Aircond functions fine, but no cold air

[titan 4380]

My AU1 airconditioning appears to be working just great, but doesn't blow cold air.
The compressor engages when the CC is switched on.
The lines leading into the cabin are cold and are often covered in frozen condensate
The vents initially output cold air, but this gradually becomes the temperature of the ambient air.
The fan is working fine and blows a gale when on full speed.

I tried to find answers on this forum, but most threads eventually end up as a squabble with very little solutions or ideas imparted. Any ideas?

[Citroënbender]

I’m sorry to hear you don’t like Scrabble.

When the cabin air reverts to ambient, what state are the refrigerant lines found in?

[titan 4380]

Originally Posted by Citroënbender

I’m sorry to hear you don’t like Scrabble.

When the cabin air reverts to ambient, what state are the refrigerant lines found in?

I do like scrabble, but I dont like squabbling . The frozen condensate has melted, but the lines are cold.

[lumen8]

I'd disconnect my heater hoses and go from there, if the lines are indeed cold enough to feel like they are refrigerating.

Eliminate causes.. since one cause could be a blend failure, hot water and hence air being present when it shouldnt be.

You can also actually create a small access hole behind the glovebox and stick a temp probe at or right next to the evaporator, you can visually see the evaporator if you make this hole in the right place. You would need to then plug that hole afterwards though.

[Citroënbender]

It is sounding like low gas. The pressostats are not very reliable in these, and will clutch on a compressor when service pressure really isn’t enough.

If it is outside limits when you put gauges on it, check the front shaft seal of the compressor for congealed oily leakage.

[lumen8]

Checking pressures should be the first thing to do yep. Not everyone has gauges though. They dont cost much these days. Plenty of charts online as to what pressures should be for given ambient temps.

The other thing is that the clutch could be disengaging and cant always tell or hear it. One way to know for sure, and ive done this on one of my cars, is put a small blue LED in the car that gets its juice from the compressor clutch circuit. When the blue light is on you know you are good, no guessing or trying to follow the sound of the clutch on and off when driving.

[XC50077]

My AU2 XR8 did this and also blew vapour from vents. A/C mechanic friend did a check over of system and then evacuation and regassed and was all good.Cheers

[PG2]

I had the same problem once and a very wise man told me that it would be the orifice tube. So I did what he told me to do and had it replaced. Air conditioning was then icy cold all of the time.

That wise man was Franco...

[titan 4380]

"orifice tube", now that is a rude word. Any idea where in the AC system this device resides?

[lumen8]

Originally Posted by titan 4380

"orifice tube", now that is a rude word. Any idea where in the AC system this device resides?

The AC pipe on the left hand side that runs parallel to the front guard.

You will see a couple of nuts there, it lives in there, separate the lines and you can remove it.

[titan 4380]

Originally Posted by lumen8

The AC pipe on the left hand side that runs parallel to the front guard.

You will see a couple of nuts there, it lives in there, separate the lines and you can remove it.

With my limited experience in domestic AC this device is called a "flash valve" as it is the point where the compressed liquid is flashed into a cold gas. I guess that cars use their own, unique terminology. Anyway, thanks for the tip as I will look into that. They are only about $19 on ebay plus a regas, so this might be a cheap fix. I checked out your car collection... very nice.

[lumen8]

Originally Posted by titan 4380

With my limited experience in domestic AC this device is called a "flash valve" as it is the point where the compressed liquid is flashed into a cold gas. I guess that cars use their own, unique terminology. Anyway, thanks for the tip as I will look into that. They are only about $19 on ebay plus a regas, so this might be a cheap fix. I checked out your car collection... very nice.

Thanks, and yes that is correct, it is where the action happens, you can feel the line gets cold after the orifice tube, the gas expands and things get cold as a result.

If you remove it and see its dirty/blocked, thats a good sign, it means it was an issue.

AU's have 'orifice tubes' but some vehicles have TX valves, two different ways of doing the same thing. So TX valve is another thing you will hear mentioned with car AC's.

[titan 4380]

Originally Posted by lumen8

Thanks, and yes that is correct, it is where the action happens, you can feel the line gets cold after the orifice tube, the gas expands and things get cold as a result.

If you remove it and see its dirty/blocked, thats a good sign, it means it was an issue.

AU's have 'orifice tubes' but some vehicles have TX valves, two different ways of doing the same thing. So TX valve is another thing you will hear mentioned with car AC's.

Yes!,the "TX valve" term was what was confusing me because I had heard it before and didnt realise that was the same thing as the "orifice tube". Got a question for you: what platform was your Fairlane built on? I am guessing the BA station wagon, but a mate of mine said it was a specific, unique design.

[lumen8]

Well the TX valve isnt the exact same thing as an orifice tube, it does a similar function, but it is two different ways of doing it. TX valves look like a block of metal with a temperature probe in them.

The AU/NU/DU fairlane when looking underneath is basically an AU falcon sedan with an extra piece added in the floorpan , including little chassis rail extensions. You can clearly see the extra bits added to the existing falcon floorpan and chassis pieces when you look at them both on a lift and compare.

Outside of this area, you will find it is identical underneath to an AU falcon, the front and rear of the chassis.

The wagons are different in the rear chassis rails, they are a different rear, although yes from the outside the rear doors and rear quarters on the wagon are basically fairlane. But the rear floorpan isnt.

The wagons have slightly different rear chassis rails, different fuel tank, different rear floor between the rails, the fairlanes (like the AU falcon sedan) have the spare wheel well shape in the boot floor... whereas the wagons floor is about 2 inches taller and flat, and the spare ratchets on from underneath similar to the utes.

So in summary id say the fairlanes are an extended AU falcon sedan, but with wagon rear doors and its own unique roof and C pillar.

[titan 4380]

Thanks for pointing out how little I know about locally produced cars. Looks like I only half won the argument with my mate
The moral of the story is dont argue about sh!t when you are not 100% sure.

[lumen8]

Originally Posted by titan 4380

Thanks for pointing out how little I know about locally produced cars. Looks like I only half won the argument with my mate
The moral of the story is dont argue about sh!t when you are not 100% sure.

To put it another way, you can put a base AU sedan non IRS rear in a fairlane without too much trouble and it will look factory... and vice versa.

You just need to install the correct brackets and pressings from the donor car, the biggest one being the stamped steel crossmember that the watts link bolts to. They will swap from one to the other when the spot welds are drilled out.

Cant say the same for the leaf spring wagon rear, youd be making custom rear mounts, have to re-jig/customize the fuel tank somehow, the list goes on... completely different rear floorpan on the wagons.