'89 240 AC woes

[PromiseRing]

1989 245. Has an r134 low side fitting inline above the exhaust manifold. Not sure if that line is stock or not.

The 2 green compressor/drier wires were wrapped around the steering column and snapped. Need to check those for 12v. Anyway, charged the system to about 85psi (85F outside) and manually ran the compressor via 12v jumper at the battery. The condenser got pretty warm and the in-line filter (whatever black canister is in front of the condenser by the grill) was very hot; about 160F according to the IR thermometer. Nevertheless, vent temps were about ambient. Any idea why? Not sure why I get sucked into diagnosing everyone’s ac system but I am NOT ac proficient at all.

TL;DR ac no cold. Charged it; manually ran compressor and vent temps were still warm. Condenser and in line filter were both warm so the compressor is compressing at least a little bit.

I would assume that replacing the receiver drier is a minimum, as well as maybe the inline filter and orifice tube. Btw, the 740s vent temps are about 38-40F driving down the highway on a 100F day, so I’m doing something right.

[Cwazywazy]

High/low side pressures? You can get an AC manifold for like 30 bucks on ebay.

[90volvo]

Kinda unclear on your process. Is the 85psi the low pressure reading? If so you are way over or have air in the system or to much fridge. Your 245 does not have an orfice tube. It uses a expansion valve. If I was in your shoes, I would by a new dryer. Go rent a vacuum pump from autozone. intall the dryer then hook vacuum pump and run it for a few hours. Watch some youtube videos and learn how to use a gauge set and a vacuum pump. Charge you system up by weight is the best.

[PromiseRing]

Originally Posted by Cwazywazy

High/low side pressures? You can get an AC manifold for like 30 bucks on ebay.

I already have a manifold gauge set. No high side fitting on any of these volvos for whatever reason.

Originally Posted by 90volvo

Kinda unclear on your process. Is the 85psi the low pressure reading? If so you are way over or have air in the system or to much fridge. Your 245 does not have an orfice tube. It uses a expansion valve. If I was in your shoes, I would by a new dryer. Go rent a vacuum pump from autozone. intall the dryer then hook vacuum pump and run it for a few hours. Watch some youtube videos and learn how to use a gauge set and a vacuum pump. Charge you system up by weight is the best.

I thought it was about 1 psi per ambient temp with compressor off. Once i turn it on it drops to maybe 30psi or so. I guess having air in the system would cause it to not function properly but I was essentially just testing for slightly cooler air to check functionality of the compressor.

How often is it necessary to replace that black canister up front that appears to be an inline filter? We are getting a parts list together.

[Cwazywazy]

Originally Posted by PromiseRing

I already have a manifold gauge set. No high side fitting on any of these volvos for whatever reason.

I thought it was about 1 psi per ambient temp with compressor off. Once i turn it on it drops to maybe 30psi or so. I guess having air in the system would cause it to not function properly but I was essentially just testing for slightly cooler air to check functionality of the compressor.

How often is it necessary to replace that black canister up front that appears to be an inline filter? We are getting a parts list together.

Pretty sure all 240s have high/low fittings on the back of the compressor. Or at least all mine do.

[ZVOLV]

My r12 1990 240 has two fittings on the back of the compressor, but only one of the r134 fitting adapters threaded on there.. I just recovered and recharged thru the low side with the machine and months later I'm still blowing cold on r134.

1992 240 I saw in JY was 134 and has a high and a low. Low on the drier. High on the line by the drier.

Saying you charged it to 85 psi means you dont know what you are doing. You go by weight, not pressure.

When I get a car for an AC complaint, like I have now, the first thing I do is recover the system and weigh what comes out of it. If its low-look for leaks. If its not, I start to suspect the co pressor.

I doubt you are recovering the refrigerant from these AC jobs you are doing. I don't agree with polluting just because you want to save money and don't have access to the proper equipment.

[PromiseRing]

Originally Posted by ZVOLV

My r12 1990 240 has two fittings on the back of the compressor, but only one of the r134 fitting adapters threaded on there.. I just recovered and recharged thru the low side with the machine and months later I'm still blowing cold on r134.

1992 240 I saw in JY was 134 and has a high and a low. Low on the drier. High on the line by the drier.

Same with me regarding using the low side only. Have yet to see a high side fitting on any of the volvos. There might be one on the back of the compressor but it's still the r12 fitting on the pre 93 cars. I've read many ifferent posts stating there's no high side fitting, regardless of what's on the back of the compressor.

Anyway, there are 2 green wires coming from the firewall for the AC. Does one go to the compressor and one go to the drier, and if so does polarity matter?

Here's the wiring diagram which again I am not good with.


Seems that there are multiple switches in the diagram. Is the one labeled "pres sens" going to be the low pressure switch located on the receiver drier?

I think that would leave "thermostat sw" to be the rheostat that you turn to turn the ac on (in dash). I have never owned an older 240 with functional ac so I'm not sure how this works.

[Cwazywazy]

I just use an R12 AC manifold. I think knowing the high side pressure would be useful here.

[PromiseRing]

So looking at this diagram I have some questions. There are 2 green wires in the same sheathing coming from the firewall area. Is one of them supposed to go to the compressor power wire, and one of them is supposed to go directly to the pressure switch on the receiver drier? According to the diagram only 1 green wire comes from the ac relay and goes straight to the thermostat switch. Not sure why I'm seeing 2 green wires at the firewall. Is the 'thermostat switch' the rheostat that is for the ac control? (dial on the dash). Plz help before I catch us on fire.

[PromiseRing]

Alright so I rewired the system and got the compressor to kick on by itself. After that I replaced the receiver drier, vacuumed the system, and recharged with 36oz of r134. I charged the system under vacuum.

Air vent temps are ambient or a hair below ambient, at least when revving. Compressor is on, condenser is hot, in-line filter is hot, what should I look for next?

I do not have a high side reading.

[DET17]

The 89 2 series has an R12 TXV (thermostatic expansion valve)...... you should convert yours to the upgrade R134a, which my son tells me is still available.

When you vacuumed down the system, did you close the vacuum pump valve and watch the vacuum levels? It should have been rock steady for ~30 minutes or else you have leaks.

Find your original charge weight in grams for the R12 system, then you charge with ~ 85% of that in R134A.

You really don't have any need for the high side connection to charge. Get a weigh scale and charge EXACTLY by net weight of R134a.

Your low side reading will depend upon ambient temp & RH, at the time you are charging the system. A reading in the low 40s is much closer to ideal. If you didn't get the air out, your low pressure will be as high as you are quoting and it won't cool for squat !

[jjona5]

I just threw away an adapter that was on the output of my old drier that put a high side tap there. That said, my car had a plugged up high pressure line after the dryer gave up. My car was a 90 and the dryer was the factory volvo one. Might want to loosen the small line going to the expansion valve and see if there is desiccant in there.

[JohnLane]

OP are you certain that warm water is not finding it's way through the heater core? Evaporator is in front of heater core + it takes very little coolant flow to warm up that air.

Hose pinch pliers on a heater hose is effective.

[PromiseRing]

Originally Posted by DET17

The 89 2 series has an R12 TXV (thermostatic expansion valve)...... you should convert yours to the upgrade R134a, which my son tells me is still available.

When you vacuumed down the system, did you close the vacuum pump valve and watch the vacuum levels? It should have been rock steady for ~30 minutes or else you have leaks.

Find your original charge weight in grams for the R12 system, then you charge with ~ 85% of that in R134A.

You really don't have any need for the high side connection to charge. Get a weigh scale and charge EXACTLY by net weight of R134a.

Your low side reading will depend upon ambient temp & RH, at the time you are charging the system. A reading in the low 40s is much closer to ideal. If you didn't get the air out, your low pressure will be as high as you are quoting and it won't cool for squat !

Yup I vacuumed the system then closed valves and left the gauges on there, it held vacuum fine. This car actually had pressure in it for a long time so I doubt there was a leak. I charged it with about 32-34oz of r134. This is close to 85% of the original r12 charge. I know this isn’t exact but it doesn’t exactly need to be perfect to get better than ambient temps. I just fixed the 93 940 in the same manner and it’s ice cold.

Anyway, upgrading the TXV to the r134 is something we can do, unless it’s very difficult to get to. Where is it? Thought it was in front of the evaporator near the heater core. I’m not going to rip out the whole dash until we need to.

Originally Posted by jjona5

I just threw away an adapter that was on the output of my old drier that put a high side tap there. That said, my car had a plugged up high pressure line after the dryer gave up. My car was a 90 and the dryer was the factory volvo one. Might want to loosen the small line going to the expansion valve and see if there is desiccant in there.

We also just replaced the receiver drier and new seals. I’ll need to locate the expansion valve.

[JohnLane]

OP it is helpful to know high and low side pressures.

You make a lot of work for yourself firing the parts cannon at it.

Also.... Do you hear the fan roar at idle with A/C on? The rad fan needs to get the heat out. Tropical fan clutch does well for this.

[PromiseRing]

Originally Posted by JohnLane

OP it is helpful to know high and low side pressures.

You make a lot of work for yourself firing the parts cannon at it.

Also.... Do you hear the fan roar at idle with A/C on? The rad fan needs to get the heat out. Tropical fan clutch does well for this.

??? I have not fired any parts cannon here at all. All i did was replace the receiver drier which is what you’re supposed to do on a car that has not had functional ac in a long time. There is no pusher fan or mechanical puller fan on this car, it’s an 89 and has been converted to a turbo car using an electric fan due to space limitations. I even misted the condenser with my pressure washer and left the efan on the whole time, still not much of a changed

The ac isn’t *terrible* while cruising but it is far from ideal. As others have said I may need to adjust or swap to a newer TXV. We may get the r134 out of there and use ES12A like in the 740 (works very very well).

[DET17]

Sounds like your charge is near appropriate. As the 89 doesn't have a pusher fan.... and I'll presume you have not E-fan converted, you need to take your delta T readings driving at say 55mph. If your low side pressure matches the tables (have you found them?) then the AC cycle is functional. It sure sounds like your heater core is flowing engine HOT coolant and killing your AC delta. Quick test: disconnect the coolant lines and join them with a copper 90* fitting.... an old SAAB trick as their heater valves fail near continuously. Don't use a plastic 90*, only copper for testing (I had a SAAB 900 running several years this way each summer).

Your condenser must "give up" the heat you extract.... it must have flow across it to do so. Have you cleaned the coils, or is it splattered solid with dead bugs & road grime?

[PromiseRing]

Originally Posted by DET17

Sounds like your charge is near appropriate. As the 89 doesn't have a pusher fan.... and I'll presume you have not E-fan converted, you need to take your delta T readings driving at say 55mph. If your low side pressure matches the tables (have you found them?) then the AC cycle is functional. It sure sounds like your heater core is flowing engine HOT coolant and killing your AC delta. Quick test: disconnect the coolant lines and join them with a copper 90* fitting.... an old SAAB trick as their heater valves fail near continuously. Don't use a plastic 90*, only copper for testing (I had a SAAB 900 running several years this way each summer).

Your condenser must "give up" the heat you extract.... it must have flow across it to do so. Have you cleaned the coils, or is it splattered solid with dead bugs & road grime?

Car has an efan and temps were a bit better while driving as expected but still sub par. Condenser is clean and I even sprayed water on it at idle to dissipate heat better. Made about a 5F difference. We can try to bypass the heater core although I do not think that is the problem, but we will find out.

As mentioned before putting r134 in a stock r12 Volvo system generally does not yield great results. The TXV needs to be upgraded as does the condenser and maybe even compressor. That is more work than my friend is wanting to do so he will likely end up giving some ES12A a shot. The r134 works pretty well in a 93 940 though.

[DET17]

A proper functioning system will give a 20*F delta across the evaporator. Forget outside temps for any reference other than charge high/low pressures.

How is the Efan being controlled?

My money remains on a Hot heater core......

[PromiseRing]

Originally Posted by DET17

A proper functioning system will give a 20*F delta across the evaporator. Forget outside temps for any reference other than charge high/low pressures.

How is the Efan being controlled?

My money remains on a Hot heater core......

Yeah he is leaving me with the keys so later this week I will temporarily bypass the heater core. The e-fan was being controlled by a temperature probe in the radiator and had no problems keeping the car at normal temps around town. On the highway it wanted to creep up especially after a nice long pull in boost. Now we have the fan hardwired to come on with key position 2.

I know this is not ideal but at lower speeds it is not a problem at all. So the fan was constantly on while we were idling with the AC on. We need to bypass the temperature compensation board to get a better idea of what temps are doing. Either way spraying the AC condenser is more than efficient enough to dissipate way more heat than it would on the highway so I highly doubt heat dissipation is the issue here.

[DET17]

The radiator is marginal if it is creeping after a boost pull. A good radiator will drop 10*C, 20*F across the tubes. His setup is generating more thermal load than that radiator can expel. Running an E-fan constantly is wasteful and will wear out that 12V motor sooner than later. He needs to have an 82*C switch in that radiator exit side tank... with a 92*C T-stat that should work well and the E-fan won't run when cruising the highway.

[PromiseRing]

Originally Posted by DET17

The radiator is marginal if it is creeping after a boost pull. A good radiator will drop 10*C, 20*F across the tubes. His setup is generating more thermal load than that radiator can expel. Running an E-fan constantly is wasteful and will wear out that 12V motor sooner than later. He needs to have an 82*C switch in that radiator exit side tank... with a 92*C T-stat that should work well and the E-fan won't run when cruising the highway.

Radiator is new. It’s just the compensator board I’m sure. It read ‘overheating’ at like 195-200F. Obviously it is at fault.