Aftermarket || Flow Condensor 88' 740

Hey everyone,

I've searched and found that some prefer a parallel flow condenser when replacing the original meant for r12. But I have some concerns about the fittings and that if someone might be able to help out.

Car is a 1988 745 turbo with an r12 -> r134a conversion done sometime under a previous owner. Condenser in the car (currently blown due to corrosion) measures roughly 16"x24" and I'm looking at something like this

https://www.ebay.com/itm/A-C-Univer...=172034689468f74422cb69ac4cc3aa1f792aea64b090

Any help is appreciated. I'm also going with enviro safe refrigerant so hopefully this thread can just be about installing an aftermarket condenser. Thank you

If that envirosafe refrigerant is one of the newer more efficient ones. You won't have to do anything but get rid of the old stuff in there. Then make sure you are using a compatible oil as well as the better refrigerant and it should be ok.

Make sure the pusher fan is working. I would suggest adding a switch to it. Then it can run when the air is on instead of being a overheat fan.

If you still arent happy then I'd consider the parallel flow condenser. A 93-95 940 should have a parallel flow condenser stock. That may be one to adapt.

Thank you much dl242gt,

I'm in kind of a bind as I'm making a move 1000 miles away and the AC just sh*t the bed. I would be fine driving with no AC but don't want my dog to have to be hot.

I was also looking at stock condensers but no one seems to have any. I added a puller e-fan a while back as my pusher was frozen with rust.

the newer 940 condenser looks like it will physically fit but I'm not too sure on the making the connections work. Beyond getting all the lines off a newer 940 is there any way to make this work? Or to make the aftermarket condenser work?

Thank you

*Edit: after some more searching it seems to go to the r134a condenser in the newer 940s you need the lines as well*

Still would be great to know how to adapt one of the universal parallel flow condenser if someone has done this

If you are time conscious. I would go with the newer refrigerant. Its the easiest and least costly way to go. Fix any leaks and put in that envirosafe.

I have a 1990 740, with a new aftermarket compressor, converted to r134a (stock condenser). It blows under 40F vent temps in 100F ambient air temps. I’d just put a new stock condenser in there, properly convert to r134a (unless it is already), and vacuum/recharge. I have been totally satisfied with me, it blows as cold as 99% of r134a systems.

Oh and it’s still a stock clutch fan car with a normal functioning pusher that comes on with either a) ac pressure switch or b) overheat switch (which I’ve never even seen happen). It comes on all the time at idle with the ac on.

Hey, right on guys thank you much for the advice.

I was freaking out a bit when I posted. We are supposed to be on the road in less than a week.

Anyway, I've found a genuine unit and that will go in with new orings everywhere, ester oil, accumulator, orifice tube, vacuum, etc., and the enviro safe. I'm waiting on parts now and hope for a smooth install. When I bought the car we fixed the AC and it was great for years on r134a.

I'm still debating if I'm going with a variable or fixed orifice tube (I ordered both). Old one came out pretty clean but it seems using the variable could go either way in an old system.

Thanks again, I appreciate the help

moustacio said:

Hey, right on guys thank you much for the advice.

I was freaking out a bit when I posted. We are supposed to be on the road in less than a week.

Anyway, I've found a genuine unit and that will go in with new orings everywhere, ester oil, accumulator, orifice tube, vacuum, etc., and the enviro safe. I'm waiting on parts now and hope for a smooth install. When I bought the car we fixed the AC and it was great for years on r134a.

I'm still debating if I'm going with a variable or fixed orifice tube (I ordered both). Old one came out pretty clean but it seems using the variable could go either way in an old system.

Thanks again, I appreciate the help

Click to expand...

You should use the variable orifice tube and post your results I?d be curious to know. Could always swap it out for the fixed one after your road trip if it isn?t any good.

Fixed orifice valve is in, sorry. I don't think anyone will reclaim the enviro safe or I would have tried the variable one.

Quick question as I'm too tired and let's say medicated to have the brain working:
Should I use the r134a pressure switch that's on there now for the enviro safe, or do I need an r12 version?

Sorry for the question but I over tightened the pressure switch and split the threads to I need a new one anyway.

Thanks everyone, I'll let you all know how the alternative refrigerant works out

I've used a variable orifice valve for many years in my wagon. It is a good improvement in the really hot weather. in my experience it's worth the extra money. Maybe next time you have to service your system throw it in there.

Looking forward to hear how the enviro safe stuff works.

Hey, thank you dl242gt

I'm holding vacuum on the system overnight so there is still time to put in the VOV, I bought both when I ordered.

Also, it looks like I have an r12 pressure switch in there now. Apparently they are adjustable so I will read up on that. The enviro safe runs at different pressure than r134a so hopefully I will be able to get it right.

Thanks guys

I’ve never changed anything on my pressure switch. My system is r12 and has been filled with propane as well as r134a. It worked fine with both.

Hey thank you, one who hates Vulva people

Puts my struggling and simple mind to rest. I should have the switch in a few hours and charged soon thereafter. It looks easy enough to tinker with if I have any issues.

Thanks again fellas

Hey everyone,

Looking for some more advice on my AC system even though I used to be a HVAC guy for homes, buildings, etc. years ago. This may be long winded as I tend to be

Rundown of what I have done:
1)Got burned on my "genuine" condenser, so new aftermarket condenser in, new fixed orifice tube, new accumulator, all new o rings lubed with mineral oil except at compressor, new pressure switch, added 110ml/3.7oz ester oil (3 for drier, 0.7 for condenser)
2)vacuum down to max (~24inHG here at 6k feet) for a few hours and held for a day or so
3)charged less than 12 oz industrial enviro safe r134a replacement into system under full vacuum

Now with around 9 oz of the gas in the compressor is running and pressure was around 35psi on the low side with 95*F outside temp, maybe 10% humidity. Vents not blowing cold yet. I planned on weighing in the adjusted 14.55oz enviro safe (equivalent to 38.8 oz r134a) so I started to add more (maybe an ounce or two) and the compressor clutch starts to smoke and the low side pressure shoots up. Before killing the engine I notice the clutch spinning at maybe 1/8 speed.

Came back later and the pressure is normal and the clutch is operating normally. Haven't touched it since.

My head is fried with stress and all that with my move across the country so I'm not sure what to do. My car, 88' 740, has a muffleras Volvo calls it and I was able to blow some air through that line with everything apart. however it did seem a bit restricted, I chalked it up to oil in the line.

I don't know I may just take off the compressor belt and drive at night at this point. I have terrible night vision with photophobia. But any thoughts, ideas, etc is greatly appreciated for this burned out old goat.

Sounds like your compressor has issues if it was smoking. Don’t they say to charge that propane mixture NOT under vacuum?

And is 24” Hg the best you guys can get at 5k feet elevation? I’m much lower than that and always pull nearly 30”.

FWIW, r134 is so so cheap it’s worth giving it a shot. Can’t remember exactly how much I used in my 1990 but I wanna say I charged to roughly 80% and it took forever to get warm. So I added some more and now it’s almost immediately cold and blows a pretty reliable 40-44F, on 90+ days.

Hey there man thank you much for the continued help and thoughtful replies. Don't know how you were able to read through my novel there but I appreciate it.

Yeah, my compressor is likely done for. However, it hasn't given up yet. I'm still a hair undercharged but my vent temps have been around 50*F in 90* + weather. I pushed back my move so I'm trying to sneak up on a full charge. I wrote enviro safe and they confirmed that the industrial gas they sell, relabeled industrial es12, should be charged under max vacuum.

It would be nice to see what the high side is doing but when adding Es-12 with the compressor running the low side pressure starts to shoot really high. However, if I charge some gas, turn off AC and let things equalize for a while, the pressure stays rock solid and everything seems to work as it should. I'm not trying to kid myself that something isnt messed up but...

My brother suggested going back to r134a too but my conscious won't let me put anymore of that into the atmosphere. I know that I make negligible impact and I still drive around and all that.

Yeah the pressures here have always confused and given me anxiety before I realize we're at elevation.

Thanks again fellas and I'll let you know when my system fails on me and how the drive back to IL goes.

Thanks for keeping us updated on using the es12 stuff. Hope you get it sorted out and the move goes well.

moustacio said:

Hey there man thank you much for the continued help and thoughtful replies. Don't know how you were able to read through my novel there but I appreciate it.

Yeah, my compressor is likely done for. However, it hasn't given up yet. I'm still a hair undercharged but my vent temps have been around 50*F in 90* + weather. I pushed back my move so I'm trying to sneak up on a full charge. I wrote enviro safe and they confirmed that the industrial gas they sell, relabeled industrial es12, should be charged under max vacuum.

It would be nice to see what the high side is doing but when adding Es-12 with the compressor running the low side pressure starts to shoot really high. However, if I charge some gas, turn off AC and let things equalize for a while, the pressure stays rock solid and everything seems to work as it should. I'm not trying to kid myself that something isnt messed up but...

My brother suggested going back to r134a too but my conscious won't let me put anymore of that into the atmosphere. I know that I make negligible impact and I still drive around and all that.

Yeah the pressures here have always confused and given me anxiety before I realize we're at elevation.

Thanks again fellas and I'll let you know when my system fails on me and how the drive back to IL goes.

Click to expand...

That is odd, I can't find it on their website anymore but when I bought it, it said that it's supposed to be charged under partial or no vacuum. I wonder if they changed it.

Low (suction) side should go down when the compressor cycles on, not up.

Is r134a compatible with ester oil? I can't remember. I know that for r12 to r134a conversions, I've always just flushed everything and switched to pag46. Knock on wood, I still get 40F vent temps with an r12>r134a conversion car.

Hey guys,

** I'll put his up here so everyone doesn't have to read through my ramblings:

I put in another 0.4Oz of the es12 today and was getting vent temps from 36*F to 44*F just around town with the e-fan on low speed and blower motor at middle speed. No smoke or anything out of the ordinary so far. Before my condenser went I was getting low 40's at its best.

**

Hey thanks dl242gt, I'm hoping for the best and I'll let y'all know how the journey goes. I am planning on doing a few long rides here in CO first and will probably drive night and early morning for our move. I'll post back with how things are going, good or bad.

Yes I was concerned about the vacuum as well and I get the feeling that the company is intentially being vague on the website due to potential legal issue? I know they changed the labeling and that. That said, when I wrote them I asked if cooling performance would be affected by charging into a vacuum. They said that the industrial r134a replacement should be charged with the system under full vacuum.

I write with a lot of convolution but yeah the low side pressure drops as the compressor kicks on. My odd issue was/is that the pressure would go from say 30psi up to 50psi + while adding small amounts refrigerant. After waiting with everything off the system appears to be operating correctly with the pressure staying at the hypothetical 30psi. Also, I hope the ester is correct. looking back I should have flushed everything while waiting for parts and all that.

My brain is well fried by now but I'm thinking the compressor will go out.

Thanks again guys and sorry for my manic, long, rambling posts.

I think your compressor will be okay (well, aside from that weird smoking issue....) because people do those quick and dirty r134a 'conversions' all the time without changing oils and seem to never have issues.

Best of luck.

Finally put the car and AC to the test and made it out to Illinois. Beyond the evaporator freezing up where the weather had more humidity everything went great. Adjusting the pressure switch seems to have the AC working great but I'll let y'all know if anything changes. (I had to raise the pressure on the fly by turning the screw clockwise. Didn't have gauges but an 1/8th turn in my case let the compressor cycle on and off enough to work well)

It wasn't too hot on my trip but so far I'm happy with the EnviroSafe, the condenser, and the compressor seems to be fine as well. I'm guessing refrigerant hit the compressor as a liquid and that was the cause of it acting up. At most speeds the temperature of the vents and car is nice and frosty. At idle things warm up a bit but still cold and comfortable. The 740 has never had a better working AC since I have owned it over the last 10 or more years.

Thanks guys