98 tahoe needs a/c help
May 24th, 2010, 1:07 PM
#1
CF Veteran
Thread Starter
98 tahoe needs a/c help
compressor seems to be working, the clutch kicks on for couple seconds, off bout 5-8 sec, repeating this steadily. i used a can of 134a, charged system as directed, doesn't seem to be helping. inside the rig is way hotter than outside, no cold air. checked the pressure on low side a dozen times, has remained steady at 45psi, per 85 degree ambient temp, as directed on can. someone mentioned expansion valve, or maybe the compressor. any one help me out?
Last edited by maxxman04; May 24th, 2010 at 1:50 PM.
May 24th, 2010, 4:24 PM
#2
Administrator
Lo pressure of 45 psi is too high. Not sure how it remains steady if the compressor is cycling.
What are the lo and hi pressures when the compressor is running and when it shuts off?
What are the lo and hi pressures when the compressor is running and when it shuts off?
May 24th, 2010, 4:41 PM
#3
CF Veteran
Thread Starter
low pressure of around 25 psi when it starts to cycle then up to 45 when cycle stops. according to the directions, chart, 45 psi in low side is correct for 85 degree ambient temp. this is also the psi that a/c clutch started cycling when i first put the 134a into system. compressor won't cycle under 40 psi.
May 24th, 2010, 5:25 PM
#4
Administrator
Without knowing the hi pressure, I'm guessing that either the system is undercharged or clogged.
If undercharged then you need to find the leak or you're just flushing money down the toilet.
If undercharged then you need to find the leak or you're just flushing money down the toilet.
May 24th, 2010, 9:10 PM
#5
Super Moderator
Professional Mechanic
Professional Mechanic
Low side seems kind of high to me also. If that # with the clutch engaged? Really would need to know high side. Generally short cycling is a low charge.
May 26th, 2010, 7:02 AM
#6
CF Veteran
Thread Starter
UPDATE. is did turn out to be low charge. the 45 was not with clutch cycling. online research got me the right info on how to charge. got system to about 28psi on low side with clutch cycling, ran out of 134a. ac still not ice cold, but way better than it was. ac cycles alot better too. gonna get another can, try to get 30-35 psi in it, get it a little cooler yet. but it's alot better now. thanks for all the input.
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May 26th, 2010, 4:01 PM
#8
CF Veteran
Thread Starter
haven't found any leaks, but don't have a sniffer to find it. lost 2 psi in three days with ac running quite a bit, so can't be to big of leak. will have to figure it out tho cause yeah, could get spendy
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