The great 240 AC system information dump + How to improve AC performance

[leecatd8209]

Random question:

Is the parts store dupont R134a at $15-20/can superior to the Walmart variety that's $4.88/can?

[TestPoint]

No.

Both the parts store and Walmart have added valves, hoses and meters to make it easy for amateurs' to test and add r134 and the prices for all above just a can of gas makes it a little hard to compare.

Just gas with oil is OK, gas with oil and dye is OK. Gas with a leak-stop is NOT OK.

[hillofbeans]

Originally Posted by volvohyes

Interesting. I looked at the switch on my 92 and I see no such adjustment screw. It has Volvo part #3537866

I got so much from this thread! I wanted to contribute a little by answering the question above. This is a question I had as well. There is no adjusting screw on the stock pressure switch (at least on my 1992 240). I came across the answer when I got a replacement for my stock pressure switch from the local AutoZone. The switch looks different and requires a new harness connector. But the adjusting screw is there and the part worked just fine for me. I think it is Santech A/C Switch part MT0207. Do not get the Santech switch for the 1993 for your conversion. It is a slightly different port size and won't fit on the 1992 and earlier R12 system dyer/accumulator port. Working pressure for this Santech part MT0207 is noted on the switch. I think it kicks on at about 25psi. I ended up not adjusting it because the AC seems to work just fine as is. My own R12 to R134 project is detailed with lots of photos at https://volvoforums.com/forum/volvo-...nstall-107142/

[VolvoLatAm]

Do the expansion valves come pre-turned? Which way do you use the allen wrench to open them the proper amount, right or left?

[dbarton]

Originally Posted by VolvoLatAm

Do the expansion valves come pre-turned? Which way do you use the allen wrench to open them the proper amount, right or left?

Yes they do, but everyone has different opinions/conclusions on what those settings should be if you think about changing it. You'll probably only find 134a versions now anyway.
Dave B

[VolvoLatAm]

Originally Posted by dbarton

Yes they do, but everyone has different opinions/conclusions on what those settings should be if you think about changing it. You'll probably only find 134a versions now anyway.
Dave B

I have an r134a expansion valve type. How did you figure whether to open or close the valve more? Could this cause too high of pressure in the system if done incorrectly?

[dbarton]

Originally Posted by VolvoLatAm

I have an r134a expansion valve type. How did you figure whether to open or close the valve more? Could this cause too high of pressure in the system if done incorrectly?

No. What it could do it create an incorrect expansion of refrigerant gas into the evaporator, which is what causes it to get cold. It needs to be just right to be efficient and the setting is different for R12 or an R12 replacement. No one on TB has ever expressed a clue how that setting should be adjusted if you need to change it for something other than R134a.

[Cwazywazy]

I need to adjust mine. I put it at 5.5 turns and I only get about 60 out the vent, whether its 70 or 90 degrees out. Something about superheat, stuff I don't understand, etc. I'll probably just set it to 10 or 12 turns next year, or whenever I feel like it. I have a few cans of es12a left so if I don't get adequate cooling after that I'll go r134.

[dbarton]

Originally Posted by Cwazywazy

I need to adjust mine. I put it at 5.5 turns and I only get about 60 out the vent, whether its 70 or 90 degrees out. Something about superheat, stuff I don't understand, etc. I'll probably just set it to 10 or 12 turns next year, or whenever I feel like it. I have a few cans of es12a left so if I don't get adequate cooling after that I'll go r134.

And so the cycle of trial and error begins. I have a feeling that using a "turns in" or "turns out" method of measurement will ultimately be meaningless. There are a number of manufacturers of TXVs and they probably set them at the factory based on flow or output pressure. One manufacturer's TXV at 5 turns may be very different than another's.
Dave

[Cwazywazy]

Originally Posted by dbarton

And so the cycle of trial and error begins. I have a feeling that using a "turns in" or "turns out" method of measurement will ultimately be meaningless. There are a number of manufacturers of TXVs and they probably set them at the factory based on flow or output pressure. One manufacturer's TXV at 5 turns may be very different than another's.
Dave

I think the correct way to do it is with low/high pressure readings and evap temp, then some wizard stuff to figure out exactly where it needs to be. And yeah, my cheap reproduction txv probably doesn't behave exactly the same as a 40 year old oem one.

I can't even read my high side anymore, so I'm just gonna guess. In the last page I mentioned that I found what certainly appeared to be a factory undisturbed txv set to 13 turns out. ¯\_(ツ)_/¯

[dbarton]

Originally Posted by Cwazywazy

I can't even read my high side anymore, so I'm just gonna guess. In the last page I mentioned that I found what certainly appeared to be a factory undisturbed txv set to 13 turns out. ¯\_(ツ)_/¯

And that was an R12 or 134a TXV?

[Cwazywazy]

Originally Posted by dbarton

And that was an R12 or 134a TXV?

I don't know what year, but it was an older unit so r12. (I wanted a thermostat and he gave me the entire hvac box with the thermostat hanging off)

[JCGMS]

Originally Posted by QisofrKuin

This thread could not have come at a better time.
I recently bought an '81 244 DL, and I was told that the ac system had been converted to R134a at some point, and it looks to my untrained eye that they replaced the drier and the compressor, though admittedly I'm not certain. However, the line that leads from the drier through the firewall to the evaporator is damaged, so all the refrigerant is long gone and I can't test anything yet. Perhaps some of you who have updated your systems and had to redo the tubing can tell me, did you have to take apart the dash to replace the drier-->evaporator tube? Or can that be replaced without such drastic action?

Did you figure this out? On my 87 I can see the side of the evaporator where the hoses connect pretty easily by removing the glovebox. I didn't take a photo but it takes < 5 minutes to get it off.

[ams]

To pull an old thread up,
We made a trip down to Ft Bragg for some training and it is HOT here. And the AC isn't what it used to be. Although, the last time we re-charged it we were in the back of an oreileys in AZ after racing a jeep to get to the next camp site on the north rim of the grand canyon... (we won; except we rattled the AC fittings loose...)

That said, we now have a little one and it would be nice not to cook all of us on the 89 245.

Before this thread I was happy to just keep plugging the old style along and be content with having mediocre cooling. Now I am motivated to see about making the AC amazing.

Parts I am seeing that I need:
Compressor

Evaporator


New Style barrier hoses

The tool to crimp the hoses.

Still need a condenser, expansion valve, pusher fan and ideally the '93 firewall.
If I were to order from Coldhose.com do we know the size condenser?
On the expansion valve, just get stock from FCP?
I have a genuine fan but in a couple threads the word is that modern china junk pushes more air than the Volvo fan, correct?
Despite having a sticky parts thread, most of the websites are down or changed to something else. Does anyone have a source for the firewall parts to make the '93 evap fit?

Anything else I am forgetting?

Hope you all have an amazing Wednesday!

Andrew

[dl242gt]

What refrigerant are you planning to use?

You'll want the parallel flow condenser and a pusher fan. Spal fans are a good product. I tie the fan into the compressor cycle so when the compressor runs the fan runs. It also has an override switch to run the fan all the time.

[dbarton]

Originally Posted by ams

If I were to order from Coldhose.com do we know the size condenser?

The original condenser is 15.5 x 26 inches. So you could fit a 16 x 26 or smaller. Coldhose offers a 16 x 26 (that's what I use).
Dave B.

[bkaushansky]

Same boat as ams…

‘88 245. Looking to replace all engine bay parts with r134a compatible ( hoses, dryer, compressor, condenser, new TXV). I want to leave the evaporator in place and just flush it correctly.

Can someone confirm I’ve got this right, that the original evaporator can be used but performance will suffer. I’m in northeast and don’t need the same level of service as my southern brethren.

Thx.
B.

[OldCarNewTricks]

Does any manufacturer still make the 91 up condensers? I can't find any.

[dbarton]

Originally Posted by OldCarNewTricks

Does any manufacturer still make the 91 up condensers? I can't find any.

It appears the aftermarket does. These are a bit expensive, but maybe they fit without needing new hoses?
Says for 91-93.
https://www.ebay.com/itm/25463268014...EAAOSwMVZe8VSM

Says for 90 and older, but it's a parallel flow type.
https://www.ebay.com/itm/36302875883...wAAOSwqpJe8VD7

Dave B

[white855T]

91 and up. https://www.ebay.com/itm/40155638548...mis&media=COPY

Same condenser, less money.

[OldCarNewTricks]

It appears that ad for the Nissens one is out of stock. There are a couple sellers across the ocean that are ~$260. I wonder if the ones Dave posted are Nissens brand, as well.

Pretty spendy, but what isn't nowadays. Thanks for helping me track down the part number, guys!

[white855T]

Originally Posted by OldCarNewTricks

It appears that ad for the Nissens one is out of stock. There are a couple sellers across the ocean that are ~$260. I wonder if the ones Dave posted are Nissens brand, as well.

Pretty spendy, but what isn't nowadays. Thanks for helping me track down the part number, guys!

Use the nissens part number to search on Ebay. There are a number of sellers.

[90volvo]

heres a crimper that Ive been using. Ive done probably 100 crimps counting battery cables and still works fine.
https://www.ebay.com/itm/11530767912...3ABFBMqIfkurBg

[Kjets On a Plane]

Originally Posted by dbarton

And so the cycle of trial and error begins. I have a feeling that using a "turns in" or "turns out" method of measurement will ultimately be meaningless. There are a number of manufacturers of TXVs and they probably set them at the factory based on flow or output pressure. One manufacturer's TXV at 5 turns may be very different than another's.
Dave

Years ago, when Volvo offered the 'R134A conversion kit' if you did it right in the 240 it came with what looked like the later type EVAP with a TXV of some sort & a new 220CC R134A appropriate displacement compressor instead of the 160cc or smaller displacement compressors on the 4-banger 85-92 R12 240s & some ester oil that was compatible with whatever residual R12 mineral oil was on the hoses even after a good flushing...

The duracool needs the orifice size, compressor displacement & expansion space similar to R134A, but the high side pressures & high side fan switching even lower than freon R12 that its about as efficient as to work optimally.
I'd use the R12 1992 primary fan brown switch off the 1992 7/9 e-fan cars in 91-93 240s high-side switch location to switch the pusher fan on at a lower pressure.
A variable orifice valve for R134A (if the system is known totally clean, otherwise just fixed orifice tube/less to go wrong).
And an adjustable (off pre 1991 7/9s or 1991 240s) low pressure clutch cycle switch when using duracool to get the most out of it on a 1993 system swapped 240 since it runs low side pressures pretty crazy low to get the phase change/charge weight right with the water-free propane/isobutane that that stuff is.
Tropical fan clutch, 3-row radiator, Bosch 100A E-fan 940T 100A alt (or denso if that's what fits and it doesn't get too hot where you live over the black top) & some air guides all in place to shove the air thru the sammich help as does a healthy pusher fan recombining the junkpile.

Tough break as you say. That later R134A sized evap is LONG since NLA for the TXV 240 R134A dealer retrofit kit.
&, I'd rather have TXV & the dial/t-static switch to turn it down/run it less/save energy if I don't need as much BTU exchange, as it's more efficient, and, on a turbo model (or larger engine swapped/more crowded engine bay 240), I wouldn't want the CCOT GM/Harrison 1991-1993 system accumulator in the engine bay if I could help it.

Some enterprising individual needs to figure out how to recombine the junkpile to use the 93-95 220CC R134A compressor, route the lines not thru the front sheetmetal more like the 1991-1993 models with better hoses less prone to chafing or leaks & nice form-fitting hard lines/easy to remove compressor & use the later style EVAP as Volvo more or less supplied (I wonder what GM car that comes in with fittings that Volvo found a TXV for in the dealer R134A retrofit kit??).

Make the engine bay less busy, compressor/hooptie accessory bushings less fussy & give more engine bay space than just swapping a complete 1993 system in (BTDT a bunch of times), especially if you don't want the accumulator in the engine bay and want variable T-static control which did work well when it worked/didn't leak with the R12 installed, but obviously that stuff is $$$ & not really legal/ethical to use, sooo

If someone else has to service it, totally understandable to set it up with all R134A stuff, but for shade tree hack owner-operator shens, not worried about ~6.0oz of 'dry' no water content propane/isobutane ZOMG burning me to death and don't want to pay dupont their blood money for their poisonous inefficient R134A they hold the patent on...

Originally Posted by Harlard

Might be only me, but my ‘93 AC setup does not have a high side port.

Remove the pusher fan switch to tap into the high side for a gauge reading after vacuuming & charging by exact weight with synthetic oil + quality gas on the 1991-1993 system...n00b...

Jump the push fan to just run while charging to make the refrigerant contract/get it ingested easier with the fan on low & engine fast idling at 1500rpm or so with the tropical fan clutch roaring away with healthy belts & low switch jumped, but don't let the evap ice or compressor get slugged...(there's usually enough safety factor that the refrigerant should boil in the accumulator, but the evap might turn to a block of ice pretty fast with the fan speed only on 1 depending on outside ambient temp/humidity). In AZ humidity isn't always an issue...

[Harlard]

Originally Posted by Kjets On a Plane

Remove the pusher fan switch to tap into the high side for a gauge reading after vacuuming & charging by exact weight with synthetic oil + quality gas on the 1991-1993 system...n00b...

Jump the push fan to just run while charging to make the refrigerant contract/get it ingested easier with the fan on low & engine fast idling at 1500rpm or so with the tropical fan clutch roaring away with healthy belts & low switch jumped, but don't let the evap ice or compressor get slugged...(there's usually enough safety factor that the refrigerant should boil in the accumulator, but the evap might turn to a block of ice pretty fast with the fan speed only on 1 depending on outside ambient temp/humidity). In AZ humidity isn't always an issue...

I had a chance to use a 93 940 compressor and didn't take it. Maybe I'll swap one over if/when it's apart again.

Currently using the ECU to trigger a fairly well-sealed 940 fan at low speed whenever AC is requested. High speed mode is triggered by the pusher fan switch. No mech fan nonsense for me, at least for now.