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240 Are the 91-92 heater/AC units superior to previous?

D

DET17

Reformed SAABaholic
Joined
Nov 1, 2009
Location
NW Georgia
for reasons other than age?

Planning my 242 restification.... and I had check marked getting one of these last versions of the HVAC units underdash. Might have been a Wagonmeister thread I saw that suggested the latest were the bestest. I know it's a real good time to pull one of these babies, and I've already got replacement blower motor, resistor and fan blades inhand.

If you've got the facts, please share. Fighting one of these out of a pullapart wreck not my idea of a fun Sunday, but I'd do it if the gains are worthwhile.

NOTE - Car "might" get AC, might not ;-), so evaporator differences perhaps moot.
 
All the '91+ systems had a different HVAC box with larger evaporator, an auxiliary pusher fan in front of the condenser, and an orifice tube setup (versus the older style expansion valve). The 1993 cars got R134a from the factory, and while that setup was similar in design to 1991-1992, most of the under hood parts were unique to that year only.

The later style is definitely superior in performance and reliability but not necessarily required for decent cooling. If you are going to stick with R12 or maybe an R12 replacement (I have no personal experience with these) and have a properly working original system, performance should be adequate. If you convert the old system to R134, cooling will likely suffer unless you upgrade the condenser and/or compressor.

Are you planning an engine swap in the 242? Keep in mind the later style accumulator and hard lines are more intrusive in the engine bay at the firewall.
 
Upgrading for the later version is better imo. Requires some time but not difficult. The entire dash including the old heater/act box.. Plus the right hand firewall pannel.if your 242 is pre 1981 the dash will also need to be upgraded. Also you need all the newer wiring. Next the condenser and all the plumbing. Yes it takes some effort.
 
While I do agree the later system is better because of the larger evaporator and getting the pusher fan for the condenser. I have an 82 242 turbo and the older system with R12 was always adequate for the summer weather. If you are already ripping the dash out and putting in a new dash I can see it being something to do in that case. But I wouldn't do it just to do it. You can upgrade the condenser and add a pusher fan easily to improve the old system. All I did on my turbo was add the pusher fan. If you can stick with the R12 your older system will work fine.
 
Yes, an engine transplant/upgrade is planned. Original 84 condenser will be gone.

I had heard that 91-> 93 were the years to get.... to source the under dash elements.

Is the only part of the evaporator/heater core system which is improved is the size of the evaporator? I know expansion valves are close to the evaporator.... but the orifice tube in my daughters old 91 240 was inline along the pass. side hardline near the alternator. My Dad and I had fun finding that orifice tube!

Thanks guys.... I'll keep an eye out for a 91-93 donor.
 
If your car is a coupe/sedan, you could probably sneak by with an upgrade to the condenser. While it's true that the evaporator is larger in the later cars, we've converted several early ones to a parallel-flow condenser and r-134a and had good results. It really depends on how much work you're willing to put in it. With the early cars, most of the work is getting a condenser to fit well while with the later ones, it's all dash/evap work. The '86-'90 cars can be fitted with a '93 condenser, but it's a lot of work mating that to the expansion valve system those cars used. Not impossible, but it does take quite a lot of fitting.

My '93 wagon blows very cold air and I'm really satisfied with the level of a/c, but my '83 with upgraded condenser does as well.

How much a/c work have you done?
 
Wren said:
How much a/c work have you done?
Click to expand...

My Dad did commercial AC for around 25 years.... I have his tools now and have converted / repaired several vehicles.

Good suggestions Wren, thanks man! After I get all the performance parts fitted, we'll see if there is room left for a condenser. :-P
 
I think I've accumulated all the parts needed to convert my '85 to a '93 r134 setup, but haven't done the conversion yet. Here's a link to one conversion discussion:
http://forums.turbobricks.com/showthread.php?t=322912

If you haven't seen them yet, cleanflametrap has a great set of tutorials on pulling the dash and replacing the blower motor. If you're pulling the entire heater box, the only extra that I'd add is to bring some long (18"+) 1/4" extensions so that you can unbolt the top heater box brackets more easily.
 
DET17 said:
My Dad did commercial AC for around 25 years.... I have his tools now and have converted / repaired several vehicles.

Good suggestions Wren, thanks man! After I get all the performance parts fitted, we'll see if there is room left for a condenser. :-P
Click to expand...

The last one we did was in an '83 Turbo. I can find out which parallel-flow condenser we used if you would like. It too quite a lot of fitting to go together.
 
Well a 93 240 just hit the radar screen..... looks like I'll be loading up the tools next weekend.

So Mr. Flametrap has tutorials on the dash removal? I've read the fastest way to the HVAC CPU is from the top (sans dash cover). I'll try and harvest all the hard lines out to the filter/dryer. My future compressor is from a 93 960, so I expect I'll need those lines later, perhaps with some adjustments to clear the powerplant. Conner, you said the condensor is a 1 year only in 93? Can't believe it will have survived all these years, but I'll give it a look.
 
The condenser in a 93 is a one year only design. Parallel flow vs sequential. That is what makes it cool better. Just get the compressor with it. If the 93 960 compressor is the same used from 95 on, it isn't going to work for you. Everything about it is different, line connections, pulley, mounting features etc.
 
2manyturbos said:
Just get the compressor with it. If the 93 960 compressor is the same used from 95 on, it isn't going to work for you. Everything about it is different, line connections, pulley, mounting features etc.
Click to expand...

The 93 960 compressor should work fine with my B5244T5. I'll just need hose connections.... the 93 still has individual lines/hex nuts for the line connections. I will have to study the early 960 a little closer next time I'm in the yards.... I know that late 960/S90 has a combined PLATE bolt on connection at the compressor that won't work.

Thanks for the tip on the 93 condenser ;-)
 
Good thing I found this thread. I just overpaid for a wrecked 93 245 to use as a parts car, I plan on retrofitting the complete HVAC system in to my 89 245 with a shot AC system. The donor car took a hit to the front end, but I believe that the condenser and fan are OK. The technical part will be wiring it all up.
 
Well I hit paydirt yesterday at the ATL PnP South (and met a fellow TBer Matt86 as we were cannibalizing the same 93).

Extracted the ENTIRE HVAC system from the 100k mile 93 240 (R134a stickers factory).... except the compressor which Matt needed. 1year only condenser & fan, complete line set & dryer/filter, and the legendary 91-93 HV blower with evaporator. Grabbed all the 93 ductwork as well including distribution right down to the floor vents, since I wasn't sure about connectivity to my 84 system. Snowflake rocker AC switch.

LOTs of other goodies for my 242 future project to boot. I'll host up some pics later and link them.

FWIW, the dash removal really wasn't that big of a deal.... damned steering wheel was in the way and I had to wrestle around it. Other than being sore as hell from sitting on steel for 8 hours, I'm happy.
 
Is there any way to fit the '93 setup with the '75-80 dash? I'm getting ready to reassemble my car and have been tempted to grab a '93 heater box with room to add AC if I need it later, but want to keep my original dash.
 
Nice to meet you DET17. Glad we were able to grab some parts off that 93' we both could use.

it's a shame that car was there, super clean, straight car all original down to the factory cassette player. I played around with my 93 'donor car' and found a chewed up wire that gives + to the compressor clutch, must have slung a belt and cut the wire. Regardless, it's good to have a spare compressor, being a 93 only deal. I just have to work up the energy to start tearing it down, hopefully before it gets to hot out.
 
DET17 said:
Well I hit paydirt yesterday at the ATL PnP South (and met a fellow TBer Matt86 as we were cannibalizing the same 93).

Extracted the ENTIRE HVAC system from the 100k mile 93 240 (R134a stickers factory).... except the compressor which Matt needed. 1year only condenser & fan, complete line set & dryer/filter, and the legendary 91-93 HV blower with evaporator. Grabbed all the 93 ductwork as well including distribution right down to the floor vents, since I wasn't sure about connectivity to my 84 system. Snowflake rocker AC switch.

LOTs of other goodies for my 242 future project to boot. I'll host up some pics later and link them.

FWIW, the dash removal really wasn't that big of a deal.... damned steering wheel was in the way and I had to wrestle around it. Other than being sore as hell from sitting on steel for 8 hours, I'm happy.
Click to expand...

If you didn't grab the harness pig tail that the snowflake switch was plugged into, go back and get it. That harness is about a foot long and has the AC relay incorporated into it. Cut the mating connector out of the dash harness at the same time and you will have everything to wire up your AC. There is also a harness in the engine bay you need that goes to the pressure switch and compressor.
 
2manyturbos said:
If you didn't grab the harness pig tail that the snowflake switch was plugged into, go back and get it. That harness is about a foot long and has the AC relay incorporated into it. Cut the mating connector out of the dash harness at the same time and you will have everything to wire up your AC. There is also a harness in the engine bay you need that goes to the pressure switch and compressor.
Click to expand...

Sadly, someone before me disconnected all the switches/relays prior to my arrival. The snowflake switch was still in the fascia but nothing attached. I did pull both AC line sensor harnesses under hood, as far as possible. Is the wiring & AC relay a 93 only, or other years as well?
 
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