A/C Manifold Gauge Pressures

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Clovis, CA
2000 Buick LeSabre

At Time of Gauge Reading:
Ambient Temperature 72 F - 51% Humidity

Factory Service Manual Specifications:
Ambient Temperature 70 F Below 40% Humidity
Low Side (32-38 psi) High Side (160-190 psi)

Ambient Temperature 70 F Above 40% Humidity
Low Side (34-40 psi) High Side (175-205 psi)

Measured Gauge Readings:
Low Side (36 psi) High Side (160 psi)

Am I still low on charge ?
confused2.gif
 
Looks a little low, With your temp & humidity, I would like to see 185-210 on the high side.

I'm sure the A/C Nazi's will be by shortly to tell me I'm wrong & you need to vacuum it down & weigh the proper amount of freon back in the system.....Technically they're correct, If I had a leaky POS Harrison HT6 compressor......I would just keep it charged with a little oil.
 
Did you have a big fan blowing over the condenser?

Id say a little bit low, but at this point vent temperatures tell the story. You could add an incremental amount to the system, very small amounts at a time, and watch if the vent temperatures keep dropping. If they don't, or worse, if they start to go up, you've gone too far.
 
JHZR2

Both cooling fans turn at high speed whenever the A/C is on, so I think maybe the answer is yes.

Vent temperatures at the time of pressure reading were (41.2 F - 42.0 F)

Actual ambient temperature at the time of pressure reading was (72.2 F)
 
Originally Posted By: Merkava_4
Vent temperatures at the time of pressure reading was (41.2 F - 42.0 F)


Those are very good vent temps and should go even lower when the vehicle is at speed. Pressures look okay as well, a tad low on the high side but they are many variables that can affect that.

I wouldn't add more refrigerant unless the A/C feels like its not cooling well on the next hot day.
 
Originally Posted By: Rock_Hudstone
Originally Posted By: Merkava_4
Vent temperatures at the time of pressure reading was (41.2 F - 42.0 F)


Those are very good vent temps and should go even lower when the vehicle is at speed. Pressures look okay as well, a tad low on the high side but they are many variables that can affect that.

I wouldn't add more refrigerant unless the A/C feels like its not cooling well on the next hot day.

+1

41-42 is good at idle. What's the temp while driving down the road for a few minutes?

Did you fix the left side vents being warmer than the right side vents?
 
Originally Posted By: Nick1994
Did you fix the left side vents being warmer than the right side vents?


Yes! What led me to the refrigerant direction was that I tested all the mode door operations and the left side vents shut completely off when switching from front vents to front defrost to blow air up onto the front windshield. And then all the temperature changes worked good too. I was all prepared to change a blend door actuator if need be.

Hey Nick, what kind of vent temperatures do you get when it's over a 100 F outside ?
 
When I did AC I always tried for around 1500-2000 RPM, AC set to "recirculate", as well as a large fan blowing at the front of the car over the condenser.

In a perfect world, at 70F ambient, I would expect vent temps around 35F. Generally OEMs spec somewhere around 40F under ambient as allowable. Honestly on any full size American vehicle, at least 50F below ambient is expected (down to about 35F outlet temp).
 
Originally Posted By: punisher
In a perfect world, at 70F ambient, I would expect vent temps around 35F. Generally OEMs spec somewhere around 40F under ambient as allowable. Honestly on any full size American vehicle, at least 50F below ambient is expected (down to about 35F outlet temp).

This a 17 year old vehicle.

I'm jumping in late here but assuming most, if not all of the cooling system is OE vent temps around 40F at idle is not bad in my humble opinion.
 
Originally Posted By: Merkava_4
Originally Posted By: Nick1994
Did you fix the left side vents being warmer than the right side vents?


Yes! What led me to the refrigerant direction was that I tested all the mode door operations and the left side vents shut completely off when switching from front vents to front defrost to blow air up onto the front windshield. And then all the temperature changes worked good too. I was all prepared to change a blend door actuator if need be.

Hey Nick, what kind of vent temperatures do you get when it's over a 100 F outside ?
I'll have to put my thermometer back in the car. Usually 38-40, I drive a lot of highway so it gets lots of flow over the condenser. Electric fans don't pull enough air over it.
 
Originally Posted By: Nick1994
I'll have to put my thermometer back in the car. Usually 38-40, I drive a lot of highway so it gets lots of flow over the condenser. Electric fans don't pull enough air over it.


38-40 is quite excellent for 100 F at idle.

It was 107 F in the garage today and the lowest vent temp I could get is 58 F.
 
I have a Harbor Freight AC manifold gauge and used it for my 2008 Hyundai Accent. Today I tried to hook it up to my 2010 Hyundai Genesis Coupe. I could get the high side to snap on but not he low side. Are there two different sized low side nipples?
 
All 134a car couplers are the same two sizes, 13mm low side and 16mm high. Many people have had trouble with the Harbor Freight set not coupling properly.
 
Originally Posted By: SHOZ
I have a Harbor Freight AC manifold gauge and used it for my 2008 Hyundai Accent. Today I tried to hook it up to my 2010 Hyundai Genesis Coupe. I could get the high side to snap on but not he low side. Are there two different sized low side nipples?


When you look under the hood for the Genesis, does it say r134a? Or does it maybe have r1234YF?
 
It's r134a and I literally just had it on the Accent and it popped right on. Maybe it's due to the strut bar being in the way.
 
I apologize if my questions seem dumb, I'm still new to using AC manifold gauges.

Did you unscrew the knob on the coupler before taking it off the other car, or before trying to put it on the Genesis? If it's tightened down it might be fighting the Schrader valve pressure.
 
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