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R134 STINKS! A/C tricks to make it work.

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Grim-Reaper, Jul 21, 2003.

  1. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Ok I'm going to do a few things to get my convertets A/C to work a little better. It just takes to long to cool things down after sitting in the sun all day and it's pitiful when caught in traffic.

    Thought I would toss out a few things and see if folks have some stuff to add.

    First thing I'm going to do is insulate all the cold lines. K5NUTT mentioned that in a post as helping. Makes sense to keep it as cool as possible before it gets to the blower box.

    This is on my 454 dual Air burb. I figure I'm loosing a LOT of cooling on 30+ feet of lines on that booger. On the rear circuit I will insulate the return rout as well . My theroy is it's picking up heat on both lines. That's making the A/C have to work harder. Not just to the excahnge in the cabin but it's probably also causing the preasure to rise in the system making it harder for the engine to pump it.

    Ok now give me a few ideas of products to use. It has to live under the truck. It has to be impervious to moisture. The cold lines will sweat not to mention what will be kicked up off the road. Right now I'm using either the balck foam rubber stuff you can pick up at most home stores or the stuff that is more of a plastic and less flexible. I think the plastic stuff may have a better R value. Not sure what one will hold up better. I know tha black stuff don't do well when exposed to oils. Also doesn't age well but I don't know if the other stuff does any better.

    Under the hood I have extra trouble. With the dual Air I have lines fairly close to the exhaust manifold. Anybody have an idea of what to use that isn't going to melt from 500degrees of heat coming off the exhaust manifolds?

    How about what to use on the drier canister?

    Also I have heard that often a electric pusher fan helps. My truck has one factory already but I need to fine tune it. No shoude so I know a little bit of aluminum I can probably get 25-30 % better flow out of it.

    Come on! lets hear ideas. Folks are always complaining about how bad the A/C does after going to 134. Lets try a few tricks and see what we can come up with.
     
  2. Bubba Ray Boudreaux

    Bubba Ray Boudreaux 1 ton status

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    Here's something that scratched my head when I was picking up my Ford fans a few months ago. There was one car that had a pusher on it, maybe all of 8" if that in front of the condenser. Maybe hitting the junkyards and try to find something similiar.
     
  3. HarryH3

    HarryH3 1 ton status Author

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    Our '94 Suburban with factory 134a has a black foam insulating cover around the accumulator/drier. You should be able to nab one of those for about nothing at a junkyard.

    I'm also considering insulating the lines to the rear a/c, as it didn't blow anywhere near as cold as the front a/c on a trip to Hell, er, Texas last week. /forums/images/graemlins/eek.gif
     
  4. k5blazerus

    k5blazerus 1/2 ton status

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    Take it to a a/c shop and see if your 134-a freon is low.
     
  5. ZooMad75

    ZooMad75 1/2 ton status Premium Member GMOTM Winner

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    If you want some tough insulating matieral, go over to www.koolmat.com They have a material made of silicon and fiberglass that is good up to 500 degrees and impervious to grease, fluids and the like. They also have some NASA grade heat shields good up to 2500 degrees.

    I've got a starter sheild from them made of the koolmat material, wraps around the starter with a 3000 degree stainless steel tie strap. no more solonoid problems. High quality stuff. The lady that runs it is very helpful and could lend a hand in helping insulate the lines.

    I would also suggest a hot water shut off valve on each supply line to the front and rear heater cores. in the summer you are not going to need the heat.
     
  6. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    [ QUOTE ]
    If you want some tough insulating matieral, go over to www.koolmat.com They have a material made of silicon and fiberglass that is good up to 500 degrees and impervious to grease, fluids and the like. They also have some NASA grade heat shields good up to 2500 degrees.

    I've got a starter sheild from them made of the koolmat material, wraps around the starter with a 3000 degree stainless steel tie strap. no more solonoid problems. High quality stuff. The lady that runs it is very helpful and could lend a hand in helping insulate the lines.

    I would also suggest a hot water shut off valve on each supply line to the front and rear heater cores. in the summer you are not going to need the heat.

    [/ QUOTE ]

    Ok! that stuff looks like the ticket near the exhaust manifold.

    My truck doesn't have rear heat so not a problem back there.

    My issue with cutting off that circuit is some stuff I picked up somewhere along the way. GM didn't put a cut off valve in there because they use it to pre heat the radiator. The idea being that if they get some temp in there before the Thermostat opens you wont have the thermostat slam shut when it gets hit by that cold coolant from the radiator. It also helps prevent 30degree water from just dumping into the engine thats already up to 150degrees (yeah not a problem in the summer). It does make the heat ups cycle even out year round.

    Other thing I have heard is it helps equalize pressure on both side of the Thermostat when it's closed. This helps prevent presure on one side holding it closed.


    Think about it this way. If you block that line all that pressure is against the side the thermostat opens on ( it opens down into the intake). I may look into setting up a valve system so I can by pass the heater core but stil have the loop from the intake to the radiator. That would keep things in order.
     
  7. ZooMad75

    ZooMad75 1/2 ton status Premium Member GMOTM Winner

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    I know what you mean about the t-stat. I only mention it as I've seen it work first hand. My buddy has a 78 K10 that he has converted to 134a. We ran it in the heat of Pueblo, CO (lately more like Phoenix!) and it was cool but not frosty. He put the hot water valve on it and it was nice and chilly the next time we went out in it. Its a little different since its not his daily driver, but his 454 hasnt the slightest bit of cooling problem. Then again, big blocks do have the bypass hose from the intake to the waterpump. When its time for winter wheeling, open the valve.

    While GM may have not used water valves recently, my old 78 malibu had a vaccum controled hot water valve used with the a/c system.
     
  8. K5 NUTT

    K5 NUTT 1/2 ton status

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    Harry's on the trail with the neoprene boot for the accumulator....motorhomes use some sort of sleeve thats some sort of heat sleeve inside and a metalized covering outside....next time you see a mid 80's ford p/u look at the suction line that runs behind the motor...(hint)...and i'm sorry but the vacum operated heater valve in max cool is worth 10 degree's...another thought...check out an assortment of ford orifice tubes...diff colors equal orifice tube diameter....try a size smaller than what gm installs....or try a smart vov....haven't had the chance to try one but people who do swear by them...insulate the outside of the evap box...engine heat can boil the refridgerant in the suction lines and accumulator....also the newest deal on the market is a new style condensor...a serpintine style setup....aluminum and superior to the old style...you'll have to fab it in a modify your lines but it the real deal...

    DW
     
  9. Blue85

    Blue85 Troll Premium Member

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    I installed dual electric fans and sealed off the gap between the condensor and the radiator. Made a big difference, especially at standstill. Yes, the max flow of the stock fan is probably greater, but at idle, it's flow is not so great. The electrics give full draw regardless of engine speed.

    Make sure you run the right orifice tube. R134-a should use a slightly smaller one than R-12 since the molecules are smaller. One size smaller than stock should be right. I think this size was common in Fords, but any A/C shop or parts store will have it for a couple of bucks.

    Better yet, get one of these and get the best of both worlds (large orifice on the highway, small one at idle) VOV
     
  10. greybeard

    greybeard Registered Member

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    Don't forget an R-134 pressure cycling switch! I've been running the K-5 for a week now with an A/C thermometer in the vent. I've noticed a 10 - 15 degree increase in the temp depending on how hot it is outside and how long I sit at the light. I need to check into a pusher fan.
     
  11. Blue85

    Blue85 Troll Premium Member

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    [ QUOTE ]
    Don't forget an R-134 pressure cycling switch!

    [/ QUOTE ] That is so true. In fact, it's a legal requirement in some areas for the conversion.

    For a little while, I had both of my fans on one relay. The socket had a bad crimp, which melted the leg out of the relay and cut the fans off. It was 95 degrees and I was in a drive-thru lane. The compressor blow-off valve vented and made a cloud come out from under the hood. /forums/images/graemlins/eek.gif /forums/images/graemlins/eek.gif With a new relay it blew cold again, so it couldn't have vented too much, but still, this little switch could save your whole A/C system.

    I thought I'd mention too that I used to run the clutch fan with an electric pusher covering 1/2 of the condensor and I'm not sure it did very much.
     
  12. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    [ QUOTE ]
    Don't forget an R-134 pressure cycling switch! I've been running the K-5 for a week now with an A/C thermometer in the vent. I've noticed a 10 - 15 degree increase in the temp depending on how hot it is outside and how long I sit at the light. I need to check into a pusher fan.

    [/ QUOTE ]


    Never heard of it. THis was converted by a respected shop before I owned it. I have managed to lock up the compressor already. I was reving up the engine trying to get it to overheat. let it get back to idle and then hit the gas again and the belt started screaming. I killed the engine and jumped out and tried to turn the compressor by hand. To much pressure. I could hear the pressure bleeding off through the orifice tube. 10 seconds later I tried to trun the compressor and had no problems.
    Hmmmmmm Let me make a call.
     
  13. Blue85

    Blue85 Troll Premium Member

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    Weird. It doesn't sound like lock-up to me, just a loose belt. When the system has pressure I don't think you can ever turn the compressor by hand. And the pressure leaking through the orifice tube, you can always hear that when you first shut the system down. If you indeed exceed the safe pressure, you will either pop the blow-off valve or rupture something.
     
  14. Bullet

    Bullet 1/2 ton status

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    [ QUOTE ]
    Hell, er, Texas last week. /forums/images/graemlins/eek.gif

    [/ QUOTE ]

    Hey, I haven't had A/C in the Jimmy for about 2 yrs now and it got over 100* today!

    But I can't say much since I am getting converted the A/C fixed tommorow /forums/images/graemlins/smirk.gif
     
  15. greybeard

    greybeard Registered Member

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    The pressure cycling switch controls the on and off operation of the compressor. It monitors the low pressure side of the system. It's mounted on the left side of the accumulator. It is my understanding that R-134 systems run at a lower pressure then R-12. I'm no expert but I've been told that if you don't replace the pressure switch, the system will not cool as well. Maybe I'll put the R-12 one back on and see if there is any difference!
     
  16. Derf00

    Derf00 1/2 ton status

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    Wrong jr. you are getting your system reflled with the good stuff, R12. It helps to have friends in the A/C business. /forums/images/graemlins/grin.gif
     
  17. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    [ QUOTE ]
    The pressure cycling switch controls the on and off operation of the compressor. It monitors the low pressure side of the system. It's mounted on the left side of the accumulator. It is my understanding that R-134 systems run at a lower pressure then R-12. I'm no expert but I've been told that if you don't replace the pressure switch, the system will not cool as well. Maybe I'll put the R-12 one back on and see if there is any difference!

    [/ QUOTE ]

    Are you talking about the switch on the drier or sometimes on the line right next to it? I always thought that was a low pressure cut off switch. Didn't relize it would also cut off the compressor when it got over a certain pressure.
     
  18. Bullet

    Bullet 1/2 ton status

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    [ QUOTE ]
    Wrong jr. you are getting your system reflled with the good stuff, R12. It helps to have friends in the A/C business. /forums/images/graemlins/grin.gif

    [/ QUOTE ]

    Is the only thing you do is look at everysingle one of my post? /forums/images/graemlins/rotfl.gif
     
  19. K5 NUTT

    K5 NUTT 1/2 ton status

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    Some of the earlier low psi switches were adjustable...

    Most conversion kits and or add on systems all require the use of a high psi cut out switch so the relief valve doesn't allow freon to vent to the atmosphere...

    DW
     
  20. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    [ QUOTE ]
    Some of the earlier low psi switches were adjustable...

    Most conversion kits and or add on systems all require the use of a high psi cut out switch so the relief valve doesn't allow freon to vent to the atmosphere...

    DW

    [/ QUOTE ]
    Ok so same switch but two functions. Now how the heck do I tell if I got the right one. SHould I go to the shop that did the conversion and start bashing heads?
     

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