73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Interior & Equipment => Heating, Ventilation & Air Conditioning (HVAC) => Topic started by: MrFiveOh on July 11, 2016, 11:47:45 am
-
I have all the required pieced to install 134A A/C from a 1984 C10 in my truck except the condenser, I dont have a condenser currently installed at all. It was recommended I get a parallel flow condenser. I can only find one for a 84-87 model. My question is will a 84-87 Condenser fit/work in a 1974 C10?
Edit: I guess the big question is, Has anyone installed a parallel flow condenser from an 84-87 Square in a 73-74 C10 as part of upgrading the A/C from R12 to 134A?
Thanks
-
Later models condenser mounts on the back side of the radiator support.
1974 mounts in front of the radiator support behind the grill. The high side line routes behind the grill also unlike the later models that run across the top of the radiator area.
If you can find a way to mount it behind the grill and hook up the lines.
Parallel flow is better for R134.
-
Also, you don't have to swap all the parts to use R134. Most of the parts can be flushed and reused. My truck originally had R12, as did all squares with ac and I still have the original condenser and evaporator. Ac blows nice and cold.
-
I understand that, the only thing i had from the old AC setup was the orifice, which is being replaced with new
-
Also, you don't have to swap all the parts to use R134. Most of the parts can be flushed and reused. My truck originally had R12, as did all squares with ac and I still have the original condenser and evaporator. Ac blows nice and cold.
I also have one of those smaller compressors.
-
The R4 will cool with R134a but not as well as the A6 that came on the 1974 or the later HT6 compressors GM used on the late 90's T400 chassis.
The 1984 condenser will not mount in the stock 1974 location. As noted above the 1973 to probably 1980 mounted between the radiator support and the grille. I'd take some measurements and get a condenser that will cover the hole in the rad support fairly well.
Hard lines from any aftermarket condenser will need to be fabbed to run to either stock passthroughs or new holes in the rad support. The parallel flow condenser will be more efficient. Mine will freeze me out of the 76 with a stock 1998 HT compressor on a 1998 6.5L diesel engine.
If you intend to use the R4 Radial compressor you'll need to be sure all the hard components (evaporator, hard lines, and condenser) are absolutely clear of ALL the old compressor oil. The R4 is not forgiving at all of any deficiencies in the charge level or any extra oil floating around in the system in hot climates like Austin, TX.
The 1974 had a Throttling Expansion Valve TXV on the evaporator not an orifice valve.
What are you calling the Orifice? Picture?
Did you get the 1984 evaporator and accumulator? You want to keep the mix N match to a minimum.
-
One more note...
The charge level of whatever refrigerant you want to use will need to be determined by cooling and pressures. You can't interpolate the number of lbs of refrigerant based on what the old R12 system took.
I posted the JungleEddy method for charging an AC system with a non OEM refrigerant on this or one of the other squarebody boards. It works with R134a and the Hydrocarbon refrigerant blends.
-
Hattie: all the parts I have are from an 84, the compressor looks like this..http://m.oreillyauto.com/h5/r/oap/site/c/detail/MRY0/57221/02645.oap?year=1984&make=Chevrolet&model=C10%2BPickup%2BRWD&vi=5000632&ck=Search_A%21s%21C+Compressor_5000632_-1&search=true&keyword=A/C%20Compressor
I sorry for confusion I guess I am mixing the orifice and accumulator it's the silver canister attatched to the box on the passenger side. Mix and match is very minimal. I just need a condensor.
-
My 74 k5 is not TXV. It is an early design brass orifice tube. It uses a temp probe for cycling. Which I have converted to a pressure a switch.
-
Please don't mind me jumping here but I have a question on A/C also. I converted mine a few years ago and it was well worth it. Yet it seems to work the engine hard if you are sitting still. Can this be resolved?
-
My 74 k5 is not TXV. It is an early design brass orifice tube. It uses a temp probe for cycling. Which I have converted to a pressure a switch.
Interesting. My 76 K20 Camper Special was TXV built in Fresno. Wonder how GM determined what system was installed.
Hattie: all the parts I have are from an 84, the compressor looks like this..http://m.oreillyauto.com/h5/r/oap/site/c/detail/MRY0/57221/02645.oap?year=1984&make=Chevrolet&model=C10%2BPickup%2BRWD&vi=5000632&ck=Search_A%21s%21C+Compressor_5000632_-1&search=true&keyword=A/C%20Compressor
I sorry for confusion I guess I am mixing the orifice and accumulator it's the silver canister attatched to the box on the passenger side. Mix and match is very minimal. I just need a condensor.
That's an R4 compressor.
You'll need to replace the accumulator/drier with a new one any time you open the system or change refrigerant. It contains the refrigerant drier desiccant and can trap oil. Don't break the seals to install till you're ready to close the system and vac it down. Try to pick a dry day to close up and vac down or sweep with inert gas. The desiccant loads up with moisture pretty fast.
Sent from my SM-P605V using Tapatalk
-
Interesting. My 76 K20 Camper Special was TXV built in Fresno. Wonder how GM determined what system was installed.
Good question. I know cadillac was still using TXV at the same time period.
Got me interested now. Wonder what the 73 1/2 tons had.
(http://uploads.tapatalk-cdn.com/20160712/12524f719412080fec68776ca31f9988.jpg)
^This is mine with the a newer accumulator.
-
I hope to do this swap this weekend. I will take plenty of pics as i do this, mainly for those who have a 73-74 model that will run into issue i have.
-
I have a new accumulator, Luckily its been pretty dry here in Austin, gonna try to install this weekend. Friend of mine said 84 condenser should work and if all fails he can fab it to work properly and clean.
-
I have a new accumulator, Luckily its been pretty dry here in Austin, gonna try to install this weekend. Friend of mine said 84 condenser should work and if all fails he can fab it to work properly and clean.
Flush the old oil out of the lines, evaporator, & condenser. Too much oil will insulate them and keep the ac from moving heat properly. Drain and refill the R4 compressor with ester oil from a new sealed can. Refrigerant oil is hygroscopic like brake fluid so opened and plastic cans are not a good idea. Ester oil will not get angry about any leftover mineral oil in the compressor.
The service manuals have the compressor and total system oil fill volume. Don't overfill and don't underfill.
The compressor will not hold the full oil charge for the system. You'll need an oil injector to finish the fill from whatever the compressor took to full.
Sent from my SM-P605V using Tapatalk
** EDIT ** I would reccomend using oil with UV dye added. It will allow you to track down any leaks that develop using a black light bulb.
-
Unfortunately I don't have the posts Jungle Eddy has referenced on Vacuum, Flushing, Oil Supply, Leaks etc and I can't find them on the Wayback Machine snapshots of the Aircon Boards.
This is a cut and paste of the original Aircon Boards post including any typos...
Temps and pressures are English units... °F and PSI
This will allow proper charge levels when retrofitting from R12 to R134a, Envirosafe blended hydrocarbon refrigerant, or straight R290 (refrigerant grade clean propane)
--------------
Posted by JungleEddy on September 05, 2001 at 08:17:44: via: or 66.25.151.188
More important stuff.
How to charge an A/C system.
Note: This method will work for any automobile A/C system regardless of refrigerant type. The pressures I list here will only be correct for HC’s.
I have been trying for the past couple of weeks to come up with a “system” that would allow just about anyone to properly charge their A/C system. While this method I have developed is not fool-proof, it yields the closest thing to a perfect charge I have found. I have tested it on three “non A/C” mechanics in the past few days with great success.
First: If you have not read my previous post on vacuum, flushing, oil supply, leaks and fans etc etc, please do so now. You still need a properly assembled system to get proper cooling!
This ENTIRE process makes a few IMPORTANT assumptions!!
1. The ambient air is OVER about 84 degs.
2. You have a set of A/C gauges
3. You do not take shortcuts.
4. You are able to read and comprehend enginsh.
This process will work down to about 80 degs ambient air, but will be MUCH MUCH easier to over charge below 85 degs ambient air!! Relative high side pressures will be lower at 80 degs ambient and pressure drop after wetting the condenser will be less dramatic.
Pull a hard vacuum for a minimum of 15 minutes, 60 minutes is perfect. Static charge the system to about 65 psi while the engine is NOT running.
If you have a low pressure cut out switch on your system you will need to adjust it down to 18-19 psi sometime during this process. Personally, I find it easiest to do this about midway (now) through the charging process. Remove the connector from the switch and turn the adjustor screw about 1 full turn counterclockwise from its factory position. (counterclockwise is less psi, clockwise is more psi, 99% of the time) Start the engine and turn on the A/C, recirc, max fan, and engine at idle. Max fan is important, since it will help keep the evaporator from freezing as you charge. Charge the system slowly (if you have to!) until the compressor stays on fairly continuously at IDLE. The adjustment I illustrated above should give you a cut out psi of 12-18 psi. Watch your low side gauge and SLOWLY increase engine rpm. The low side pressure will drop slowly but substantially because you are still undercharged. Watch it drop from 20+ psi down through the teens and carefully note where the compressor cuts out. Return the engine to idle and pull the connector to the cut out switch and adjust it accordingly. Try this several times until, as the engine is slowly revved the compressor cuts out at about 18-19 psi on the low side.
The Charge:
Bring the engine rpms up to a continuous 1200-1800 rpm. Begin to add refrigerant (if you have to) SLOWLY until you notice that the air at the vents is noticeably cooler than the ambient air, say at about 65-75 degs or so.
At this point grab your garden hose and hose down the condenser; soak it once only. Your pressures will drop dramatically. The high side should drop below 150 and the low side should drop low enough to cycle the compressor, or if the switch is temporarily “jumped” the low side should be well below 20 psi. I prefer at this stage to jump the connector to the pressure switch to keep the compressor running continuously. It makes the process go much faster, but you risk freezing the evaporator. Now, watch the system pressures rise as the water evaporates and the heat in the system and stabilizes and equalizes. This can take a long time if you have a mechanical radiator fan. The point where the pressures remain relatively constant is called equalization.
Here is the key:
(After wetting the condenser) As you are watching the high side pressure rise from 160psi through (potentially) about 205psi the LOW side should REMAIN from 21-24 psi. If the high side never sees 145+psi you are still low on charge as long as the ambient is 85 degs or above. If as the high side needle swings through 160psi the low side is still below 20psi, you will add more refrigerant AFTER wetting the condenser again and dropping the pressures. Keep doing this until the low side remains at 21-24 psi while the high side swings through 160psi and finally settles at equalization (no more rise) Keep the engine rpms constant and wait for equalization (or close) each time before wetting and charging. If you are going carefully and slowly you could see a high side over 225 at equalization BEFORE you reach a full charge. The high side will DROP as you come closer to a full charge. Be aware that if you over-charge, the high side will climb again and never come down.
Note: If the ambient air is above 95 degs, stop watching the low side after the high side climbs past 205 or so. Especially if you have weak fans.
Note: Take your time and wait for equalization and water evaporation off the condenser before adding refrigerant. An overcharge can occur with no more than an extra 1.5 ounces of refrigerant!!
You can double-check your work at any time (and I suggest doing so) by waiting for full equalization and stabilization of pressures. Then, carefully MIST water into the condenser SLOWLY SLOWLY dropping the system pressures and watching for the same readings on the gauges as listed above.
When finished you should have a sweaty return line all the way back to the compressor. When the return line begins to feel chilled over the first portion of its length, you are approaching full charge. Do not forget to reconnect the low pressure cut out switch!
Do not consider your vent temps accurate until the vehicle has been driven for about 10 minutes at moderate highway speeds!!!! Idle low side pressure should not exceed 40 psi (34-38 actual) if everything is working well; good fans etc….
The idea here is that the compressor should NOT cycle when ambient air temps are above 81-84 degs.
Interesting note for tech heads: If you are charging SLOWLY. You will find at first that the high side will be at a higher pressure, after equalization, on a low charge than at a correct charge! Remember, raised heat = expansion and/or pressure.
Why: (basically)
Within a certain range, the pressure in the condenser (high side) is MUCH more affected/determined by the temperature of the refrigerant than its volume.
ALL THINGS BEING EQUAL, the condenser has the ability to lower the temperature of the refrigerant passing through it “X” amount and no more. The compressor, in compressing the refrigerant, heats or raises the temperature of the refrigerant “Y” amount. Lets say the temperature of the refrigerant entering the compressor via the return line is “Z”. So the final temperature “T” of the refrigerant that gets to the orifice/exp valve is: Z+Y-X=T
If we could lower the value of “T” the entire system would work more thermally efficiently and at lower pressures on the high side. So, ALL THINGS BEING EQUAL, you could 1. get a larger condenser and raise your “X” value or 2. lower the value “Z”.
A full charge on an A/C system will not only have enough refrigerant in it to keep the evaporator “chilled”, but JUST ENOUGH that the line leaving the evaporator and returning to the compressor will also have substantially cooled refrigerant in it THUS LOWERING YOUR “Z” value!! Hello!!
Note: Over charging will allow actual condensed refrigerant (liquid) to make it all the way back to the compressor. As we all know, you cannot compress a liquid…boom/screech.
----------------
-
So i got my A/C installed, works great.....Except when I have the A/C full blast at Highway Speeds. A bit of Info before hand.
AC is nice and cold, all speeds work great in town.
Full speed works fine except when Highway speeds - Climbs to "H" fast at highway speeds.
Coolant is new and full.
I have a 6 blade flex fan - Getting replaced with a factory fan with HD fan clutch.
Replaced Coolant Sensor yesterday.
Current 74 radiator is being replaced with a "HD" radiator, just waiting on the panel that goes over the radiator for support.
My coolant gauge doesn't have numbers only "C" to "H" with 1/4, 1/2, and 3/4 marks between.
When the truck is off the needle is at 1/2 when i turn it on it warms up to 3/4 mark and will maintain while driving with A/C at all A/C speeds. I have verified at 3/4 mark I'm only running around 185-190 degrees.
When i am running at highway speeds 60+ and i have A/C on full speed the temp on my gauge continues to rise to the yellow portion right before the "H".
What step s do i need to take to fix this issue along with my gauge reading correctly.
Also prior to A/C being installed my gauge always stopped at 1/4 mark, but i did not realize my coolant was low until recently. Once my A/C was installed and this issue started i checked fluid levels and filled it up, but continue to have an issue.
Thanks.
-
Taller 4 row radiator, standard clutch fan should do you well. You may be fine with the clutch fan. Those flex fans don't pull the air especially when they have some age on them.
-
Taller 4 row radiator, standard clutch fan should do you well. You may be fine with the clutch fan. Those flex fans don't pull the air especially when they have some age on them.
Yes the new radiator is from a BBC alot taller than the one i have now. I have to buy a panel so i can install it since the radiator i have now is alot shorter.
-
You are probably running into a temp sender and gauge mismatch. The needle should be centered at around 190-210°F not at 3/4.
Since the needle is sitting at the 3/4 mark at 190°F temp my guess is the yellow zone is probably only around 230°F. When you reach the yellow part of the sweep it should be pretty close to 250°F.
If it's a 1974 gauge you'll need a 01513321 nailhead sender. The original GM part is obsolete. Replacement nailhead senders don't have the same curve as the original made in 1974 including the parts from AC Delco. Some are worse than others but there really is only one place on the sweep where they are as original.
You can swap in later gauges and matching senders.
-
See Correct temperature sender and connector (http://forum.73-87chevytrucks.com/smforum/index.php?topic=27971.0) in the Forum's Technical Pages. The referenced URL for the sender has changed since the tech thread was created. Thus, on the American Autowire website, search Item Number: 01513321 (http://www.americanautowire.com/shop/temperature-sending-unit-4743) if this new link fails.
-
You are probably running into a temp sender and gauge mismatch. The needle should be centered at around 190-210°F not at 3/4.
Since the needle is sitting at the 3/4 mark at 190°F temp my guess is the yellow zone is probably only around 230°F. When you reach the yellow part of the sweep it should be pretty close to 250°F.
If it's a 1974 gauge you'll need a 01513321 nailhead sender. The original GM part is obsolete. Replacement nailhead senders don't have the same curve as the original made in 1974 including the parts from AC Delco. Some are worse than others but there really is only one place on the sweep where they are as original.
You can swap in later gauges and matching senders.
I did (yesterday) put in a new sender and the correct one as you posted. I got a BWD from Orielly's and with a new clip to slide over it, alot better than the old one that was brittle. Im thinking my gauge may be bad. I have not driven my truck since 8pm sunday, when i got home from work this after noon the gauge was still showing 1/2 mark when off. WHen i turned it on it didnt move until it warms up.
-
Fan shroud installed? Correct rotation fan?
-
You are probably running into a temp sender and gauge mismatch. The needle should be centered at around 190-210°F not at 3/4.
Since the needle is sitting at the 3/4 mark at 190°F temp my guess is the yellow zone is probably only around 230°F. When you reach the yellow part of the sweep it should be pretty close to 250°F.
If it's a 1974 gauge you'll need a 01513321 nailhead sender. The original GM part is obsolete. Replacement nailhead senders don't have the same curve as the original made in 1974 including the parts from AC Delco. Some are worse than others but there really is only one place on the sweep where they are as original.
You can swap in later gauges and matching senders.
I did (yesterday) put in a new sender and the correct one as you posted. I got a BWD from Orielly's and with a new clip to slide over it, alot better than the old one that was brittle. Im thinking my gauge may be bad. I have not driven my truck since 8pm sunday, when i got home from work this after noon the gauge was still showing 1/2 mark when off. WHen i turned it on it didnt move until it warms up.
That doesn't bode well for the gauge. There is a bias resistor on the back of the can that could be bad but it's a devil of a time to find the right one. A new temp gauge should have the correct resistor already.
-
Fan shroud installed? Correct rotation fan?
Yes and yes.
-
Just a follow up. I bought a temp gun and learned after driving for an extended period of time the gauge will move to "H" took my temp gun and I'm running around 180-185. So it appears my gauge is messed up. I installed a new stock fan w/ HD clutch, Temp Sensor. I just got the top panel for the new 4 row BBC radiator, gotta figure out a way to mount it, the holes are there, but i understand there is supposed to be threaded inserts.