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Insulating A/C lines under the hood

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by jacksprat1599, Jul 20, 2004.

  1. jacksprat1599

    jacksprat1599 Registered Member

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    My 89 burb can't keep me cool once the mercury hits 95.I was looking at an 01 HD truck the other day that appeared to have some thin aluminum mat type insulation on the A/C dryer.Could this be done to my truck to make it a little cooler inside and how obout insulating any a/c lines under the hood(the cold ones only) to help out.Any reason this could be a bad idea?
     
  2. jacksprat1599

    jacksprat1599 Registered Member

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  3. 2Dogs

    2Dogs 1/2 ton status Premium Member

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    I bet you will find ducting unplugged or seals completely gone (under dash) if you tear into it. Should keep you cool....

    But yes to all your questions - you would make the system more efficient but is the cost worth the return. Find out if there is something obviously wrong first.
     
  4. BobK

    BobK 1/2 ton status

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    All the "cooling " happens in the evap. core which is covered with the plastic houseing.
    Insulating the lines will do nothing for cooling.They just carry the refridgerant.

    If you want to insulate a line insulate the line going to the inlet of the evap. core.That usually the lower line.
     
  5. BlazerGuy

    BlazerGuy 3/4 ton status

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  6. BobK

    BobK 1/2 ton status

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    Turbo's put out a crap load of heat though.I could see insulating lines for heat protection.
    I guess it could heat up the refridgerant in the lines enough to effect the A/C performance
     
  7. jacksprat1599

    jacksprat1599 Registered Member

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    thanks fellas,I tried insulating the lines that were cold to the touch when ac is operating as well as the dryer.the air coming out of the vents is about forty degrees when going down the highway but it only gets down to about 60 degrees in stop and go traffic.I mostly wanted to see if I would do damage to the dryer by doing this as I don't know jack about ac systems.From reading the other recent post about ac systems I'm thinking my problem is more airflow across the condenser since it cools well at 60 mph. Would an electric fan help out at these slow around town speeds?
     
  8. dyeager535

    dyeager535 1 ton status Premium Member

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    What kind of speed do you need to get cold AC?

    I figured out on my truck with the new engine, electric fans that don't run unless engine hits 220*, new 3 core radiator, and about 33% antifreeze to water mix, about 15MPH with very little load on the engine (flat ground, holding constant speed), and right around 80* ambient air temp, I don't need fans.

    I would suspect with an auto trans and AC the speed required to get the same cooling would be increased by quite a bit, guessing 25MPH or so.

    There are still a bunch of variables in your situation though, and I doubt anyone KNOWS the answer. However, in factory GM electric fan applications (Camaro's for instance) the fan(s) come on regardless of engine temperature if AC is requested. With a clutched fan, this isn't possible, since it only engages based on temperature.

    So even though the engine temp won't change with the electric fan on (the thermostat governs the engine temp) the air movement IS increased, which will result in (theoretically) cooler AC.

    Obviously you need a fairly good sized electric fan to expect to cool a SBC in town, especially if replacing the clutch fan. I'd run only one or the other, although a pusher fan MIGHT help a little bit, one large fan (or two) will just cool better, and if going for maximum AC performance, would be the way to go.
     
  9. HarryH3

    HarryH3 1 ton status Author

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    Re: Insulating A/C lines under the hood *DELETED*

    Post deleted by HarryH3
     
  10. dyeager535

    dyeager535 1 ton status Premium Member

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    [ QUOTE ]
    Even with a clutched fan, the fan is still rotating slightly when disengaged. However, the AC condensor sheds a tremendous amount of heat! When idling in traffic with the AC running, that heat will be flowing across the fan clutch and it should soon engage, to draw even more air across the radiator/condensor. I've noticed that it only takes a short time for the fan clutch to engage on our '94 Sub with dual AC. It also gets oppressively HOT under the hood of that rig when the AC has been running.

    [/ QUOTE ]

    Definitely true. Perhaps checking the fan clutch out is a good idea. It could be that it is not working optimally, and not locking in at as low a temp as it should.

    On the TBI trucks, is idle kicked up when AC is requested? I'd have to have two of these trucks side by side to see which is more effective. I know my electrics move a lot of air, but without actual flow numbers, it's pretty tough to get a good estimate of which fan moves more air at idle.

    I personally think the electric has the clutch fan beat at idle, but only if the idle stays constant with the clutch fan/AC setup.
     
  11. jacksprat1599

    jacksprat1599 Registered Member

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    thanks for the response. I also have an engine oil cooler and trans fluid cooler in front of the condenser so I know the deck is already stacked against me.Who makes a good electric pusher fan that I could try in tandom with the belt driven fan and how much cfm would I need.
     
  12. jarheadk5

    jarheadk5 1/2 ton status

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    The idle RPM isn't bumped up, but the computer does actively compensate for the AC compressor kicking on.
    i.e. Compressor kicks on, RPM dips for a brief second, computer feeds gas, RPM comes back up a little over normal for a couple seconds, then settles back down to normal idle.

    At least that's the way my cousin's '87 K5 is.
     
  13. tx_sub

    tx_sub 1/2 ton status

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    another thing i've heard of doing is putting a ball type valve in the heater hose lines. even if the heat is off, fluid still flows some across that heat exchanger. this should reduce vent temperatures some.

    just remember to open it when it gets cool. i'd also open it ever so often so it doesn't corrode in the exchanger.
     
  14. dyeager535

    dyeager535 1 ton status Premium Member

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    I haven't really heard much about pusher fans, except they seem to be less efficient. I don't think running one in conjunction with the stock fan is really that good of an idea...the stock shroud would "block" airflow..besides, whichever fan pulls more air I would assume would be "blocking" the other one.

    Typically if airflow through the radiator is faster than an electric can handle, the electric just turns faster. However, trying to push or pull air through a fan with another fan just doesn't sound effective.

    If you were only looking to cool something that wasn't seeing much airflow anyways (like a PS cooler on a framerail) another fan could be ok. But I think the best idea is just move more air with a single fan.
     
  15. K5 NUTT

    K5 NUTT 1/2 ton status

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    Insulating the lines and the accumulator is a good idea...you'll notice years back gm did this starting with there vans and nowa days everything....

    DW
     
  16. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    It's coverted to R134 isn't it? My 88 is and it SUCKS. Going down the road is ok but I keep gettign into problems with head presure and it has to cycle. I actually had to much freon for a while and it would lock up the compressor and slip the belt. But put a gage on it and dropped it. This was a pro job done before I bought it and they over charged.
    I have a very minor leak and it will make the summber but by next year it will need a recharge. I will go with variable orifice tube and see how it does and fix the leak.
    I plan to insulate the lines as well.
    on 3/4 ton 454 truck the came FACTORY with AUX electric cooling fan. I'm going to put a Relay on it and see if it improves AC in traffic.
     
  17. K5 NUTT

    K5 NUTT 1/2 ton status

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    Grimey...don't bother with that variable rate orifice tube...went thru that hassle on a 96 big block burb...didn't do squat...try the blue ford orifice...open the hood of a 95 up gm van or p/u...the accumulator has a neoprene boot to help keep it cool...and a vacum operated water valve works great also...tee into your fresh air door under the cowl (max air or recirc)....and run that fan! Plus have you taken the front end apart and blown-hosed it out since ownership? You'd be surprised!

    So...how ya feelin these days...been wonderin after the big scare you gave me...us!

    Havin a nice summer here in co. Made it out twice to fish sofar...caught some german browns and rainbows the last trip out...headin down to durango thursday to ride the train thru the mountains to silverton....oh ya..back in the army reserve and moma is pregnant again...hopin for a boy this time....lol.

    DW
     
  18. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Well congrats! Yeah keep us informed on that.

    Health I doing pretty good. I'm actually probably in better shape then I was 10 years ago. Don't smoke anymore at all. /forums/images/graemlins/thumb.gif

    Still planning on making it out that way one day. Been working on the camper trying to get it down and make a good trip.

    Job I been doing for the past 11 years is about to be gone but lined up another with the same company so I don't loose my bennies and time served.
     

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