thinking the compressor had failed but obviously carrying out a diagnostic test. Apparently the system took a while to pull down to zero and after 45+ minutes under vacuum the vacuum was turned off and the pressure started to rise slowly. Apparently they recovered quite a quantity of refrigerant (not sure of the exact amount) so I guess there is no leak in the system.}

^{The garages conclusion is that the fault is "probably" a failed thermo expansion valve which I am told is bolted to the front bulkhead and will require the engine to be dropped down to allow access, and this will involve about 12 hours work, plus cost of parts. They also said that if the compressor is damaged then it will be because of the failed valve and will therefore not carry any warranty.}

^{It was indicated that the job could cost around £1200 and this is far too much to spend on this car.}

^{I am hopeful that someone can offer some advice as I am unsure that the story I am being told is entirely true.}

^{Does anyone know where this thermo expansion valve is located?}

^{I am looking forward to your replies please.}

 

^{Many thanks}

 

^Keith

[bignev]

Hiya Keith, not sure where on the diesel the valve is located, on the petrol it is on the bulk head low down as the AC pipes pass through it to the evaporator coil in the car, but I would have to think that it's VERY VERY unlikely the engine has really got to be dropped to get at it. 

 

And from my knowledge of air conditioning and refrigeration, it would not be screeching, that sounds like a compressor fault, but if it had lost gas the pressure switch should have prevented it from pulling in the magnetic clutch pulley on the compressor.

A failed valve usually manifests in either icing up of the evaporator coil (in the car) - too much cooling, or not enough cooling. It essentially very cleverly meters the correct flow of refrigerant to the coil.

And they can fail if the dryer isn't doing it's job properly.

Not sure how it could damage the compressor, I'm not THAT good :-)

 

If it took a while to "pull down to zero" or to get to a vacuum state, then there is a leak. And if the pressure started to go up - there is a leak because if there wasn't it would stay at the vacuum it's pulled down to.

It should not take anything like 45 minutes to get to the required negative pressure. On commercial that is done because moisture will boil off at negative pressures, and we don't want moisture in the fridge gas.

 

I've just had a quick look on the Town & Country, and there are various U.S. sites offering to do that job for between $100 and $400, yes Dollars, at your place of work or at home - so I don't reckon they're dropping the engine, do you?

 

Sounds like these guys, sadly, are talking poo. And it actually is as you suspected the compressor.

[mrtibbs]

Thanks for that bignev. I am not a fridge engineer but have spent time around -80 degree freezers so I had a distinct smell of BS when this was being explained to me.

I think that you thoughts are very similar to mine and I thank you for taking the time to respond.

Cheers matey

 

Keith

[bignev]

You're most welcome sir!

 

Do you have any other car AC guys near to you? For more informed second opinion!

[mrtibbs]

You're most welcome sir!

 

Do you have any other car AC guys near to you? For more informed second opinion!

Hiya.

I went to my local garage and they have diagnosed a broken/defective compressor..... What a surprise eh?

I am taking the car back to the original garage and asking them to replace the compressor / drier under warranty and hopefully they won't need to drop the engine or anything else to do that.

I am now of course wary that they will do something silly to my car although maybe I am being cynical....

 

Keith

[bignev]

Oh yes terribly cynical.......

You sound just like me!

Let's hope they are better men than that.

 

As coincidence has it I have had the misfortune to be working on mine this last couple of weeks.

Firstly a leaky water pump,as it turned out not too bad a job at all.

 

Then the power steering pump, new from Rock Auto USA £81 with pulley, delivered in 4 days, super!

Preventative this, a bit grumbly when turning at low speed.

I obviously took the wiper scuttle off which made it an OK access job.

Also exposed the AC expansion valve at that point - piece of cake to get at, passenger side UK on bulkhead, higher than it looks in pictures!

Then a couple I've been putting off since I did the transmission fluid & filter last year - do it again as it obviously hadn't been done for a long time!

And the solenoid pack as well, as it seemed a tiny bit buzzy going into reverse and drive.

So the latter was an arse, made a little easier with the battery tray and coolant bottle out of the way. Rather annoying as it doesn't seem much different.

Fluid easy enough as long as you're prepared for it lashing out when the gasket seal let's go!!!

Edited May 28, 2018 by bignev

[bignev]

Oh just a bit of info chaps, the body of the diesel steering pump is the same - I've had both on my bench - but with a different pulley and inlet pipe connection.

The pipe is easy enough to get off and swap, but the pulley is a completely different matter - ruddy impossible without the correct tools.

 

Rock Auto USA will sell you the body for a lot less than we can get them over here!!

[mrtibbs]

Thanks for the info Bignev. I told the original garage that I had had a second opinion and they have since replaced the A/C compressor under warranty. They found that a rubber "clutch" type thing had seized up and they have fitted an upgraded unit, apparently this has happened previously and the manufacturer was not surprised, but the previous replacement is no longer available

 

Keith

[bignev]

Good stuff matey!

 

But such a shame they didn't "fess up" when you went first time instead of trying to spank your wallet, and wonder why are we mostly cynical and untrusting of garages we haven't got a relationship with.

 

Same in my profession though, heating and gas engineer.Loads of guys might as well roll up on a horse called Trigger with their (lack of) tools in their pocket. Couldn't fix a McDonald's happy meal toy half of them.

[scrufgp]

Thanks for the info Bignev. I told the original garage that I had had a second opinion and they have since replaced the A/C compressor under warranty. They found that a rubber "clutch" type thing had seized up and they have fitted an upgraded unit, apparently this has happened previously and the manufacturer was not surprised, but the previous replacement is no longer available

 

Keith

what did they say about the misdirection and incorrect diagnosis ??

tbh it sounds a bit sketchy and i would definitely be looking for a new garage 

£1200 is not an amount that can be brushed off easily 

when reading the very 1st post on this my 1st comment was get a 2nd opinion !!!

i know that they are not responsible for faulty parts but ffs £1200 on work thats not needed they are responsible for !!!