|VOLVO 240 AC PAGE
And Classic Auto Air AC Installation Project
|UPDATED: October 11, 2023 CONTACT|
O M A I N S
|240 Original AC INTRO
||Stock 1991 and LATER 240 AC
||240 AC Systems Overview
|Later 240 AC Wiring Diagram
||Using PROPANE (R290) in your AC
||DURACOOL R12 Replacement
|First Classic Auto Air
Installation in a 240 (2016)
|Classic Auto Air
Installation Starts HERE (2017)
|Classic Auto Air
vs Vintage Air
|New Larger AC Ducts Installed (2021)
||AC Hose Assembly
Traditional Crimp and Other Alternatives
|Dash Wiring Basics
|RESULTS: 134A vs Duracool
||AC Too COLD?
Preventing Evaporator FREEZE-UPS
|Evap Temp Controller
for Precise Temp Control
|Before completing my new AC system installation, I first gutted the interior and installed DYNAMAT.
CLICK HERE to see the 240 DYNAMAT Installation Page
If you have any suggestions to improve the information in this page, please email. Thanks, Dave
enjoy taking long road trips. Taking a long road trip in a hot car in
hot climate is not as much fun. So when I take a long road
trip, how much better would it be if I had decent AC?
Getting satisfactory AC in an early 240 can be a real challenge. I sincerely believe the AC systems in these cars were designed with only northern European climate in mind.
They were almost always a disappointment for U.S. owners in warm weather. In older 240s ( pre-1991) the AC systems were just not up to the task.
Volvo didn't really try hard at first for a great result. The 1984 Volvo 240 factory specifications called for AC output temperature from the center vents to be 48-54 degrees Fahrenheit.
The AC was later improved for 1991-93 cars when a differently design system was used.
Image below shows a pre-1991 240 AC, showing an AC drier on the right fender.
|So then is LATER 240 AC BETTER?
The answer is YES!
Thermal Expansion Valve versus Orifice Tube.
Later 240s made from 1991 to 1993 got a more modern system that can be recognized by the big silver aluminum accumulator/drier near the right side firewall. These systems were a different design. These later systems incorporated an ORIFICE TUBE rather than a THERMAL EXPANSION VALVE (TXV) found in older systems.
The 1991-93 system began using an Orifice Tube instead of a TXV, but retained R12 refrigerant through 1992. The 1993 models were changed to use the new R134a.
Image below of 1991-93 240 AC (showing larger accumulator/drier near firewall).
Late 240 AC Components
Here's an overall image of the entire 240 AC system along with a later style AC evaporator box, accumulator, compressor and condenser.
1985 versus 1993 Evaporator Box Comparison
The above image shows a side by side comparison of a 1985 (on left) and 1993 (on right) evaporator box. This view is of the bottom, showing the vacuum reservoir used for vent control functions.
The boxes are slightly different in a few measurements, but ultimately can be interchanged if you're up to the challenge of such deep dash disassembly.
Evaporator Coil Design Changes for 1991.
The 1991 and later 240 evaporator box under the dash was a different design and it used a more efficient evaporator coil inside.
The first photo above shows the old style copper TUBE AND FIN design. The second photo above is the more efficient and larger aluminum parallel flow coil design, which was used in 1991-93 240s.
240 AC hoses, couplings and fittings have always been standard SAE thread components. It has been reported that for 1993 ONLY, the accumulator on the firewall received METRIC THREAD fittings.
More general information about 240 AC systems can be found in the next section below.
FRONT CONDENSER INFO
I have some useful info on ORIGINAL versus NEWER style condensers in my CONDENSER SECTION further down in my page.
|Introduction of the Orifice Tube in the 1991 240
Here's a photo of a 240 ORIFICE TUBE being removed.
An orifice tube or orifice valve is a restrictive valve which is meant to force the pressurized refrigerant to expand after it passes the restriction. The expansion of compressed refrigerant creates the cooling effect in the evaporator coil. An orifice valve is generally a metal tube with a chamfered inlet and with a plastic valve body. It can become clogged or gummed up if debris or contaminates get into the system, especially if it was not in use or left open to elements or in the case of a compressor failure. This valve can easily be replaced if it's questionable.
This photo above is from the following thread on converting an early 240 to a later AC system: https://forums.turbobricks.com/showthread.php?t=357795.
|USEFUL 240 AC PART NUMBERS
1395590, 3513066 Compressor 240 to up 1992 R12.
6841028 Compressor 240 1993 R134a.
1370235 Accumulator/Drier 240 1990 R12 (RHD, LHD).
9144329 (1388667) Accumulator 240 1991-92 R12 (LHD-USA).
3540009 Accumulator 240 1991-92 R12 (RHD).
3540588 Accumulator 240 1993 R134a (RHD).
9131972 Accumulator 240 1993 R134a (LHD-USA).
3537866 Low Pressure Switch (pressostat) 1991-92 240 R12.
3537506 Low Pressure Switch (pressostat) 1993 240 R134a.
3522250 Thermal Expansion Valve (TXV) 240 1990.
1324829 Orifice Tube Insert 240 1991-92 R12.
3545086 Orifice Tube Insert 240 1993 R134a.
1214851 Evaporator Coil 240 to 1990 R12 (RHD, LHD).
3540231 Evaporator Coil 240 1991-93 R12 or R134a (LHD).
3522858 Evaporator Coil 240 1991-93 R12 or R134a (RHD).
1259556 Condenser before 1991.
3540373 Condenser 1992 R12.
3540647 Condenser 1993 R134a.
3540227 Condenser Fan Pressure Sensor/Switch 1991 R12.
6848106 Condenser Fan Pressure Sensor/Switch 1992 R12.
3540657 Condenser Fan Pressure Sensor/Switch 1993 R134a.
|Can I convert my old 240 to have later, more modern AC?
Yes you can. For those of you looking to convert an earlier pre-1991 240 to use 1991 or later AC components, here are some very useful discussion threads on this topic:
CLICK HERE to see a comprehensive WIRING DIAGRAM for later 240 AC BELOW.
SAE or METRIC HOSE FITTINGS?
All 240s used SAE fittings in their AC systems (with one exception). So this means that if you're repairing or making any new hoses, you'll usually need fittings with standard or SAE thread, not metric.
The ONE exception is the 1993 (one year only) 240, which reportedly used an accumulator/drier with metric threaded fittings.
|240 Vent Control Diagram for Vacuum Lines 1981-93 240 (USA).
I created the below diagram because nothing like it exists anywhere in any Volvo Greenbook and many people needed to know where all those vacuum hoses in your dash go.
For more vacuum diagrams, go to my Vacuum Diagram Page
Here's a comprehensive WIRING DIAGRAM I created for the 1991-93 240 AC system.
CLICK the BELOW IMAGE for a larger photo.
Or click here for PDF version you can print or download (800 kb): https://www.davebarton.com/pdf/240-1993-AC-diagram.pdf
Here's an alternate MODIFIED diagram below of the condenser fan for a LATER 240 fan circuit.
Normally the condenser fan only comes on then the Pressure Sensor is closed. Who wants that?
This modification diagram below changes TWO wires on the fan relay (see the blue boxes below) to allow the fan to run anytime the AC Compressor circuit is activated.
|R12 and R134a Refrigerants
R12 refrigerant was used in all Volvo 240s through 1992. Beginning in 1993 all 240s changed to R134a.
As previously mentioned, R12 was eventually banned in the U.S. and other developed countries in 1996 and then worldwide in 2010.
R12 is dichlorodifluoromethane, a colorless gas sold under the brand name Freon, Freon-12 or R12. It's classified as a chlorofluorocarbon (CFC). This CFC part is why it was banned because it potentially could damage the Ozone layer..
Thermal Expansion Valves were used in all 240 R12 systems up through 1990.
It is commonly believed that thermal expansion valves (TXVs) used in these cars were specifically adjusted by the factory (or by the TXV manufacturer) for use with R12. Then later when one of these 240s got retro-fitted with R134a, it would get a replacement valve that was supposedly calibrated for R134a. This raises questions about us DIY mechanics doing their own AC adjustments. Can we adjust a TVXs to suit R12, R134a or another suitable refrigerant. The answer has never come for certain.
This adjustment method on a TXV used in a Volvo is illustrated above.
With the TXV inlet port disconnected, an Allen (socket) wrench is inserted into the inlet port. There's a socket set screw with a spring behind it. That screw is is turned to adjust.
There are many opinions on what these adjustments need to be for different refrigerants and so far NONE of it is definitive.
A discussion thread on setting these valves is posted below. Some people claim to know the answers about this stuff, but I'm convinced no one knows SHIT.
TXV Adjusting thread: https://www.forums.turbobricks.com/showthread.php?t=213526
USING PROPANE AS A REFRIGERANT.
(Hydro-Carbon Refrigerant MIX)
In 2012 gave up on straight propane and began trying Duracool 12a replacement http://www.duracool.com/.
I later learned that Duracool is a mixture of Propane (R290) and Butane (R600). The precise mixture is not known by me and it's probably kept secret by Duracool. The addition of Butane in the mix seems to be the ultimate key in making it more consistent than propane alone. My introduction to Duracool was many years before I changed to Classic Air AC and I spent a lot of experimental time trying to get it dialed in. I tried a number of different thermal 240 expansion valves and a LARGE number of different expansion valve settings. My 240 eventually got pretty good cooling on the highway, but I still found intermittent problems at idle (although it seemed to get a little better than with just propane). I kept experimenting over the years with many different expansion valves and a huge variety of TXV settings, hoping to find the right combination that worked. Things never got great and ultimately I remained less than satisfied with my AC.
CLICK HERE TO SEE MORE ABOUT PRESENT DAY DURACOOL PERFORMANCE
AND MY ULTIMATE RESULTS WITH CLASSIC AUTO AIR.
IMPORTANT NOTE FOR 2023:
It appears the availability of R12 SUBSTITUTE refrigerants in the USA is being threatened by the US EPA.
In 2023 I began noticing that some R12 substitute companies, such as Enviro-Safe, have REMOVED all hydrocarbon (HC) R12 substitutes from their web pages. Some pages have mentioned this is the result of new US EPA SNAP regulations that became effective in May 2023.
Here's the EPA bulletin: https://www.epa.gov/snap/unacceptable-substitute-refrigerants
Here's more about what is considered an R12 substitute (HC-12a): HC-12a Wikipedia
So what can an amateur DIY AC tech do?
You can do plenty. I've already begun some experiments of my own with mixing my own Butane-Propane formula. If you begin your AC charging with Butane, you'll notice it will cool, but the reduction in temperature will be slower. Then when you begin adding Propane, that reduction in temperature speeds up rapidly. So increasing the percentage of Propane makes it COLDER. Just plan ahead so in the end you don't overcharge your system. If you goof, you can start over. A good chart to use to understand how much total Butane/Propane mix to use is the Duracool chart HERE. For example, my system is designed for 24 ounces of R134a. The Duracool equivalent is about 9 to 10 ounces total.
I use a digital scale to weigh a canister as efrigerant is being charged into the system, so I can see ounce by ounce precisely how much is going in..
Keep in mind that I've read some opinions that say some Propane available for automotive fuel may already have a percentage of Butane already in it. I don't know how you can test for or avoid that. The prevailing opinion for the typical 1 lb. Propane canisters you find at a store is that those are usually fairly pure Propane, but maybe not the purest you can get.
The ultimate goal for cold AC is to get an evaporator temperature as cold as possible, but to stay above 32°F (0°C) to avoid freeze-ups. If you cannot find a way to measure your evaporator temperature, then measuring vent temperature will be the next best thing, but read here for how I measure and regulate my evaporator temperature. Charging an auto AC system yourself and mixing two different chemicals is not difficult if you can competently use an AC charge hose and a postal scale.
If you search for information, you'll find a lot of opinions. Some will tell you that you must INVERT a Propane can when charging and install it as a LIQUID or the AC won't cool. I think this is B.S.
Inverting a can and charging as a LIQUID is recommended for refrigerant MIXES, such as Duracool, or any refrigerant that is made up of two or more chemicals. This is so the mix stays in MIXED FORM as it's installed. There's a concern with some mixes that if you install it as a GAS the mix might be uneven. Propane is a single component chemical and not a mix, so installing upright as a gas is ok. If you don't believe me, get two Propane cans and allow one to empty while upright. Allow the other to empty while inverted. Are they both equally empty? Did the inverted can empty the Propane in any better way? Maybe it was faster, but there's no difference.
Choosing Ordinary Propane or R290?
Should you buy cheap Propane fuel or more expensive R290? What about Butane or R600 (iso-Butane)?
If you decide to buy R290 you should expect it to be a more PURE form of propane than normal propane. R290 is refined specifically for refrigeration use. It will have less moisture content and it has no gas odorant added.
Buying R290 or R600 will be more expensive, but it should be better stuff as long as you buy from a reputable source. How much better is something I can't say. Enviro-Safe offers cans of refrigerant grade R290 and R600a (Iso-Butane).
Important criteria for R290:
Minimum Grade 2.5 (99.5% pure). Water content, <10 ppm water in the liquid phase. The use of the product name R290 followed by U.L. Classified indicates Underwriter
Laboratories has tested and evaluated samples of a product with respect to certain properties.
Always refer to the product Safety Data Sheet for more specific information.
|If you have done your own Volvo AC
upgrades or if you're planning to
do something like this, please email
me. I'd like to hear about
Also, if you have any suggestions to improve the information in this page, please email. Thanks, Dave
|DIY AUTO AC SERVICE
If you're learning about testing or charging your AC system, here's a pretty good video that will help with the basics.
AIR installed in a 240.
First came Michael Yount's 240 Installation.
This is what began changing me from a skeptic to a believer that real AC in a 240 was possible.
As you can see here, the old original 240 slide controls and vacuum push buttons are gone.
In their place is a new electronic control panel with knobs. It has fan speed, vent selection (front vents, upper defrost, and lower heat) and a cold/warm temp knob.
Try not to be confused when you browse Classic Auto Air's web pages. They also show setups using CABLE controls, but they don't explain very well why they show both setups. Basically the cable controls they offer are designed for classic cars where the owner wants to retain the original look of vintage cable controls.
|Before completing my new AC system installation, I first gutted the interior and installed DYNAMAT.
CLICK HERE for the 240 DYNAMAT Installation Page
If you have any suggestions to improve the information in this page, please email. Thanks, Dave
|Introduction to the Street Rod Cooler III
There were not many photos of this unit in their site, so I have included some here.
The above photo is from Aris (from Greece) taken during his 240 build, which can be found in his thread here: http://forums.turbobricks.com/showthread.php?t=310632
The above photo shows the original black 1985 240 condenser, which is made from TUBE and FIN construction. All 240s up through 1990 received a black condenser similar to this. The original size was about 15.5 x 26 inches.
Aris then fitted a new 16 x 24 inch universal PARALLEL FLOW CONDENSER, also shown above.
TAKE NOTE that the hose fitting sizes for IN versus OUT on a condenser are not the same size. The top one is larger (#8 male) and is connected to the hose going to the compressor. The bottom fitting is smaller (#6 male) and is connected to the hose to the drier canister on the right fender. I have more info about AC hose sizes further down in my AC build or CLICK HERE.
If you're wondering what a PARALLEL FLOW CONDENSER is, it's basically a newer and better design than the original tube and fin style condensers. A parallel flow type is reported to be about 30% more efficient.
You can buy one from Classic Auto Air or Coldhose or a variety of other places if you search: Universal AC Condenser. A universal condenser will be available in different sizes, but one in the approximate size of 16 x 24 inches like the above one will fit OK in any 240 (or see below for the larger 16 x 26 inch condenser I installed).
Later Factory 240 Condenser
If, by chance, you have a 1991-93 240, you should already have a superior parallel flow condenser, like this 1991-93 240 condenser shown above. This one above is unpainted, but typically the factory condensers were BLACK.
If you have the older tube and fin style (below), you can install a later one like this above with a bit of work or you can buy a universal type that may fit without a lot of work.
The design difference is pretty easy to see compared to this early style condenser above, which came out of a 1990 240.
I know you'll want to know this: A straight swap may not be always be possible. The locations or positions of factory AC hoses may not be quite the same between the two styles in a 240. The Volvo factory was not always consistent. Plus if you compare this condenser to the 1985 condenser further up above, you'll see the hose connections have changed over the years. So please understand you may need to change or create some hoses. If creating hoses is needed, you can read more about creating AC hoses further down or CLICK HERE.
As shown ABOVE, Aris mounted a low-profile 16 inch low-profile Spal PUSHER fan on the front of the universal condenser. Spal fans are an excellent choice. Very well made and very powerful. A pusher fan is recommended to get better air flow when you're stopped or at low speeds.
|Here's a photo below of my universal condenser in my 240. The size I chose was 16 x 26 inches, which I bought from Coldhose.
A single pusher fan would be fine, but in my horrible obsession for colder AC, I installed dual 11 inch pusher fans, which I mounted to my condenser.
If you're wondering why my horns are missing, I tossed them and mounted some more serious horns under the car.
I have a HORN PROJECT PAGE for that.
|Mounting the new AC Box in the DASH.
Custom Bracketry Fun.
The above photo is a view of the underside of the cowl (looking up) just below the center of the windshield. This is where the fresh air vent was located. I have closed it off and sealed it. Not because I hate fresh air. It's because the new AC box isn't designed to accommodate a fresh air vent and if I didn't seal it, I would have water coming in when it rained, which would be bad.
I began by cutting a rigid piece of plastic to the precise shape of the hole. It helped to make this piece out of cardboard first. Then after I had the cardboard size just right, I transfer the shape to the plastic (or you can use metal or whatever material you decide to use). Then I applied a generous bead of 3M black Super Weatherstrip Adhesive around the edge and installed it. Then I further sealed the opening with some Dynamat.
Those two brackets in this photo are the original sheet metal brackets that used to hold the top of the factory heater/AC box. As Michael did, I used those brackets as top mounts to help secure the new AC box.
240 HEATER HOSE ORIENTATIONAt the 240 firewall, the TOP hose always comes from the cylinder head. It feeds hot coolant to the heater core when heat is needed.
The BOTTOM hose is considered to be the return hose and returns coolant to the water pump metal pipe that begins behind the engine and goes to the back of the water pump.
2021 Update: Larger Ducts Added (click here)
<<< They sent 4 of these and they came in handy for my defrost vents. Strangely, these were NOT shown in their catalog. They are similar to PN 2-2028-4 in their catalog. The adapters I got were listed on my invoice as PN 0069-4. Cost was $12.50 each. SIZE: I measured them as 5 1/8 x 2 x 2 5/8 inches with an oval tube inlet made for 2 inch hose.
They sent 2 of these. These are defrost vents shown
in the catalog image as PN 2-1050. Cost was $17.50
6 3/4 x 4 inches. The top defrost outlet is about
5/8 inch wide.
I did not use these.
Michael Yount said he used some DIFFERENT defrost vents supplied by Classic Auto Air: Classic Auto Air PN 2-1053 and 2-1054. These are shown in the catalog pic above. He attached them under his dash using screws through the dash top.
I decided to go a different route using the original 240 defrost vents that you'll see below.
AC Refrigerant Hoses.
Traditional crimping and some alternatives.
Classic Auto Air has a selection of refrigerant hose parts, however their catalog did not have all the fittings I needed. I ordered the below hose parts from coldhose.com.
A parts inventory list with part numbers is listed below CLICK HERE.
C R I M P I N G C R I M P I N G C R I M P I N G
For hose fitting assembly, I already had a hydraulic AC fitting crimper that's used with traditional beadlock AC barrier hose. This is identical to the original hose used in the 240.
This tool was expensive. I bought it years ago when I first began doing my own AC work. It can cost $500.
If you decide to use a crimper, now there's a less expensive option for DIY AC mechanics. The Mastercool 71550 manual hose crimper. It can be mounted to a vise or to a bench. Best of all it's only around $150.
Or of course you can go to a hose shop and have your hoses custom made. You can expect to pay quite a bit for that service, so buying your own tools makes sense to me if you might be doing this more than once in a lifetime.
Hose Parts Inventory List
This list covers all AC hoses. All fittings are aluminum. Below items were ordered from coldhose.com.
This is behind my right side passenger kick panel.
My engine management system is here. In order to better organize the wiring you can see here I've added three more distribution blocks: Labeled 12 Volt Key 1; 12 Volt Key 2; and Ground.
12V Key 1 has power when the key is it the key first power "ON" position. 12V Key 2 has power in the key second (or "RUN") position.
There are no covers available for these distribution blocks. I made these cover custom because I wanted some protection for the hot leads.
I made the covers by forming some inexpensive 1/32 inch gray PVC plastic sheeting I got from McMaster Carr: https://www.mcmaster.com/#8748K21. I then painted them black and added labels. That PVC sheeting may be formed easily with some heat from a hair drier or heat gun and it's easily trimmed with scissors. If you try this, make a mock-up cover out of cardboard first so you have a good template.
I used Ester Oil for this system as recommended by Classic Auto Air. R12 systems typically always used Ester Oil. You may find information online suggesting the use of PAG oil with R134a. Either can be used. Both are synthetic lubricants. The difference is that PAG oil comes in more than one viscosity. Ester Oil comes in only one type.
Charging with Refrigerant
Classic Auto Air has some specific instructions for charging their AC systems.
Why do I need to VACUUM the system first?
Air conditioning systems don't like air. Air doesn't harm the system, but it's a lousy refrigerant, so you need to get it out of the system.
Air conditioning systems don't like moisture either. Moisture attacks metal parts and will eventually cause the compressor valves and rings to degrade or fail.
That's the main reason systems sometimes get vacuumed for hours. It's not the air so much as the water vapor that needs to be removed.
I tried to play by the rules.
I began by CHARGING WITH R134a FIRST.
<<< Can #2 took about 20 minutes.
Here are the final pressure readings after installing just under 24 ounces of R134a.
R134a Low: 27 PSI. High: 270 PSI.
CHECKING FOR LEAKSThis is something that will ALWAYS be on your mind when putting such a project together. My system developed a leak somewhere that allowed the refrigerant to leak down in 24 hours. That's a pretty fast leak. It makes you doubt the parts you spent a fortune on, your tools and your sanity.
<<< So I bought a can of R134a with UV dye and a UV flashlight on Amazon.
I started with 134a.
The air turbine in
this new AC unit is smaller than those in
original Volvo 240 air boxes. That
was easy to see since the new unit is more compact
than the Volvo box. So I expected the airflow on
HIGH setting would not be as powerful as the
original unit and I was right. I can't offer
a more precise quantification. If
this is a deal breaker for you, then you should
keep your original system.
Classic Auto Air specifies to use R134a in their systems.
I've never been much of a fan of R134a.
R134a is not as efficient as the old R12. But I did give it a good try in this conversion and tested it for a number of weeks.
If you're into this AC tech stuff and want to learn about SUPERHEAT and SUBCOOLING (and R134a comparison to Duracool), the below diagrams will help.
I've preferred using Duracool over R134a for a number of years. If you go to their site, you should READ THEIR FAQ SECTION to become more familiar.
Duracool is advertised to be 35% to 40% more efficient than R134a (it's more similar to the efficiency of R12).
It produces significantly lower head pressures than R134a.
Duracool says that the ideal low pressure readings with compressor running are recommended to be between 28 and 38 PSI (varying depending on the ambient temps).
They recommend that if the low pressure reading is too low, resulting in vent temps that are too cold, another ounce or two of Duracool can be added to bring those up.
Duracool recommends this can to be inverted during charging. This is because Duracool is a mix of more than one component and it will be more evenly distributed by inverting the can and allowing it to be charged as a liquid instead of as a gas.
In MY opinion, if you're going to use this entire 6 ounce can, then charging as a gas is just fine and it'll mix no problem after it's in your car. If you're charging using a large bulk bottle, then it will be more important to always charge inverted as a liquid to avoid depleting the bottle unevenly.
Single component refrigerants, like R12 or R134a (or Propane or Butane by itself), may and should be charged as a gas with the can upright.
I'm against recommending that anyone charge their AC system as a liquid like this, unless you're experienced enough to avoid damaging your compressor. If you are NOT experienced, I recommend doing more research or at least use lots of CAUTION. This is because if you don't use caution, you may inject an UN-compressible liquid into your running compressor, which has the potential to destroy it instantly. Feeding liquid refrigerant into a running system should, at the very least, be done very slowly.
If you have pulled a vacuum on your system because it was opened to the atmosphere for repair, Duracool recommends that a liquid charge to the suction (low) side of the compressor should occur initially with the compressor off. Then one should wait about 30 minutes for the liquid to boil off to a gaseous state and then move on to the next step of adding more with the compressor on. The use of an AC gauge manifold set helps greatly to regulate the whole process and permit the system to be charged in a more precise and controlled manner.
NOTE: LESS DURACOOL IS REQUIRED COMPARED TO R134a (or compared to R12a).
As mentioned, Classic Auto Air recommended 24 ounces of R134a for this conversion.
The Duracool equivalent is about 10 ounces.
Here's a table below showing precise conversions
(from the Duracool website FAQ section).
Here an information video from Duracool. (3:41 length)
MY ULTIMATE VENT TEMPERATURE PERFORMANCE WITH DURACOOL
Duracool is more efficient that R134a and in my system, it gets considerably colder.
This testing was done at idle and on the road.
INITIAL IDLE TESTING:
The first Duracool tests were done at end of summer 2017. With Duracool (while idling) I saw a low vent temperature of 27º Fahrenheit with an ambient temperature of 80º F. That ambient temp was not very high, but by this time cooler fall temperatures were coming. This vent temperature was recorded at idle in my garage with the fan on the lowest setting. As the AC continued to cycle on and off, the vent temperature ranged between 27º and 32 º F. Increasing the fan speed tends to bring the vent temperature up several degrees because more warm air is being pushed through the evaporator.
When summer 2018 came along, I did more testing with high ambient temperatures of more than 100º F. After initial start-up in my garage, vent temperature at idle was 46º F. Since 46º F felt pretty good with that kind of outside temperature, I was curious about my wife's new Subaru Forester. So I tested the Subaru AT IDLE with the same 100º F plus outside temperature. It recorded a vent temperature of 43º F. My 240 wasn't too far behind that.
2019 SUMMER ROAD TESTING:
While road testing at 55 mph with an ambient outside temp of over 100º F, I have recorded low vent temps of 25º F (PHOTO BELOW) however more common vent temps seemed to be around 31-32º F.
Yes, I will agree with you that allowing the temp to dip below freezing can introduce problems. See the below section on preventing FREEZE-UPS.
NET TEMPERATURE DROPS:
So it appears my potential vent temperature drop below ambient is around 53º-55º F at idle and around 68º-74º F degrees at 55 mph. This is awesome cooling compared to before!
Yes, this kind of performance makes me smile.
Any temps below freezing can have a potential negative affect. You should read the BELOW section on preventing freeze-ups.
There can be TWO different types of freeze-ups in an auto AC system.
FREEZE UP type 1.
This occurs when moisture in the air on the OUTSIDE of the evaporator turns to ice. This can happen when the outer surface of the evaporator drops below freezing and begins freezing the condensation moisture collecting on it. Small amounts of frost on your evaporator will not cause problems and when the frost or ice melts, it'll drain out to the bottom of the car. If the evaporator gets or stays cold enough for a long enough time, ice can continue forming much heavier. If enough ice forms over time, it can eventually block the flow of air going through the small evaporator coil spaces. This blockage will result in poor airflow through the vents and any air coming through may not be as cold as it should be.
Since you probably can't climb under your dash to look for ice on your evaporator, there are other ways to detect ice. A sign of ice forming can be found under your hood on your AC suction hose (low pressure hose). This image below isn't a Volvo, but it shows what you can find. This is frost accumulating on the pipe or hose coming from the firewall. This hose goes to the compressor or to the accumulator on a later 240. This is the return (suction) line for refrigerant returning from the evaporator to the compressor.
Ice forming on this line means things are usually too cold. Most often you won't see ice like this on a normal working AC system, but instead you'll see light frost or cold beads of water condensation.
Freeze up conditions are temporary and will not damage the system. It will, however, damage your sanity.
FREEZE UP type 2.
Another type of freeze-up can occur if there are traces of moisture INSIDE your system. If your evaporator dips below freezing (32º Fahrenheit) and if there are any traces of moisture in your refrigerant, that moisture can crystallize (FREEZE) as it enters the evaporator coil. If enough ice forms at the coil entrance, it can temporarily block the flow of refrigerant. If this occurs, then the first symptom will be the AC vents expelling ambient temperature air.
If you were to connect a pressure gauge manifold to your system when this is happening, you would see reduced pressure in your low pressure side (the line between the evaporator and compressor). This reduced pressure can even become a vacuum if the blockage in your evaporator is severe enough. If this occurs, there's not much you can do except turn it off and wait for it to thaw out, which can take hours. This INTERNAL freeze-up can be prevented or reduced by thoroughly vacuuming your system to remove air (and moisture) before charging it with refrigerant. Also replacing the receiver/drier canister will be a good idea if you suspect that an internal freeze-up has occurred, or if the drier canister hasn't been replaced in a long time (or ever), especially if the system has been opened or serviced and it wasn't replaced during that service. The drier canister contains a desiccant for moisture removal.
A new drier canister is not expensive and replacing it should be a matter of maintenance when the system is worked on.
Years ago when I was experimenting with PROPANE in my original Volvo AC system (CLICK HERE), I was able to get very, very cold AC at times, but I eventually gave up on propane because performance was too inconsistent. Considering that experience now, I think the problems I experienced might have been because of internal freeze-ups, since at one time I recall I getting under the dash with my laser temp reader and I measured the evaporator at 17º Fahrenheit.
Who knows? If I had found the below temperature controller back then (if it existed yet), my experiments with propane might have been a success.
RECEIVER/DRIER Canister: An old receiver/drier can become useless if the desiccant inside becomes saturated with moisture. This can easily happen if the system was ever left open or it the receiver/drier was sitting on a shelf for a long time and the seals weren't 100% air-tight. If you remove the sealing CAPS on a new receiver/drier and you don't hear the "PSSSSST" of rushing air, then it was not properly sealed.
So maybe you're thinking that YOUR AC system isn't getting anywhere near cold enough to freeze. This might be true, but keep in mind that vent temps can be higher than your evaporator exterior temps. So even if you might not be concerned about freeze-ups, there are ways to improve things. Keep in mind that my current Classic Auto Air system was designed to use R134a and I did use that at first, but after I got disappointing results, I switched to Duracool R12 replacement and that got the temperature down substantially.
|EVAPORATOR TEMPERATURE CONTROLLER
Injecting some higher tech into old school AC control.
Here's a new device I've been using for a while to control my evaporator temps from getting TOO COLD.
This is the BAYITE TCF-3A035 12V DC Digital Temperature Controller (in Fahrenheit) with internal 10A Relay and Sensor.
It can be found here: https://www.amazon.com/gp/product/B011VGAPOC/. Cost: $18.00.
There are nearly identical controllers out there from different sellers, but some versions use 110v AC, so avoid one of those if being used in a car. You can search "12 Volt DC Digital Temperature Controller" and you'll find them.
|Why would I need to better control my evaporator temperature?
I'm using this device to monitor the temperature of my evaporator outlet pipe and to allow me to see the evaporator temperature. Before using this I found that my evaporator was been getting considerably colder than 32º Fahrenheit at times.The main reason for this is because I'm using Duracool, which is considerably more efficient than R134a, which the Classic Air AC system was designed and calibrated for.
The programming functions for this unit allow me to program it to cut power to the AC compressor if my evaporator becomes too cold.
I have the sensor tip taped to the outside of my evaporator outlet pipe under my dash. I then insulated it with some foam tape.
The evaporator outlet pipe is the one that goes to the low pressure hose that returns refrigerant from the evaporator unit to the compressor.
This device is small, about 3 inches wide.
Programming it was not difficult once you read and re-read and then absorb what the instructions are telling you.
For this type of programming you would use COOLING MODE, which I have circled on the second image below of the CONTROLLER INSTRUCTIONS.
When I want maximum cold AC, which is usually what I use, I can set the programming to allow the AC compressor to run normally until the evaporator dips to 32º Fahrenheit. It then CUTS the compressor power and remains OFF until the temperature rises one degree to 34º.
This OFF-ON gap can be one degree like I set it for or any custom setting you like.
This device does an excellent job of regulating temps and I have not experienced a suspected freeze-up since I began using it.
Here's a video I made below showing how this controller regulates the AC temperature.
NOTE: That on/off switch on the right side is not part of the controller. I added that to switch off the controller power if needed. I thought that might come in handy, but so far I've never needed to switch it off.
WIRING DIAGRAM FOR MY INSTALLATION
Here's a simple wiring diagram I made for my use of this device. This controller simply INTERRUPTS or CONNECTS the ground circuit for the relay I'm using to turn on the AC compressor.
QUESTION: Can you use a device like this with any normal factory Volvo AC system?
Yes, OF COURSE.
If you somehow manage to get your normal AC to get super cold and you're concerned about it getting TOO COLD, this device would work just fine.
I know that some Volvo AC systems, such as the later ORIFICE TUBE systems, are capable of getting super cold, especially if you use a hydro-carbon refrigerant, such as Duracool.
QUESTION: Can I adjust the set temperature on this unit while driving without having to push a bunch of buttons to enter a programming mode?
YES you can.
Simply press the SET button. The set temperature will display. Then press the UP or DOWN button to change it. Then leave it and the unit will change back to default display in about 5 seconds. Your new SET TEMPERATURE has been changed.
NOTE: The RED LAMP next to "WORK" is letting you know the controller has switch ON your AC. When that lamp turns off, the controller has switched it off.
Here's a video I made below showing how the SET TEMPERATURE is quickly changed if needed while the AC is running.
If you have questions or decide to try one of these with your AC, let me know how it works for you. Send me an email. CONTACT
Here are images below of the instructions and programming guide. I circled the area in orange that I used for setting the cooling programming on mine.
CLICK IMAGE FOR LARGER PHOTO.
A downloadable or printable PDF of these instructions is here: https://www.davebarton.com/pdf/BayiteTCF3A035TempController.pdf
Update: May 2023
I've been using this system along with the above added TEMP CONTROLLER above for three years. This includes thousands of miles or driving with a number of trips across the entire country. So far it seems to work really well.
During road tests with outside temps of 100 degrees PLUS Fahrenheit, my AC vent temps have been consistently at mid to low 30s Fahrenheit at highway speeds.
Before, WITHOUT THIS TEMP CONTROLLER, my evaporator would definitely dip well below freezing (because that can happen with Duracool). So this device has been very successful at stabilizing temperatures to prevent freeze-ups.
If you've done an AC upgrade to your Volvo and you can share it or if you're thinking of doing something like this, please email me. I'd like to hear all about it.
Also, if you have any questions or suggestions to improve the information in this page, please let me know. Thanks, Dave
|Other Car Brand
||Center Cap Labels/Overlays
||240 Black Door Vinyl
||240 Power Mirrors - Switches
||240 Oil Cooler Page
||240 Fuse Panel Page
Racing 242 Turbo Page
||240 Hydraulic Clutch||Fuel Pump RELAY Page
||240 Headlight RELAY Page
|Used Parts & Extra Stuff for sale
||240 Ignition Page
||240 Headlight Page
|240 Gauge Electrical Diagrams||240 REAR END Page||Yoshifab Catch Can Install||240 MODS and FIXES Page|
||Gentex Mirror Upgrade||Yoshifab Drain Tube Install||Modified 240 Favorites|
|SoCal Salvage Yards||Unleaded Racing Fuel||B26FT Stroker||Dave's 245 Spec Page|
|240 SUSPENSION Page||240 Lowering Page
||240 Windshield Page
||240 WIPER Page|
||240 Dash Top Gauge Pod||Cadillac 4-Note Horn Install||240 DYNAMAT Installation|
|4 Speed Fan
||Electric Cooling Fan
||BRUSHLESS Cooling Fan Page
|240 AC Page||"KOMFORT BLINKER" Upgrade||T5 Trans Conversion Page|
|240 VIN Page||Stepper Idle Valve Page
|240 Exhaust Page||242 Power Vent Window Project||
EFI Volvo Pin Function Diagrams
||Volvo Meet Photo Albums||Texas Volvo Meets and Events|
|Ordering Instructions||Policies||PAYMENTS Page
||Mojave Road Trail Map Page
|Returns||Shipping||Shopping Cart Troubleshooting||Contact Us