Citroen CX Air Cond Options

[Chatty]

Your opinions please? I have four options:

1) Get the original early a/c unit working with standard evaporator the size of a piece of toast wrapped in ice cream carton like housing!? Insulated it all like an Egyptian Mummy and fill in all the air gaps that are everywhere and just use it to just demist the screen OR

2) Plus add the rear a/c unit from my '78 wreck to help cool the cabin OR

3) Add a new under dash unit where the glove box is

4) Alternatively put the under dash unit in the boot a la Jaguar 420/Nissan President?

I will insulate the cabin. I have a Sanden R134a Compressor & late model Ford condenser to install. There are new Combined Heater/Evaporator units available on ePray for around $200.

Values of the CX don't dictate originality more so previous owner improvements it seems.

 

[DoubleChevron]

Whatever works for you. The evaporator isn't the issue so much as the lack of air flow through it. The main obstacles are the heat soak (can be overcome with insulation) .... then finally one major final one that I haven't fixed yet. You need ...... require and athermic windscreen. Quality tinting on the side windows helps massively.... To the point we used to travel windows up on 30+degree days in mine when it didn't have A/C as it was cooler than winding down the windows and getting baked by the sun.

seeya,
Shane L.

 

[robmac]

There are lots of previous threads on this very subject. Many dedicated to D series but equally applicable to the Cx.

 

[Chatty]

Thanks Gentlemen. I'll have to research the DS threads too. A good old fashioned windscreen visor and rear venetians with white wall tyres to add (A captain slow rat rod is the goal, it's certainly not a series II turbo)

I purchased a NC Fairlane evaporator on a whim remembering they had great a/c. It nearly fills the space between the cross bar and fire wall alone without the blower unit! No wonder Australian cars are best for our summers. The rear unit (in my '78 donor) also looks feeble in comparison to the unit my old Toyota Crown had. Or are they ok and worth installing?

 

[DoubleChevron]

I had a look. the thread I did on this must have been lost in the crash. I'm assuming by insulation you have seen this stuff ??

EZ Cool Automotive Insulation heat barrier and noise reduction for cars, trucks, classic cars, street rods and much more

I know some nutter in Australia that covered his CX and ID19 in that stuff

seeya,
Shane L.

 

[Rob T]

Jinandfonic,

I have a twin air set up in my 81 car and it works OK in Brisbane. Not as good as a modern car but definitely better than nothing. Mine is still working fine with Hychill and hasn't been touched since 2009.

The old threads really do seem to be gone. I have also searched and get nothing. Was it really that long ago....

The following text is the only part of the old CX thread that I have saved on my computer. I will also try and attach the photos again.

I have now got my aircon gassed up and running. This has been a long saga that started a few years ago. The original dual setup in my car was converted to R134a but it was never very good and would only work OK for a month or two. I had it 'fixed' at least 3 times but it never lasted - and nobody could identify the leaks. So I bit the bullet and tossed out all of the 'used' equipment. We fitted a new compressor, new parallel flow condenser (the largest that would fit in front of the radiator) and all new barrier hoses with O-ring fittings. At the time virtually nobody was aware of Hychill and even the one air con man I did find that did have it was still recommending going 134a. So all the components were for sized for 134a, except the existing evaporators. About 3/4 of the parts were fitted and then the project fell into a hole for a couple of years....I don't even remember why now.

Thanks go primarily to Shane for kicking it off again when he documented his efforts in his thread. More research into Hychill convinced me that it was both suitable and safe. You can buy it in small cans over the counter at Bursons, and you don't need a license like you do when dealing with R134a. This time I decided to finish it myself because it seemed to be the only way to get it done the way I wanted it. Not that I'm hard to get along with - it's just that the job has to be done right :wink2: Hychill is cheap, but I had to buy a crimping tool, vacuum pump and gauge set. I also had to get some more fittings, some small amount of copper pipe and a flaring tool. It took a while to find the distributors for a/c components because they don't advertise much, but there are lots around when you dig. I went to JAS Oceania. They are close to home and were willing to do small cash sales. Air con fittings turn out to be pretty cheap but there are a bewildering array of components available. I got most of my education from Heatcraft catalogues and other Australian sites like Speedy Air Spares and Scherbra (sorry, the forum is complaining about some of the links, you will have to look up the hard way - scherbragroup.com.au). By reading sites such as Vintage Air(vintageair.com) and AC Source (AC Source - Automotive Air Conditioning, AC Parts Tools Equipment Kits) who also have a good forum and DIY articles. I bought the crimping tool via eBay from Mechanix Gear (International Shipping, ATD items in Mechanix Gear store on eBay!) in the USA because it was about 1/3rd of the local price. Very competitive pricing even by eBay standards and cheap shipping. And I bought cheap Chinese gauges and vacuum pump from an Australian eBay seller tritrade (My World) who is an A/C mechanic and said all the right things in his ad. Again, very happy to recommend him.

Anyway, there are a few pics attached, mainly of the rear evaporator. I also had to fix the belt tensioner. The bearing was cactus and I couldn't track down one of the original INA needle roller types - except from CX-Basis who list them at pretty big prices. So I bought an idler that uses a standard ball bearing at the local CBC and got my friendly machinist to make up a shaft that we welded back into the original mounting plate. He owes me a few favours, so did it for nix. But it is a simple job for anyone with a lathe.

I modified the rear evaporator housing so that cabin air is returned to the unit via the left hand vent. I don't think that there is much return air coming in under the seat, since the seat effectively blocks the holes. This means that there is probably a lot of recirculation within the unit. All it took was a divider (glossy black paint in the pics) and a few holes in the end of the box section. I did it this way so that I could easily rivet cover plates back on if it didn't work. I could have just cut the end of the box section off. I used a pinchweld rubber seal from Clark Rubber for the box section to underside of parcel shelf gap. It works well and comfortably accommodates the un-even pressed shelf surface. I also payed attention to the sealing of the rear cover board. And it all works. The boot is no longer the coolest place to travel in the CX.

I added a thermostat and solenoid valve to the rear evap and I fitted copper pipe extensions to the TX valve so that the hose connections were accessible. The rear thermostat had only a short tail so I mounted it in the side of the housing. The temp control is only accessible from the boot. If I was doing this again now, I would be looking for an electronic thermostat and mount it with the fan speed switch on the rear end of centre console. I suspect that the front thermostat doesn't work right - so it might get replaced with an electronic one soon. Another 'one day' job. Even the condensate drains actually work. I cleaned all the dirt out of the plastic pipe and I have actually seen water running down them - enough to leave a puddle on the floor.

Despite due care and attention, I was convinced that I would have a leak since there are so many joints and connections in the system. So I vacuumed it down and let it sit for about 4 hours. Much to my surprise, the gauges stayed where they were supposed to. I put 460 g of Hychill in. The low side gauge was still a little low, but given Shanes experience I elected to go with it. 460 g of gas is already a little bit more than was listed for most twin systems such as the Tarago's. Anyway, a week later the gauges have settled down into an almost perfect 30 / 150 psi low / high side.

Performance has been pretty good. It was cool and overcast last week and the car would readily get too cold. It's been much hotter this week. The system copes pretty well, definitely much better than having the windows down, but not as good as modern Aussie cars. It doesn't take much sitting in traffic before the high speed fans cut in, and the engine temp hovers around the 92 degree point a lot. My car is fitted with the vacuum operated valve that lifts the idle speed when the a/c is running. I have adjusted it to idle at about 1200 rpm. This is still too slow for the compressor to keep up with demand - and it is a bit too fast when driving in traffic. Engine braking is noticeably less.

I have hooked one of those cheap indoor / outdoor thermometers on the vent. You can see it in one of the photos. Air temp is often down to 18 inside. The outside sender sits just in the top of the vent tower and is out of direct sunlight. It typically shows temps of around 45 degrees when the car is stationary. The vent tower is well sealed and insulated with a 10 mm aluminium faced closed cell foam. So I guess the outside temp is indicative of how much heat the air picks up as it gets drawn in across the bonnet. It would be interesting to see what the air temp is like just ahead of the a/c evaporator - that would tell us how much heat is picked up on the way thru the duct. I will try to relocate the temp sensor one day. Anyway, it seems that I am getting the best part of 30 deg drop in air temp - and that is a bout all that Hychill is capable off.

There is still plenty of heat coming in thru the windscreen. The dash gets pretty hot - I would guess in the range of 50 degrees. Stopping the heat coming thru the glass would make a considerable difference to occupant comfort....

And the other real problem is the inadequate fan / vent system. It is simply not capable of delivering sufficient quantity of air directed to your face. I don't think there is any simple solution to this one.

Anyway, given that the CX had a reputation for poor ventilation even when new, I'm pretty happy with the result. Not as good as a modern car, but it sure makes the car more liveable in this hot and humid climate.

Now that I have the tools, I am willing to help others sort out their aircon problems. Fittings and hose are cheap. Hychill is cheap. Your own labour is 'free'. I'd hate to see the tools sitting around unused...​

I still have the tools and you are welcome to come and see my car.

 

[JohnW]

I had a look. the thread I did on this must have been lost in the crash. I'm assuming by insulation you have seen this stuff ??

EZ Cool Automotive Insulation heat barrier and noise reduction for cars, trucks, classic cars, street rods and much more

I know some nutter in Australia that covered his CX and ID19 in that stuff

seeya,
Shane L.

He must have been crazy.

 

[JohnW]

Whatever works for you. The evaporator isn't the issue so much as the lack of air flow through it. The main obstacles are the heat soak (can be overcome with insulation) .... then finally one major final one that I haven't fixed yet. You need ...... require and athermic windscreen. Quality tinting on the side windows helps massively.... To the point we used to travel windows up on 30+degree days in mine when it didn't have A/C as it was cooler than winding down the windows and getting baked by the sun.

seeya,
Shane L.

So, again, is there enough interest out there to get some athermic windscreens?

 

[DoubleChevron]

So, again, is there enough interest out there to get some athermic windscreens?

Lots of interest, little $$$$

 

[JAJEA]

Do you have a choice for a DS 23 windscreen (not greatly concerned with affect on GPS's)?

John

 

[Chatty]

Wow that is a very thorough overview Rob T, Many thanks for sharing.

Seeing & reading the expertise required that I currently lack, It seems best to take the easiest option of an under-dash unit mounted in the glove box. At least it will be within the confines of the cabin recirculating the air more efficiently than through the engine bay arrangement. If I can still incorporate the standard evaporator to assist & ensure proper de-misting I will.


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[Chatty]

So, again, is there enough interest out there to get some athermic windscreens?

What is required to get this underway? My C4 has it & it works well. The down side is my C4's mostly black glass roof which works like a solar panel in summer. Car is otherwise white. I made a double windscreen reflector mat that fits between the blind & the glass which helps greatly. Any car with this option really requires the dual a/c units. I saw a 407 wagon with a huge glass roof, what a sauna! If next summer is any hotter, out will come the white paint & brush! Otherwise it's a great option at night & during winter.


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[Greg C]

Andrew, I note you have a trinary switch on your receiver dryer, have you got that wired across the thermal switch so high head pressure can get the fans to high speed. Or is it that Hi Chill does not generate such high head pressures.

That said my twin system with factory rear unit on R134a works quite well 95% of the time. The main thing it needs is a solenoid valve and thermostat on the rear unit to stop rear passengers freezing

I would put my hand up for an athermic windscreen if one was available

 

[meinkiev]

I had a look. the thread I did on this must have been lost in the crash. I'm assuming by insulation you have seen this stuff ??

EZ Cool Automotive Insulation heat barrier and noise reduction for cars, trucks, classic cars, street rods and much more

I know some nutter in Australia that covered his CX and ID19 in that stuff

seeya,
Shane L.

Shane, I had a look at that nutter's insulation work, and as crazy as he must be, it is quite impressive! I want to do similar, so can you tell me how much of that stuff I will need to do my CX? I may use double on the floor and lower sections, I will do the boot and bonnet, and the air intake and engine side fire-wall, and the air-con evaporator box, and bits and pieces, etc. My roof lining is in good shape, so I will leave it for now, but lets include it too. How much will suffice?

I presume the glue is readily available in Oz? What are the brand names?

I will probably want more later to do a DS or something, but if the postage is for each roll, then it can wait probably.

I can probably tint the side windows if you think this helps a lot? How much do these athermic windscreens cost? Do they have to be specially ordered, and in numbers?

Also, can you tell me how you modified the air-con evaporator to seal it and get more air-flow through it? Can a more powerful fan be fitted to get better air-flow? What other mods did you do?

I will try all this before I decide to add another system to the single one I have. I have done this all before for a badly insulated and air-con'd John Deere tractor cabin that was operating in extreme heat all harvest, so I know sealing and insulating is the place to start.

 

[IE23]

Good window tinting is the best thing to do, without it you will never beat solar radiation no matter how good the AC is. I'm not a fan of dark windows but the improvement you gain in heat and glare reduction far outweighs the presentation concern. I chose the lightest colour possible so as to not look like a pimp mobile.

 

[DoubleChevron]

The windscreen bit ... it can be done. I'll never in the distant future I that I can see have that sort of money to spend on a windscreen though... If the one in mine broke, I'd find the cheapest possible screen available to get the car on the road again.

Window tinting makes the biggest difference of all. To the point where we used to travel windows up in a CX on 30+degree days If you insulated a CX, put the tinting in and had an athermic windscreen, you would have the battle won. The bog standard A/C without upgrades would probably be effective for the majority of weather.

I bought in 200square feet of that insulation. You'll find you can use it everywhere.

seeya,
Shane L.

 

[Greg C]

One of the biggest improvements you can make to the standard system is fit a trinary switch on the receiver dryer. It is then easy to wire the high head pressure contacts across the thermal switch on the radiator. On warm days it gets the front fans to high speed almost straight away. BXs were the first Citroen to get these but all modern cars have them or something similar.

 

[meinkiev]

Thanks for the advice fellas. I will start with insulation, then tinting (I don't like my car looking like a Russian mafia job either Adrian, so it will be as light as possible), and I will look into the trinary switch on the receiver drier as well, Greg. I already have a rear external louvre which has to help a lot as well.

Thanks Shane, I will order the insulation now, so I can start when I get home.

What about the Hychill? how important is that?

Looks like my CX will be almost permanently off the road getting things done to it!! So perhaps the XM will get a bit of a run for a while.

 

[Chatty]

Has anyone put in a heater tap or found by disconnecting the heater it improves the CX front unit cooling? Except for the early CX I's (2200) which have a tap the later series I's (2400) have a flap to a separate heater box (with old seals now) I can imagine a heater that is always on within the system would generate extra heat soak?

 

[DoubleChevron]

Has anyone put in a heater tap or found by disconnecting the heater it improves the CX front unit cooling? Except for the early CX I's (2200) which have a tap the later series I's (2400) have a flap to a separate heater box (with old seals now) I can imagine a heater that is always on within the system would generate extra heat soak?

I found it made a difference.... That being the heater no longer worked in winter. Sure was still bloody hot in summer though!!

Seeya
Shane L



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