A/C Not Working

[Ralph1Malph]

Hi All,
My A/C has stopped working all of a sudden. And I mean all of a sudden!
Cold Cold Cold not Cold!

I searched and read about a few things that cause this but thought I'd seek advice.

Obviously it could be low gas. I recently had the radiator and intercooler replaced, which necessitated removing the condenser and emptying the system.
I would have thought that a leak would have the effect of reduced efficiency over time.

Before I look into the compressor side of it, I was looking for an A/C fuse or relay, but I'm either a dummy or a there isn't one!

I do have a HSE so it has rear A/C which I believe is a second evap but still only one compressor

I put my Gap tool on and got the following results:
System pressure 787.5kPa; Compressor /motor current 212A; Evap temp 37.0 although did reduce marginally over a few minutes; Ext ambient 32.5.

I'm not sure what to think about the compressor current, that's stupid high, but maybe it's a gap tool thing.

Thoughts, suggestions?

Ralph

[4bee]

Is possible the Electro Magnetic Clutch has failed therefore while it is spinning, it may not be actually driving the Compressor. Wiring fault or blown fuse or a failed Clutch.

NB. I am assuming the HSE has such a clutch assembly.

No idea why you are getting partial operation unless the cause is intermittent.

[scarry]

I don't think the gas is gone at that standing pressure,if its correct.

Unfortunately,the compresser could be shagged,not pumping,to stop suddenly,or an electrical fault thats stopping the compresser.

There is an unloader valve that goes in them sometimes,but doesn't sound like yours has those symptoms,and my Indie told me they generally fail in the later 3.0L D4.

[PerthDisco]

UK cars the under car pipe work corrodes to rear AC and causes fail.

[DiscoJeffster]

Hi All,
My A/C has stopped working all of a sudden. And I mean all of a sudden!
Cold Cold Cold not Cold!

I searched and read about a few things that cause this but thought I'd seek advice.

Obviously it could be low gas. I recently had the radiator and intercooler replaced, which necessitated removing the condenser and emptying the system.
I would have thought that a leak would have the effect of reduced efficiency over time.

Before I look into the compressor side of it, I was looking for an A/C fuse or relay, but I'm either a dummy or a there isn't one!

I do have a HSE so it has rear A/C which I believe is a second evap but still only one compressor

I put my Gap tool on and got the following results:
System pressure 787.5kPa; Compressor /motor current 212A; Evap temp 37.0 although did reduce marginally over a few minutes; Ext ambient 32.5.

I'm not sure what to think about the compressor current, that's stupid high, but maybe it's a gap tool thing.

Thoughts, suggestions?

Ralph

There is no clutch. It’s a displacement compressor so a valve varies the output rather than a binary on/off of a clutch.

[BradC]

I'm not sure what to think about the compressor current, that's stupid high, but maybe it's a gap tool thing.

From what I've been able to ascertain the "compressor current" seems to be a vague interpretation of the displacement valve duty cycle. On mine about ~235 is flat out and it comes back to ~100 at lower loads.

Your pressure matches your evap temp pretty much on the nose and the pressure is measured high side. Likely the displacement valve is jammed shut or the compressor is toast.

[4bee]

There is no clutch. It’s a displacement compressor so a valve varies the output rather than a binary on/off of a clutch.


Thanks DJ, I am not familiar with this noo fangled stuff, but one lives & learns. [smilebigeye]

[jwb]

I had poor and intermittent cooling on mine. Re-gas didn't fix, although gas was down a bit.
Compressor replaced and running cold now. I was surprised at how bad it had become when it came back to normal.
Happily done under extended warranty.

[Ralph1Malph]

From what I've been able to ascertain the "compressor current" seems to be a vague interpretation of the displacement valve duty cycle. On mine about ~235 is flat out and it comes back to ~100 at lower loads.

Your pressure matches your evap temp pretty much on the nose and the pressure is measured high side. Likely the displacement valve is jammed shut or the compressor is toast.

Thanks! Just as a matter of interest, is it 'easy' to replace a compressor?
I know it won't be, but I do have one lying around and would be great if I could do it on a weekend!
I have read that the displacement valve can be replaced as well. I better look into it!

Ralph

[josh.huber]

There is no clutch. It’s a displacement compressor so a valve varies the output rather than a binary on/off of a clutch.
I'm pretty sure that's incorrect, but I will double check for you. Yes they have a valve to vary displacement or flow, but I'm 99.9% sure there is still a clutch on the front. The high low switch will generally control this and the ECM will control the displacement due to cooling requirements

[DiscoJeffster]

I'm pretty sure that's incorrect, but I will double check for you. Yes they have a valve to vary displacement or flow, but I'm 99.9% sure there is still a clutch on the front. The high low switch will generally control this and the ECM will control the displacement due to cooling requirements

I don’t need you to check for me lol. There are only two wires that go to it which go the the displacement valve. FYI it’s a Sanden PXE16 compressor. Go and take a look for yourself.

[BradC]

Thanks! Just as a matter of interest, is it 'easy' to replace a compressor?
I know it won't be, but I do have one lying around and would be great if I could do it on a weekend!
I have read that the displacement valve can be replaced as well. I better look into it!

"Easy" is relative.


Remove gas
Disconnect and plug pipework
Remove compressor
Fit new compressor
Reconnect pipework
Vacuum system to remove moisture
Pressure/Leak test system
Vacuum system to remove pressure testing gas
Replace Gas


Because it's a continuously running compressor (even at minimum displacement) you don't want it running with no refrigerant as it'll just pump the oil out. So it all really needs to be done from end to end without starting the car.

If you know someone with a recovery machine, gauge set, vacuum pump, high pressure nitrogen bottle/reg and ideally a vacstat then it's doable.

[DiscoJeffster]

Not to mention it’s a ***** to get to and remove and install. Even with the body off it’s buried in there.

[Ralph1Malph]

Not to mention it’s a ***** to get to and remove and install. Even with the body off it’s buried in there.
Now we're talking!
That's the bit I'm after. [bigsmile]

[scarry]

"Easy" is relative.


Remove gas
Disconnect and plug pipework
Remove compressor
Fit new compressor
Reconnect pipework
Vacuum system to remove moisture
Pressure/Leak test system
Vacuum system to remove pressure testing gas
Replace Gas


Because it's a continuously running compressor (even at minimum displacement) you don't want it running with no refrigerant as it'll just pump the oil out. So it all really needs to be done from end to end without starting the car.

If you know someone with a recovery machine, gauge set, vacuum pump, high pressure nitrogen bottle/reg and ideally a vacstat then it's doable.

And replace drier,if there is one.

[PerthDisco]

Now we're talking!
That's the bit I'm after. [bigsmile]

When doing the coolant change in a pit with all underbody engine covers off recently I noticed great access up to the alternator from underneath. Potentially a better way to get at the AC pump.

[josh.huber]

I don’t need you to check for me lol. There are only two wires that go to it which go the the displacement valve. FYI it’s a Sanden PXE16 compressor. Go and take a look for yourself.

Yeah I checked earlier, we must have different builds or compressors. Mine definately has a clutch and a variable displacement solenoid.
MY11 SDV6 over here

[Bendys]

My TDV6 2010 H4 HSE with rear air con also stopped working. It does have a clutch on the front. Its a hybrid compressor with clutch AND variable stroke, with the control valve at the rear of the compressor.
The compressor was spinning with air con on, but no cold air. Pressure test & no gas has leaked.
Service manual states clutch is safety measure if compressor seizes.
There is a service bulletin LTB00693NAS1 regarding this.
I had my system de-gassed, valve replaced with new (disassembled old valve & ill post picks soonish), refrigerant oil replaced (to reduce re-contamination) leak tested & re-gassed. So far so good, but was $900 later.

[Ralph1Malph]

Well, I finally got around to having this fixed.

Luckily for my wallet is wasn't the compressor.
It turns out the rear evaporator was leaking.
To replace the rear evaporator is expensive and time consuming so I decided have a custom pipe built that bypasses the rear evap.
Seeing as I have removed seats 6&7 and fitted a false floor and fridge slide, I reckon it'll be ok and seems to be a common compromise.
Interestingly, the Indy that did the work, said that it's becoming more and more common for the evaps in older high km D3 to leak.
This is consistent with other brands I've owned and research I've done. The chemical composition of the refrigerant and lubricants simply makes the thin walled evaporators porous over time.

Cheers
Ralph

[scarry]

The chemical composition of the refrigerant and lubricants simply makes the thin walled evaporators porous over time.

Cheers
Ralph

Generally, thats only a very rare issue,caused by acid and contaminants in the system,which wouldn't be common in an auto system.

Particularly if it has never been worked on,and also sealed since new.

If so, it needs a very good clean up or the new evaporater will not last long.

Generally evaporators leak due to corrosion on the external surfaces,common issue,leaking from an internal issue is very rare..

[Ralph1Malph]

Generally, thats only a very rare issue,caused by acid and contaminants in the system,which wouldn't be common in an auto system.

Particularly if it has never been worked on,and also sealed since new.

If so, it needs a very good clean up or the new evaporater will not last long.

Generally evaporators leak due to corrosion on the external surfaces,common issue,leaking from an internal issue is very rare..

Well there you go! Thanks for adding and clarifying that Scarry as I was convinced it was the additives in gas and comp oil. I guess either way I reckon I got out of it fairly lightly!
Interestingly, I had to replace my D2 evap about 5 years ago and I wish I'd taken some pics as the dye made the evap look like swiss cheese lol.
At less than $1000 I am just chuffed I can roll the windows back up!

Cheers
Ralph

[PerthDisco]

Yep I’ve not read to date of anyone pulling the dash apart to get the main evaporator out. It is a secret fear as I’ve had cars previously where the AC has failed and you’re then in window down mode just like the ‘good ol’ days kids’ but to be honest it absolutely sucks having no AC.

[scarry]

Well there you go! Thanks for adding and clarifying that Scarry as I was convinced it was the additives in gas and comp oil. I guess either way I reckon I got out of it fairly lightly!
Interestingly, I had to replace my D2 evap about 5 years ago and I wish I'd taken some pics as the dye made the evap look like swiss cheese lol.
At less than $1000 I am just chuffed I can roll the windows back up!

Cheers
Ralph

Yes,in commercial refrigeration we see the swiss cheese effect all day.Around 99.9% are copper,where auto are generally aluminium.
The copper is as thin as a piece of paper.Its not only corrosion,mainly from food acid,but it also comes from the glue on the boxes in bottle shop cold rooms,and other things.Split tubes,leaking joints, are also an issue.
We generally replace two to three evaporator coils each week.
We try to use evaporators that have a corrosion protection coating,where we can.

Thats out of around 650 cold /freezer rooms we service,and about 300 refrigerated cabinets,at least.

Everything is just built cheap,30yrs ago,we wouldn't have changed more than 10 evaporators a year.
The evaps today weigh less than half what they did 30yrs ago.

All this cheap garbage just increases the release of refrigerants into the atmosphere.[bigsad]
But thats another story.[biggrin]