Getting AC to work after the 3.4 swap

**Elvota** · 05-02-2008, 11:02 AM

My 4Runner had factory AC... I just need to figure out how to hook it up to the 3.4.

Here is what I think I want to do:

Run the 3.4 compressor with the 3.0 top plate so lines from the '90 will work. I'd like to run R134 throughout the system, thus wanting to run the more modern compressor.

I assume I will also need to change out the rest of the O-rings to something that will work with R134?

I assume I'll need a new dryer... but what else? The system has been "open" as I had a line break some time ago before the swap. I have had all the opening capped, and plan to get a new '90 line to get everything connected again.

I am not sure about the wiring. I have the factory switch, and the wire marked on the 3.4 harness... but are they compatible? My concern is there might be some change like with the oil pressure sender or tach between the 3.0 and the 3.4.

Any ideas or additional comments would be greatly appreciated.

mt_goat · 05-02-2008, 03:21 PM

The shop that did my AC service converted the fittings over to R134 fittings, I can't remember if they changed any O-rings then, but it had a leak afterwards and I think they did change at least one O-ring at that time. They also added oil to the compressor...my memory is fading...here's the post I did at the time:
http://www.yotatech.com/1015770-post315.html

The AC topic started on page 10 on my swap thread:
http://www.yotatech.com/f160/3-4-swa...5/index10.html

But ORS did the wiring for it as part of their wiring harness so I can't help there.

Oh yeah I replaced the receiver/dryer too, and before I took the old compressor out I had a friend at the dealer vacumm/discharge all the old R-12 out. It's best to replace the dryer right before you recharge and pull a vac on the system before recharging.

Its been over a year now since the R134 conversion and no more leaks and it blows good and cold.

tallboy · 05-02-2008, 04:56 PM

If you need a vacuum pump and gauges let me know. You can borrow or I could help you.

**Elvota** · 05-02-2008, 05:27 PM

Quote:

Originally Posted by mt_goat

The shop that did my AC service converted the fittings over to R134 fittings

Oh right... the R12 and R134 fittings are different. So if I want to retain the original R12 lines I'd need to adapt them to the R-12, correct?

Quote:

Originally Posted by mt_goat

I can't remember if they changed any O-rings then, but it had a leak afterwards and I think they did change at least one O-ring at that time.

I have heard sometimes R12 O-rings hold up. I have to learn where all the O-Rings are and see how I can replace them.

Quote:

Originally Posted by mt_goat

ORS did the wiring for it as part of their wiring harness so I can't help there.

I'll have to figure that one out a bit more then.

Quote:

Originally Posted by mt_goat

Oh yeah I replaced the receiver/dryer too, and before I took the old compressor out I had a friend at the dealer vacumm/discharge all the old R-12 out. It's best to replace the dryer right before you recharge and pull a vac on the system before recharging.

Do you think using the new R134 compressor I'd need to discharge/ vacumm out the unit? I'll be sure to install the dryer as a last step before charge.

Quote:

Originally Posted by mt_goat

Its been over a year now since the R134 conversion and no more leaks and it blows good and cold.

That's good news for sure. I haven't had AC since I broka a line alomost on day one when I purchased the vehicle. Mind you, I wasn't that bothered as the AC made the 3.0 even more gutless. But now I am looking forward to possibly getting this fixed before the 100 plus days start here in AZ.

**Elvota** · 05-02-2008, 05:39 PM

Quote:

Originally Posted by tallboy

If you need a vacuum pump and gauges let me know. You can borrow or I could help you.

Have you any AC experience? I wouldn't mind a hand once I get the parts I need. I am clueless when it comes to the R134 charge process.

mt_goat · 05-02-2008, 06:30 PM

Quote:

Originally Posted by Elvota

Do you think using the new R134 compressor I'd need to discharge/ vacumm out the unit?

Maybe I wasn't clear, I am also using a 3.4 compressor (R134).

screamer76 · 06-22-2008, 10:43 PM

hey elvota, have you made any progress with this? i'm particularly interested in your wiring solution. can't go much longer without it and i finally have all the parts.

nv4runner · 06-22-2008, 10:58 PM

One of the teachers from the community college (teaches A/C) and I are in the process of converting my R12 system to R134a. All he told me to get was the R12 to R134a fittings, which cost me about $6 each (need a high side and a low side). When we charge it we're going to put in 2 ounces of some high grade A/C oil that is designed for this kind of thing. My system's been open for quite a long time so there's no more R12 left in it so don't have to worry about having an R12 and R134a compatible oil. He hasn't said anything about O rings as it was my schrader valves that caused the leak. He also hasn't expressed much concern about moisture collecting in the dryer, but it wouldn't hurt to change it out.

On my 4runner the max amount of R12 is something like 1.9lbs, or was that the chevy we worked on that day, and a conversion table indicates that we should put in around 1.2 lbs of R134a. I'll have more exact numbers when we actually do it.

To make the A/C system perform like stock after converting you must install a larger condenser (in front of radiator) and a larger evaporator (in the cab). If you don't the A/C won't get quite as cold as it did from the factory, but it still works.

Hope this helps.

**Elvota** · 06-23-2008, 01:30 PM

Quote:

Originally Posted by screamer76

hey elvota, have you made any progress with this? i'm particularly interested in your wiring solution. can't go much longer without it and i finally have all the parts.

I haven't really gotten any further. I connected the lines and installed the compressor. Bought a new drier and have the grill off... but that's it.

I only have to drive about 1/2 hour during the heat of the day and haven't had AC for maybe 5 years now, so I am just used to it.

I will add some info to my thread when I make some forward progress.

**Lysmachia** · 06-23-2008, 04:23 PM

Quote:

Originally Posted by mt_goat

But ORS did the wiring for it as part of their wiring harness so I can't help there.

And you keep telling me to save Money Steve!!

Ok back to our regulary scheduled trouble shoot! (I swear a 3.4 is in Tippy's futurte. I moved the engine like 4 feet the other day. Does that count??)

BTW steve got a really great friend that has done 5 swaps now and is involed with ORS so if ya still are stuck I'll pull in the beer favors (Meaning I now owe him a keg) and call him for ya

)

**Elvota** · 06-24-2008, 09:21 AM

Quote:

Originally Posted by Lysmachia

And you keep telling me to save Money Steve!!

I just have to put some time in to the figurin'.... just haven't had the motivation. One would think that 100 plus days would be all I need to get this figured out, but I just haven't had AC for so long I have trouble bothering now.

Usually, by the time I get fed up and swear to myself to get my AC sorted out... the temps cool off again and I just wait until next year.

odonekanobe · 07-07-2008, 08:36 PM

So I am in the process of collecting the parts I need to do this. I have a old 3.0 compressor on the way for the connections, and a 3.4 compressor on the way to bolt up. My big question is electrical. What all do I have to do to get it to work. I have heard that the "a/c amplifier" is different polarity between the years. I have also heard I can pull the box/brain from behind the glove box and swap in a newer one.

Does anyone have any experience with this?

streetable · 10-01-2008, 11:52 PM

I've got my 90 4runner running great with my 3.4. Did it all myself including wiring, but my A/C isn't done yet. I'm in Sacramento and this is highly unacceptable. I kept the 3.0 compressor and all other A/C parts. I need help with the wiring for the A/C. If someone can please let me in on the secret wiring details for the A/C. I'm set up with a 96 3.4. HELP

4000 miles since July 08. Waiting to buy SC. Kick *ss seabass

**Elvota** · 10-02-2008, 12:10 AM

Quote:

Originally Posted by streetable

I'm in Sacramento and this is highly unacceptable.

Poor little fellow. What you got, 88 degree days?

Just giving you a hard time. If I can make it though a couple AZ summers complaining every day about my AC not working then I guess we all can.

Quote:

Originally Posted by streetable

I need help with the wiring for the A/C. If someone can please let me in on the secret wiring details for the A/C. I'm set up with a 96 3.4. HELP.

Well, I still haven't really figured it out. Mind you, I haven't spent that much time on it either. I got the physical components all hooked back up... just no wiring. Now that it's cooling off, it will have to wait another 6 months.

By the way... aren't those 3.4's just to much fun to drive?

streetable · 10-02-2008, 12:35 AM

88 more like 108, but who's keeping track. I refuse to wait till next summer to try to figure this out. Call me stubborn. If anyone can help I'd appreciate it. In the meantime I will keep looking at these wire diagrams with cross eyes trying to decipher the secret code. ha-ha

mt_goat · 10-02-2008, 05:54 AM

Quote:

Originally Posted by streetable

88 more like 108, but who's keeping track. I refuse to wait till next summer to try to figure this out. Call me stubborn. If anyone can help I'd appreciate it. In the meantime I will keep looking at these wire diagrams with cross eyes trying to decipher the secret code. ha-ha

Was your 3.0 an auto tranny? Because the 3.0 auto had an AC cutoff switch in case the engine coolant got too hot it would shut off the AC. The 3.4 ECU doesn't provide a signal to the AC to turn on that switch. It was only on the autos though. My AC cutoff switch has been bypassed.

streetable · 10-02-2008, 07:08 PM

Mt Goat--I've got a manual trans. So thats not going to be the problem.

Chris

05-02-2008, 11:02 AM	#1 (permalink)
Elvota Super Moderator Staff Join Date: Jun 2005 Location: Phx, AZ Posts: 3,442	Getting AC to work after the 3.4 swap My 4Runner had factory AC... I just need to figure out how to hook it up to the 3.4. Here is what I think I want to do: Run the 3.4 compressor with the 3.0 top plate so lines from the '90 will work. I'd like to run R134 throughout the system, thus wanting to run the more modern compressor. I assume I will also need to change out the rest of the O-rings to something that will work with R134? I assume I'll need a new dryer... but what else? The system has been "open" as I had a line break some time ago before the swap. I have had all the opening capped, and plan to get a new '90 line to get everything connected again. I am not sure about the wiring. I have the factory switch, and the wire marked on the 3.4 harness... but are they compatible? My concern is there might be some change like with the oil pressure sender or tach between the 3.0 and the 3.4. Any ideas or additional comments would be greatly appreciated. __________________ ================ 1990 4Runner \| V6 3.4 \| 5spd \| 240 someoddthousand miles \| SR5 \| SAS \| RLS \| 35's \| ARB \| TJM \| 217 to 1 \| W8000 - four wheels \| three sticks \| two hands \| one trail - RIGITY DIGITY

05-02-2008, 03:21 PM	#2 (permalink)
mt_goat Contributing Member Join Date: Nov 2002 Location: Oklahoma State Posts: 7,424	The shop that did my AC service converted the fittings over to R134 fittings, I can't remember if they changed any O-rings then, but it had a leak afterwards and I think they did change at least one O-ring at that time. They also added oil to the compressor...my memory is fading...here's the post I did at the time: http://www.yotatech.com/1015770-post315.html The AC topic started on page 10 on my swap thread: http://www.yotatech.com/f160/3-4-swa...5/index10.html But ORS did the wiring for it as part of their wiring harness so I can't help there. Oh yeah I replaced the receiver/dryer too, and before I took the old compressor out I had a friend at the dealer vacumm/discharge all the old R-12 out. It's best to replace the dryer right before you recharge and pull a vac on the system before recharging. Its been over a year now since the R134 conversion and no more leaks and it blows good and cold. __________________ Dale "America is in a hole and it's getting deeper every day. We import 70% of our oil at a cost of $700 billion a year - four times the annual cost of the Iraq war." T. Boone Pickens Check out the plan: http://www.pickensplan.com/index.php and http://www.cngnow.com/EN-US/Pages/default.aspx Last edited by mt_goat : 05-02-2008 at 03:31 PM.

05-02-2008, 04:56 PM	#3 (permalink)
tallboy Registered User Join Date: Jan 2004 Location: Phoenix Posts: 130	Good Luck If you need a vacuum pump and gauges let me know. You can borrow or I could help you. __________________ Dana 44 front ,v-6 3rd member, 56" long springs 4:88 gears ARB's front and rear.

06-22-2008, 10:58 PM	#8 (permalink)
nv4runner Registered User Join Date: Dec 2007 Location: Reno, NV Posts: 89	One of the teachers from the community college (teaches A/C) and I are in the process of converting my R12 system to R134a. All he told me to get was the R12 to R134a fittings, which cost me about $6 each (need a high side and a low side). When we charge it we're going to put in 2 ounces of some high grade A/C oil that is designed for this kind of thing. My system's been open for quite a long time so there's no more R12 left in it so don't have to worry about having an R12 and R134a compatible oil. He hasn't said anything about O rings as it was my schrader valves that caused the leak. He also hasn't expressed much concern about moisture collecting in the dryer, but it wouldn't hurt to change it out. On my 4runner the max amount of R12 is something like 1.9lbs, or was that the chevy we worked on that day, and a conversion table indicates that we should put in around 1.2 lbs of R134a. I'll have more exact numbers when we actually do it. To make the A/C system perform like stock after converting you must install a larger condenser (in front of radiator) and a larger evaporator (in the cab). If you don't the A/C won't get quite as cold as it did from the factory, but it still works. Hope this helps. __________________ 92 4Runner 5 spd V6 31X10.5X15LT

10-01-2008, 11:52 PM	#13 (permalink)
streetable Registered User Join Date: Jun 2008 Location: Sacramento Posts: 3	3.4 A/C swap I've got my 90 4runner running great with my 3.4. Did it all myself including wiring, but my A/C isn't done yet. I'm in Sacramento and this is highly unacceptable. I kept the 3.0 compressor and all other A/C parts. I need help with the wiring for the A/C. If someone can please let me in on the secret wiring details for the A/C. I'm set up with a 96 3.4. HELP 4000 miles since July 08. Waiting to buy SC. Kick *ss seabass

06-22-2008, 10:43 PM	#7 (permalink)
screamer76 Registered User Join Date: Nov 2007 Location: tucson,az Posts: 201	hey elvota, have you made any progress with this? i'm particularly interested in your wiring solution. can't go much longer without it and i finally have all the parts.

07-07-2008, 08:36 PM	#12 (permalink)
odonekanobe Registered User Join Date: Jul 2007 Posts: 27	So I am in the process of collecting the parts I need to do this. I have a old 3.0 compressor on the way for the connections, and a 3.4 compressor on the way to bolt up. My big question is electrical. What all do I have to do to get it to work. I have heard that the "a/c amplifier" is different polarity between the years. I have also heard I can pull the box/brain from behind the glove box and swap in a newer one. Does anyone have any experience with this?

10-02-2008, 12:35 AM	#15 (permalink)
streetable Registered User Join Date: Jun 2008 Location: Sacramento Posts: 3	88 more like 108, but who's keeping track. I refuse to wait till next summer to try to figure this out. Call me stubborn. If anyone can help I'd appreciate it. In the meantime I will keep looking at these wire diagrams with cross eyes trying to decipher the secret code. ha-ha

10-02-2008, 07:08 PM	#17 (permalink)
streetable Registered User Join Date: Jun 2008 Location: Sacramento Posts: 3	Mt Goat--I've got a manual trans. So thats not going to be the problem. Chris

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode