AC Hi & Low side same

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  #1  
Old 09-14-07, 01:15 PM
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AC Hi & Low side same

87 4Runner SR5 4WD 22 RE engine
Was converted from R12 to 134a number of years ago.

Hi & low side both measure the same. The other day when engine was opertating temp and outside temp was close to 100degrees Hi & Low measured around 125 each. Today outside temp in mid 70's and engine not warmed up and both sides measure 95lbs.

Am I looking at expansion valve? compressor?. What's my best way to test this problem?
 
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  #2  
Old 09-14-07, 02:21 PM
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What was replaced with the swap over to 134a? Converting requires the replacement of almost every component in the system. Since 134a has a much higher operating pressure and the molecules of the gas are smaller, seals will leak alot easier.
 
  #3  
Old 09-14-07, 03:35 PM
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Hey Mark. I purchased the vehicle around 94 or 95 and the coversion had already been done so I'm just not sure what to tell you about what was replaced. I'm not even sure if the orings were changed. but everything has worked okay, not great mind you but okay until the other day. What I picked up today was expansion valve, o-ring kit and adapter fittings for R12 to 134a (the old ones look kinda buggered).

If hi and low side read the same am I on the right track thinking maybe the expansion valve may be bad because like an orifice tube doesn't that seperated the hi & low sides?

This is the old vehicle my sons and I used to get to fishing hole, hunting camp etc but nice to have ac on the way.
 
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Old 09-14-07, 03:46 PM
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Pressures should be the same on high and low with vehicle off, if they are the same with it on, it could be the compressor itself.

Do you hear and/or see the AC compressor clutch engaging when you turn it on?

There is a dye kit you can introduce into the system, and with a UV light, you can find leaks if you have any, or else have a shop check that portion.
 

Last edited by HotxxxxxxxOKC; 09-14-07 at 03:48 PM. Reason: added dye
  #5  
Old 09-15-07, 08:36 AM
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Hey Mark, I checked the compressor and it is not kicking in at all. If it matters the clutch turns freely by hand. Borrowed a UV light and glasses from a bud of mine and injected some dye but cannot find any leaks but not sure how much dye actually went into the system. I tried to check everything with the light. I followed the lines from the firewall, compressor and dryer. I tried to look at the cooling unit under the dash where my expansion valve is but everything in the way so may not be able to see that anyway.

Sorry it took so long but we came back from the ball game last night my son had taken the 4Runner to the camp so had to wait till he got back today.

Any ideas???
Dennis
 
  #6  
Old 09-15-07, 10:55 AM
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there is enough pressure in the system that it should atleast engage the compressor, so I would start looking at electrical things like fuses, switch, relay, you might check for power to the compressor or even jumper power just to make sure the compressor does engage but it sounds like an electrical problem.
 
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Old 09-16-07, 09:31 AM
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It was an electrical problem. The power wire on the clutch had somehow broken way up by the wheel well where it come out of the harness. Then broken end at the harness stayed up top but the other side of the brake fell down the block by the oil sensor so I spent bunch of time down there trying to find where it went first. Finally started looking up top and saw the broken wire at harness. It tested 12v/0v as I turned the a/c switch on/off so I hooked it up and back going now.
Thanks everyone
 
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