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AC BLOWING HOT AIR


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ice
New User

Oct 3, 2017, 9:09 PM

Post #1 of 6 (270 views)
AC BLOWING HOT AIR Sign In

2000
Lexus GS 300
Enging: 3.0
170,000 miles

My AC clutch is engaging, refrigerant is full without a leak. However, it's blowing hot air. The mechanic said that I need a new compressor because the low side psi is normal but the high side is low.


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Oct 3, 2017, 11:32 PM

Post #2 of 6 (261 views)
Re: AC BLOWING HOT AIR Sign In

Need lots more info than that. A/C is it's own trade not for everyone or even every shop. How do you or the shop know it's full? What were the pressures under what conditions?
Know this - you almost can't do just a compressor alone. It's not DIY friendly so suggest finding a shop that really specializes in A/C fully equipped to diagnose and service/repair it and pay the price,


T



ice
New User

Oct 5, 2017, 12:56 PM

Post #3 of 6 (216 views)
Re: AC BLOWING HOT AIR Sign In

Hey Tom thanks for the reply.

If you don't mind, let me give you a the history of the car. I parked the car for 6 months without starting it. I should have known better but the time I started the car the AC was not blowing cold air anymore. So I took my car to an AC shop several months ago and they removed the freon in the system for several hours. When they were ready to check the problem, he said it had a code. Both light sensors on top of my dash board prevented him from making a proper diagnosis. So he suggested to take it to the dealer. I was very busy that day, so I just took the car and left. On my way home, I realized that the car was in the garage facing the wall and the garage was not well lit. So that's the reason why the sensor threw a code. Since the system is already empty, I decided to use AC pro just to check if it will blow cold air. Filled it up as suggested, well, it worked really well for a few months. So I thought it had a slow leak that's why the air started blowing hot air again. Well the system is full. No signs of leak when the guy tested it.

I don't know if this will help. The AC guy used an AC 134a Manifold guage. It was around 90 degrees that day. The clutch was engaging, freon was full, the low reading was 45-46 psi and the high was around 150 psi. He said the high side was to low that's why he suggested to change the compressor.


Sidom
Veteran / Moderator
Sidom profile image

Oct 5, 2017, 1:05 PM

Post #4 of 6 (214 views)
Re: AC BLOWING HOT AIR Sign In


In Reply To
well, it worked really well for a few months.


If he didn't evac the system and recharge it, then you don't know if it's full or not.... When you charged it, hopefully that can didn't have leak sealer in it or that in itself could create some problems....

To diag it correctly "today", the refrigerant need to be removed and the correct weight charged.....

The reading you are getting right now are off.....The high side is low & the low side is high but until you are sure of the correct charge its guessing...






__________________________________________________________________________________________



Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Oct 5, 2017, 4:58 PM

Post #5 of 6 (204 views)
Re: AC BLOWING HOT AIR Sign In

Ice: As Sidom said and I was worried know that you do NOT know a system if "FULL" by pressures which are a diagnostic tool best when known it's properly charged.
That and the "A/C Pro" cans I see in the grocery store about now really don't tell you what's in it and gauges on those also called "Death Kits" by the trade are almost never close to accurate nor explain you must know at what temp air is coming thru grille and the engine's RPM or you are asking for what might have been an easy fix to be a total disaster. A/C is one if not the worst where doing something wrong can and will ruin up to thousands of bucks worth of other stuff to really get it right.


The guess of the day since you didn't say if at any temp and raised idle (we'll never know what) it's low from a leak as about 65% of all poorly performing A/C is caused by.


Now if you didn't purge the hose on the death kit you added air. NONE - like really NONE is allowed nor the shop that put real gauges on it did they purge lines or allow air in from those fooling around.


Problem is air is full of moisture and also doesn't condense at all from a vapor to a liquid and will throw off all readings so must be totally evacuated and charged to exact spec to know if system is on a leak to fix but worse the air already added some moisture to now PAG oils which turn acidic in some time and destroy everything refrigerant touches! Interesting there are no warning about that and half the shops that even touch A/C wouldn't know - you need real help if you want this to work and last which is why I said it's not DIY friendly nor for even every shop that you should best seek out before you destroy it any more.


If no air somehow and above 80F you are still too low and can't say by how much. It's not something that gets stolen or consumed it leaks and takes time for some to find out where if slow or intermittent,


T



ice
New User

Oct 10, 2017, 7:09 AM

Post #6 of 6 (167 views)
Re: AC BLOWING HOT AIR Sign In

Thank you!






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