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A/C, Alternator, Transmission cooler

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Batchman, Jun 7, 2002.

  1. Batchman

    Batchman Registered Member

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    I believe all of these are releated not sure though. 86 chevy burb. My ac is not blowing very cold and it seems to be a combination of things. First what temp should the ac be blowing out the vent at idle mine is around 58 to 60 degrees. However at idle my alternator only puts out about 8 volts and the fan doesn't put out much air at all until I take off then the volts shoot up to about 14 and the air really blast out still not that cold it blows about 52 to 54 degrees. This brings me to the tranny cooler whoever owned the truck before me put a tranny cooler if front of the condenser(not sue if that is the name for the radiator thingy for the ac). Wouldn't this affect then amount of air the ac gets? and then affect how could my air is? I did convert it to 134a. I have not yet changed the beer can looking thing but will tomorrow I was told this will help.


    so A/C alternator, or tranny cooler or all three? need help
    Gary
     
  2. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    Your troubles are not related. The volt meter reading around 8 volts or so at idle is usually from a bad ground contact somewhere. I am fixing mine tomorrow that does the same thing. I am going to change out both battery cables and of a larger gauge wire while I am at it. Your tranny cooler should not have an affect on your A/C. If not mistaken you can get the A/C to blow about 40 degrees or so at the vents if you replace the dryer and orifice tube and then have it recharged. I hope this helps you.
     
  3. Batchman

    Batchman Registered Member

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    Ok i thing the dryer is the beer can thing what is the tube? Any ideal what ground it could be? I read alot about alternators going bad could that be my problem?
     
  4. dyeager535

    dyeager535 1 ton status Premium Member

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    Just offering my opinion here, but more often than not, the cable *ends* are the problem, and seeing as you can't get good GM battery cables anymore (I didn't last time anyways) I'd suggest cleaning up the terminal ends rather than replacing them, (again, the cables I've seen don't compare to GM quality) unless you are running a substantially higher load. Test voltage (drop) before and after a cable swap at numerous places (fuse panel, battery, alternator) and as long as you already had cleaned the stock terminal ends, I bet you see slight to no change in voltage at any location, unless the cables are visibly damaged already. If you are loosing voltage at connections, the lost voltage has to go somewhere, and it does, as heat, which results in melted wires etc. BTW, one of the 4Wd magazines was having a problem with the cranking power, and their "testing" (voltage readings) showed the same thing...the bigger/newer cables made so little difference, if any, that the problem wasn't resolved. (it was the starter getting cooked by the headers)

    Yes, stock wires are overloaded on starting (whats the starter pull, 400amps? I'm sure that "requires" a lot bigger cables than we can even run, however, this is one reason you don't run the starter for long) but once running, the stock wires should be *more* than able to meet any stock or slightly over, demands made of them.

    Believe me, gone through this on my car, the battery cable size made NO difference whatsoever in cranking power, (403 Olds 9.5:1) it was the starter. (went from .25 to almost .50 outside diameter IIRC) Wires were actually cooking trying to crank it...less than 5 seconds and the wires were hot to the touch. I've spent a lot of time with GM battery cables because of the above : ) Not trying to chastise, just prevent the unnecessary spending of money.

    Wildly fluctuating voltage is typically from a bad voltage regulator, and seeing as a new alternator rebuild kit (yes, they are exceedingly simple to rebuild) is $15, I might try that route also. The voltage WILL fluctuate, but usually 1-1.5v depending on engine RPM. Use the stock gauge as a relative measure, test the alt output with a voltmeter at idle and then with some throttle and see if the stock gauge is correct, and voltage is changing that much. If it is, A) your RPM is too low (bump idle speed up a hair and if voltage surges up then steadies out at like 700RPM, then idle speed is your problem) or B) the voltage regulator is bad, in which case, buy the $15 kit and rebuild it.
     
  5. Batchman

    Batchman Registered Member

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    Did a little test on the way home last night at all the stop signs at idle the voltage only drops if it under load ie the AC is on ect if I turn it off the volts go right back up assuming the gauge is correct I go from about 14 down to 10 I know there is some drop because my lights dim and the fan motor slows way down. I'm going to try the alternator rebuild kit. Do they make one that you jump up the amps on like if mine is stock can i rebuild it to 100 amps? Just curious.

    Thanks for the help
    Gary
     
  6. NITRO

    NITRO 1/2 ton status

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    you can get alternators with 300+ amps, but they do make rebuild kits and u could make it up to 140 with an iceberg rebuild kit.

    NITRO
     
  7. BlazerGuy

    BlazerGuy 3/4 ton status

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    You can take your alternator to AutoZone and they willl test it for free.
     
  8. Batchman

    Batchman Registered Member

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    ok more help is needed I changed the evaporator, orifice tube and refilled with with 4 cans of 134a and it still will only get to blow about 58 degrees. could the compressor be bad or the condensor? I don't know the clutch on the compressor is turning so i assume it is working? I don't know???????????? I need help did i put to much 134 in or not enough? I found a web site that said charge my vehicle with 48oz of 134. So i did 4 cans 12oz each? what gives?
     
  9. 70~K5

    70~K5 1/2 ton status

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    Did you Evac the system? change the dryer? Was it empty or just low?
     
  10. weisel

    weisel 1/2 ton status

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    Replaced the evaporator? Did you mean the dryer (beer can thiny)? Did you pull a vacume on the ac system before putting the 134a in? If not, I think you have normal air in the system where more freon could be.
     
  11. dragricinMT

    dragricinMT 1/2 ton status

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    When you changed your system to R134 you should have replaced the filterdryer, orifice tube,flushed the whole system. R134 I have been told will not blow as cold as R12.
     
  12. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    Thanks for the heads up. But as I am in the automotive field I already knew those things you mentioned. Battery cables do start to deteriorate from the inside out, meaning anywhere along the length of the cable. I also do not want to trust factory cables that are now 14 years old. I also installed a 130 amp alternator along with an auxillary battery and isolator. I have already installed a 4 guage wire from the rear alt. terminal to the battery isolator and now I am going to do the same from the alt. to the main battery. That is the cable I was actually referring to when I said make it a larger gauge cable while at it. When you add extra amperage you must also add larger gauge cable or you stand a chance of an electrical fire from too small a cable. But thanks for the heads up, maybe someone else is reading this post that doesn't know otherwise and will benefit from this info.
     
  13. Batchman

    Batchman Registered Member

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    No i did not have it flushed or vacumed down. I thought it was empty. So I did change the beer can thing and the orifice tube. Should i take it some where and have them vac it down and flush it? Then refill with 134a? Any ideal what the temp should be blowing at I know it is less that 58 degrees Thanks for all the help

    Gary
     
  14. dyeager535

    dyeager535 1 ton status Premium Member

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    It was my understanding that copper won't corrode unless its exposed to the elements? I've cut open 20 year old factory wiring and it looked brand new, isn't the condition of the wire visibly apparent? No Electrician, but I thought I remembered hearing the "skin" of copper wiring was what was important...

    The reason I say don't mess with the factory stuff unless it's visibly toast or you abslutely KNOW its a problem for people is because of the fact that most of the aftermarket cables aren't protected nearly as well as stock GM cables at the terminal ends, allowing the wires to oxidize and get brittle, as well as wreaking havoc at the terminal ends, as they corrode directly under the connector, so thus not visible.
     
  15. dyeager535

    dyeager535 1 ton status Premium Member

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    Volts should never go below 12, and really, no less than about 12.5. Like I said, the gauge is relative. You can be certain your volts *are* dropping that much, so in any case, even if it was on the high side (15, thats not right either) you'd end up with 11v when it dropped back down. As long as engine RPM is correct at idle, even under load it shouldn't drop that much. As bad as these alternators are at idle speeds, the trucks didn't drop that much voltage when new. I have a 78amp alternator on my truck (because I had it lying around) and it is more than plenty. While cruising, I can turn on all accessories on high, and still not see the gauge move. It *will* drop some when I'm at idle, but it's still enough to charge the battery, which is all I want.

    Unless you are running hefty aftermarket stuff that is drawing a lot from the alternator, I'd just stick with the stock unit.
     
  16. dragricinMT

    dragricinMT 1/2 ton status

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    What you need to do is flush the system since it is contaminated. You still had R12 oil plus some R12 in there. Flush the system then put on the filter-drier and orifice tube. The old filter-drier(beer can thing) still had R12 oil in it. Can't completely clean them. Flush first then replace your parts. Talk to a local shop that does A\C work and they should tell you approximate temp for R134. I have been told that R12 oil and the R134 ester and pag oils do not mix, they turn to a gooey mess when mixed.
    Good luck, hope this helps. JR
     

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