2013 D4 Air Conditioner Issue

[letherm]

Hi Guys.

The aircon in my D4 is not working as well as it used to. Noticed it over the last several days. It still cools but is not cold like it normally is. I've got a GAPIID tool and looked at the ventilation figures but it's all Greek to me. Out of warranty so I'm on my own from that point of view.

Any ideas or suggestions?

Martin

[DiscoMick]

Get it serviced. Could be something as simple as a blocked filter or needs regassing.

[BradC]

Get it serviced. Could be something as simple as a blocked filter or needs regassing.

All automotive compressors have a rotary mechanical seal. They *all* leak. Some leak faster than others. With the global trend towards smaller and smaller gas charges, the leak as a percentage of overall charge becomes quite significant.

I did our D3 last year and it was 150g short. That extra 150g of gas in a half-kilo system makes a huge difference in available capacity on a hot day.

I recommend people get their system re-gassed every 2 or 3 years. As the charge level falls, and well before it falls enough for you to notice, it starts to impede oil circulation and the lubricant slowly migrates to the evaporator starving the compressor. When the compressor goes, it's a compressor, condenser, dryer, TX valve, line flush, evaporator flush. Messy and very expensive.

Yes it's a worst case, but a hundred bucks for a re-gas every couple of years is cheap insurance.

[DiscoJeffster]

Failing that the valve that controls the variable compressor is known to fail. LR suggest a compressor replacement however the valve can be replaced independently. I have one on my shelf ready to be installed

[scarry]

Failing that the valve that controls the variable compressor is known to fail. LR suggest a compressor replacement however the valve can be replaced independently. I have one on my shelf ready to be installed

Thats the most common issue with theses vehicles.

Auto air compressors have extremely good seals these days, and don't weep like the older types.If the gas charge has dropped there is more than likely a leak somewhere that needs repairing.A trace of oil on the pipework or fittings is a good indication where the leak is,although leaks can appear dry at times with no trace of oil.

A trip to a good auto AC guy is the go.

[DiscoJeffster]

Thats the most common issue with theses vehicles.

Auto air compressors have extremely good seals these days, and don't weep like the older types.If the gas charge has dropped there is more than likely a leak somewhere that needs repairing.A trace of oil on the pipework or fittings is a good indication where the leak is,although leaks can appear dry at times with no trace of oil.

A trip to a good auto AC guy is the go.

I took mine to the AC dudes and they diagnosed the control valve. Unlike a VW model that suffer from Black Death, the prognosis was faulty pressure control valve. The pressures aligned to a working system however the 10 minute delay to cooling and the overall lack of cooling pointed to the control valve.

[letherm]

Thanks for the info guys.

I was thinking along the lines of a re-gas but threw it out there for your collective wisdom. Thought there may possibly have been a simple clean a filter job that I may have been able to do myself that I was unaware of. Funny how they hit a tipping point and you notice the change. Shouldn't complain, it's over 5 years old now.

Anyone in Sydney know a good AC workshop? I live near Parramatta but would rather travel and get good workmanship and service.

Martin

[PerthDisco]

Hi Letherm as DiscoMick suggested do you know about the pollen filter behind the glovebox?

I’m interested to know from others if this could get so blocked on a dusty trip as to restrict cooling performance?

I imagine the air flow would be noticeably restricted.

[letherm]

Hi Letherm as DiscoMick suggested do you know about the pollen filter behind the glovebox?

I’m interested to know from others if this could get so blocked on a dusty trip as to restrict cooling performance?

I imagine the air flow would be noticeably restricted.

Hi PerthDisco.

Not that simple unfortunately. It was replaced at the annual service in November. The dealer has done it every year and I drive in the city so it's probably not the cause. Then again, Sydney has its share of pollution. I'll check it out though just in case.

Martin

[DiscoMick]

Is the heater completely closed off when the control is set to cool?

[DiscoJeffster]

Try a regas as step one. From there it’s the valve. Contact me for the part and order details

[letherm]

Is the heater completely closed off when the control is set to cool?

Mine is an HSE and I just set the desired temperature for passenger and driver via the dials either side of the console. Usually I just leave it on Auto and A/C and it does its own thing. To answer your question, I assume it is internally shut off as there is still cool air coming out of the vents. It was 41 outside and I had the temp set at 16 and then put it on 20 thinking the difference in temp might be outside its working range but it has handled heat before.

Martin

[veebs]

The bi annual checkup is a good idea - can anyone recommend a good place in Perth?

[BradC]

The bi annual checkup is a good idea - can anyone recommend a good place in Perth?

I've had good service from Autocool on Lord st. I do my own work, but they've always been good for parts and advice. Old school tradies.

[DiscoJeffster]

I've had good service from Autocool on Lord st. I do my own work, but they've always been good for parts and advice. Old school tradies.

Quoted me nearly $800 to change the AC compressor valve. Got the valve for $100 and will fit myself. I’ll factor in a couple of hundred to scavenge and refill the refrigerant to change the valve myself. Couldn’t justify that sort of money for a relatively simple task.

[BradC]

Quoted me nearly $800 to change the AC compressor valve. Got the valve for $100 and will fit myself. I’ll factor in a couple of hundred to scavenge and refill the refrigerant to change the valve myself. Couldn’t justify that sort of money for a relatively simple task.

I've done 3 in my driveway. It can be a "relatively simple task". It can also turn into a pig of a job if things go wrong. Like I said, I can't vouch for their labor as I do it myself, but they've always been good for advice and parts.

if it's any consolation my brothers VW mech quoted him $800 for the same job. That one was a doozy as the valve got stuck and there's not much room between the valve and the radiator on a MK 6 golf.

[DiscoJeffster]

I've done 3 in my driveway. It can be a "relatively simple task". It can also turn into a pig of a job if things go wrong. Like I said, I can't vouch for their labor as I do it myself, but they've always been good for advice and parts.

if it's any consolation my brothers VW mech quoted him $800 for the same job. That one was a doozy as the valve got stuck and there's not much room between the valve and the radiator on a MK 6 golf.

I believe one trick is to scavenge, remove circlip on the valve, then pressurise the system with nitrogen. This literally blows the valve out of the compressor, then replace valve, scavenge to vacuum and refill refrigerant. Sound like a few trips to the AC place though. I’ll probably get them to scavenge and refill to 0 atm with nitrogen so I don’t have to fight the vacuum of the system when trying to remove the valve [emoji52]

[BradC]

I believe one trick is to scavenge, remove circlip on the valve, then pressurise the system with nitrogen. This literally blows the valve out of the compressor, then replace valve, scavenge to vacuum and refill refrigerant. Sound like a few trips to the AC place though. I’ll probably get them to scavenge and refill to 0 atm with nitrogen so I don’t have to fight the vacuum of the system when trying to remove the valve [emoji52]

Too much nitrogen and you push a load of oil out of the compressor when the valve comes out. It's a delicate balance, but yeah there is zero chance of getting the valve out under vacuum.

I wouldn't drive the car with a vacuum or nitrogen in there. Even at minimum displacement the compressor is still pumping gas and due to the serpentine belt you can't just pop the belt off to stop it. You'll end up ejecting the lubricant from the compressor and not having any gas to bring it back.

Once you've changed the valve you will be pushing humid air around the system. You'll want to get a vacuum on it as soon as is practical after putting the new valve in.

[DiscoJeffster]

Presumably then Brad you’ve removed the gas yourself in your drive, else what’s your method?

[BradC]

Presumably then Brad you’ve removed the gas yourself in your drive, else what’s your method?

Yeah, I have all the gear. Check your pm.

[kelvo]

Is the heater completely closed off when the control is set to cool?
The heater matrix is full water flow all the time, a blend flap is used to stop the cabin air going over the matrix when heat is not required.

[Petetheprinta]

I’ve had a quote for $980 to replace valve by an Indy here in Adelaide. Anyone know someone here who can do it at a better price. I don’t have the wherewithal to do it myself.

[DiscoMick]

Mine is an HSE and I just set the desired temperature for passenger and driver via the dials either side of the console. Usually I just leave it on Auto and A/C and it does its own thing. To answer your question, I assume it is internally shut off as there is still cool air coming out of the vents. It was 41 outside and I had the temp set at 16 and then put it on 20 thinking the difference in temp might be outside its working range but it has handled heat before.

Martin16 is very low and asking a lot of the system. Have you tried 24?

[BradC]

16 is very low and asking a lot of the system. Have you tried 24?

If its 41 outside there will be zero difference between 16 & 24. Either way the system will be running flat out to try and keep up.

If you want an idea as to how hard it'll be working, check out the system pressure, interior temperature and left/right solar loads on the IID.

[DiscoMick]

Yeah should maybe aim for about 10 below the ambient temperature.
The climate control in our Mazda 2 seems happy set on 24.

[letherm]

16 is very low and asking a lot of the system. Have you tried 24?

I don't normally run it at 16 but was trying to see if it would get colder. I suppose on average I run at 20 to 22. My wife likes to live in a fridge so I acclimatised. [smilebigeye] That said, it's never been a problem before.

Martin

[letherm]

If you want an idea as to how hard it'll be working, check out the system pressure, interior temperature and left/right solar loads on the IID.

What would be a normal reading? I did pull up some data but didn't know whether it was good or bad. From memory there was a pressure reading of around 1600.

Martin

[BradC]

What would be a normal reading? I did pull up some data but didn't know whether it was good or bad. From memory there was a pressure reading of around 1600.

Martin

Ok, this started out as a quick pt post, but it has rapidly grown. Excuse the ramble.

"Normal" is relative. That pressure is the high side pressure of the system and is a direct measurement of the saturated condensing temperature.
This can be easily translated using a pt chart for r134a.
Pressures in kPA, Temp in C. Roughly rounded


900

39



1100

46



1300

53



1500

58



1700

63



1900

68




The condenser is designed roughly for a 10/15C split above ambient. So at design conditions on a 40C day you'd be expecting to see 50/55C saturated condensing temperature (SCT), or ~1200-1360kpa.
This is going to be at road speed with a large airflow over the condenser.
Sitting at traffic lights that will rise considerably, and at low cabin heat loads it'll fall.

At the same conditions, your evaporator temperature is going to target somewhere around ~2C. At traffic lights when the SCT is high and the compressor speed is low that will rise (I've seen 9C). Get the revs up a bit and it'll drop back down. When the airflow over the condenser increases it'll fall further.

The compressor is just a normal gas compressor. It takes gas at a low pressure and compresses it up to a higher pressure. It suffers the same losses as any other compressor with regards to valve efficiency, blowby and dead space in the head. So, the higher the output pressure, the lower the efficiency of the compressor.

That translates as the lower the SCT (head pressure) the more gas the compressor will move for the same displacement. So the system always works better at speed as you have a lower condensing temperature resulting in a lower head pressure.

The condenser serves 2 roles. It condenses the hot vapor into warm liquid, and it subcools that warm liquid below the condensing temperature. It does this because at the correct charge level there is enough liquid to both fill the evaporator and back up some liquid into the condenser. As the charge level falls, the amount of liquid in the condenser is reduced and therefore the degree of subcooling falls. When that reaches the point you start to feel it there is no subcooling and the liquid reaching the TXV is already starting to boil. That reduces the flow through the TXV and starves the evaporator of liquid, reducing its capacity.

You'll see that as an increased evaporator temperature, and a reduced high side pressure. As the evaporator extracts less heat from the air, the refrigerant has less heat to reject into the condenser. This'll result in a lower SCT as with less heat to reject the refrigerant is easier to condense.

That leads to the final element, which is oil flow. The compressor ejects oil in the discharge gas. It works its way through the condenser by gravity and condensing refrigerant droplets where it is carried by the subcooled liquid into the evaporator. In a properly charged system the refrigerant in the evaporator is violently boiling such that at the evaporator exit there is a superheated vapor of refrigerant and entrained oil leaving. As the charge level falls, the boiling moves down from the top of the evaporator. This reduces the amount of oil ejected from the top of the evaporator (as it has time to start to fall out of suspension before it leaves) and so more oil stays trapped in the evaporator rather than making its way back to the compressor. The compressor ends up getting starved of oil resulting in mechanical damage.

Back to the condenser. As it performs 2 roles (condensing and subcooling) there is a balance between these roles, and the specified refrigerant volume (weight) is designed to hit the right balance as determined by the manufacturer. When you charge a system there are 2 ways to do it :
- By weight. Pull all the gas out (weigh it to see how much was left) and put the right qty back in.
- By subcooling. Get the system running at design parameters, measure the high side pressure and liquid temperature leaving the condenser, and adjust the charge until you have the correct subcooling level. For this you need the design parameters and correct figures to go by.

Too much gas and you raise the SCT so the compressor has to work harder. Too little gas and you lower the subcooling which will affect the TXV and cause reduced evaporator capacity.
This is why everyone does it by weight. It's the easiest method to know you have it right.

Sorry, that got a bit longer than I had intended.

[DiscoJeffster]

geoffx19 found this link online, specifically related to the valve issue and there is now a part number for it.

https://testing-public.carmd.com/Tsb/Download/106795/LTB00693NAS1

[4bee]

Sorry, that got a bit longer than I had intended.



That remark is usually followed by, "Sorry, what was the question?"

Well explained. [smilebigeye]

[letherm]

Ok, this started out as a quick pt post, but it has rapidly grown. Excuse the ramble.



Thanks Brad. I need to read that a few times for it to sink into my old brain but I got the gist of it. Since I first raised this thread after a plus 41c day I've had a few other less extreme days. Yesterday was about 35c and the air con was fine set at 20. Today it is about 28 and the air coming out of the vents was cold as normal with a temp setting of 20. I dropped it to 16 to try it out and it was very cold. Bottom line I suppose is I pushed the air con beyond its limits on a really hot day. I was going to take it to an a/c specialist but I will bide my time to see what happens. That said I took on board a previous comment about getting it serviced regularly.

Thanks everyone for all of the comments.

Martin

[BradC]

Bottom line I suppose is I pushed the air con beyond its limits on a really hot day.

But that's the thing. There is no such thing as "beyond its limits". There are all sorts of safety mechanisms built in that ensure you can run it as hard as you like and it will run as hard as it considers safe. If it's low on gas it will have a reduced capacity for moving heat, so if it's not keeping up and it hasn't seen a re-gas in a few years the likelihood is could do with one. It's certainly the cheapest place to start.

Last Sunday it hit 46 at our place (per our weather station. car indicated 47 on the dash) and the AC in the D3 handled that nicely. Sure, it only got the cabin down to 30, but between having nice dry air and <10C from the vents it was quite comfortable.

[4bee]

Sure, it only got the cabin down to 30, but between having nice dry air and <10C from the vents it was quite comfortable.


ONLY 30 with a 46c amb? [bighmmm]

Plus, one doesn't need it too cold as the contrast when exiting the vehicle is too great & in turn that can be uncomfortable & with a bit of humidity a 'wet' skin. IMHO you just need a happy balance.

[kevo78]

Hi all, I've just replaced the variable valve with out much success. The left passenger vents feels cool at least but the drivers side is warm. I'm assuming I now have a fault with a blend motor not closing fully but how do access this to prove? i'm trying to get the dash apart without much luck. This is on a 2013 D4. any Ideas?

[letherm]

A bit late with an update but here it is. I put the car into our long time local mechanic. Result was that the compressor is not working as well as it should but is still quite serviceable and all parts would be being lubricated as they should be. They did the usual tests looking for leaks and regassed it. It is a bit better but not as quick as when I bought it to start cooling. Reasonably happy with the cooling now and will wait and see. As suggested I will get it serviced yearly until it needs replacing etc.

Martin

[DiscoMick]

If it's lowering the ambient temperature by about 15 degrees it's working normally, I think.

[RobA]

Well this thread has proved to be a useful diagnostic discussion as usual. Over Christmas we had a few warm AC moments mostly when towing through the Adelaide Hills but also when back in Adelaide. Not regular events but noticeable.

Had the car serviced at Sovereign last week in preparation for another trip to WA and asked them to check the AC. Whilst it tested OK and no fault evident with the valve I took the view that preventative maintenance and replacement is better than losing the AC for 3 months in outback WA.

Well the difference in the performance of the AC was immediately a noticeable improvement to the point where 22C we cold rather than "sort of cool"

Car is an MY 15 TDV6 and has travelled 95,000km with most of that towing and around 75% or more off bitumen so AC operating.

So looking forward to several more years of reliable AC operation

Rob

[haydent]

AC is making hot air, first photo is with AC off, second is with it on, any suggestions ? 2010 l320 tdv8
Natrad says its got enough gas but that compressor wasnt kicking in (yet diagnosing at home it appears it is) , could they be wrong about gas level needed, or dead compressor or valve maybe as youd think it would make hot air just from not quite full gas level.

181923
181924

[DiscoJeffster]

The compressors are known to fail. Very common.

[LuckyLes]

Those figures would seem to indicate that the compressor is not pumping the refrigerant. I am pretty sure that the compressor is a variable displacement type. These are operated by an internal control valve which do fail. The compressor may or may not be repairarable by replacing this valve.
Cheers
LuckyLes

[scarry]

Those figures would seem to indicate that the compressor is not pumping the refrigerant. I am pretty sure that the compressor is a variable displacement type. These are operated by an internal control valve which do fail. The compressor may or may not be repairarable by replacing this valve.
Cheers
LuckyLes

Better off changing the compressor.
A lot of work to change the valve only to find it is the compressor afterwards,although you could be lucky.

[DiscoJeffster]

I changed the valve for only a minor improvement. Still haven’t got around to getting a new compressor

[haydent]

thanks id found the valves and wondered if my measurements might rule in or out a valve and or compressor.

[DiscoJeffster]

My layman view is that the compressor was commanded with the current representing the “position” of the command valve, yet no increase in pressure from baseline. I’d expect to see 1100 kpa when on. Also your evap temps don’t change. Definitely looks like a stuck valve, stuffed compressor.

Your baseline pressure is the same as mine ~116psi/750kpa.

I managed a capture on mine when it was blowing hot air once. Exactly the same output as yours. Everything commanded but no change. I switched the AC switch on and off, waited 5 seconds, turned it back on and then saw the pressure increase and evap temps drop. Eg flaky compressor.

BradC is your man for AC advice.

[haydent]

thanks, looking into compressor options now.

here is several posts about the gap tool readouts too starting here D4 A/C Compressor issue (https://www.aulro.com/afvb/l319-discovery-3-and-4-a/268239-d4-c-compressor-issue-5.html)

[Shannon]

Try a regas as step one. From there it’s the valve. Contact me for the part and order details

Hi there would you mind telling me the part and order details?
Thanks

[DiscoJeffster]

Hi there would you mind telling me the part and order details?
Thanks

This is the valve and where I purchased it from.

ELECTRONIC CONTROL VALVE FOR SANDEN PXC16, CVC14, CVC16 COMPRESSORS (https://www.polarbearinc.com/index.cfm?fuseaction=product.display&product_ID=7941)

EX 032

[rapserv]

Quoted me nearly $800 to change the AC compressor valve. Got the valve for $100 and will fit myself. I’ll factor in a couple of hundred to scavenge and refill the refrigerant to change the valve myself. Couldn’t justify that sort of money for a relatively simple task.

NOTHING is 'simple' when it comes to Land Rovers!![bighmmm]

[Tombie]

NOTHING is 'simple' when it comes to Land Rovers!![bighmmm]

You reckon?

Some of the easiest vehicles to maintain I've ever worked on.

The AC in the RRS went on the blink. I got the valve, got a set of extended circlip pliers.
Front wheel off, valve out (degassed before hand of course), new valve in, circlip back in, plug on.
Quick drive to mates workshop - Gassed up...

Chilled air [biggrin]


Try working on some of the other modern stuff - the LR is much easier in most cases.