1998 Mustang AC pressure fluctuates on gauge with bad idle
04-21-2019, 10:35 AM
#1
Thread Starter
Join Date: Mar 2018
Location: Florida
Posts: 38
1998 Mustang AC pressure fluctuates on gauge with bad idle
So my car stopped putting out cold are about a month ago. I realized something was wrong and not wanting to burn out my A/C clutch or just break the compressor in general, I've tried to keep the A/C off.
I went to get a refrigerant refill kit and when I read the pressure, it fluctuated up and down. Did some research and found that if it's fluctuating, it's low. However, when I actually started refilling it immediately hit red on the gauge, whether compressor was engaged or not. The pressure fluctuates as the compressor engages and disengage. Here is a video: https://drive.google.com/file/d/16Ln...ew?usp=sharing
I say when the compressor is and isn't engaged for reference. I should note that RPM drops and power loss happens exactly when the pressure drops and the compressor is engaged. Engine visibly shakes and compressor sounds like it's struggling when on.
Any help is appreciated, thanks!
I went to get a refrigerant refill kit and when I read the pressure, it fluctuated up and down. Did some research and found that if it's fluctuating, it's low. However, when I actually started refilling it immediately hit red on the gauge, whether compressor was engaged or not. The pressure fluctuates as the compressor engages and disengage. Here is a video: https://drive.google.com/file/d/16Ln...ew?usp=sharing
I say when the compressor is and isn't engaged for reference. I should note that RPM drops and power loss happens exactly when the pressure drops and the compressor is engaged. Engine visibly shakes and compressor sounds like it's struggling when on.
Any help is appreciated, thanks!
04-22-2019, 01:24 PM
#2
Gentleman's Relish
Join Date: Feb 2005
Location: AZ
Posts: 13,090
When you refilled it, was the engine running? Engine should be running anytime you add refrigerant.
That low side guage is only giving you half the picture. You need a manifold gauge set to see what's going on, on the high side. If the high side is also fluctuating then your orifice valve is probably clogged. The orifice valve is what separates the high/low side of your system. It's basically a very thin mesh/screen that sets a certain amount of restriction in the liquid flow of your refrigerant. When it clogs, it can create a fluctuation like that.
That low side guage is only giving you half the picture. You need a manifold gauge set to see what's going on, on the high side. If the high side is also fluctuating then your orifice valve is probably clogged. The orifice valve is what separates the high/low side of your system. It's basically a very thin mesh/screen that sets a certain amount of restriction in the liquid flow of your refrigerant. When it clogs, it can create a fluctuation like that.
10-02-2019, 05:13 PM
#3
Thread Starter
Join Date: Mar 2018
Location: Florida
Posts: 38
When you refilled it, was the engine running? Engine should be running anytime you add refrigerant.
That low side guage is only giving you half the picture. You need a manifold gauge set to see what's going on, on the high side. If the high side is also fluctuating then your orifice valve is probably clogged. The orifice valve is what separates the high/low side of your system. It's basically a very thin mesh/screen that sets a certain amount of restriction in the liquid flow of your refrigerant. When it clogs, it can create a fluctuation like that.
That low side guage is only giving you half the picture. You need a manifold gauge set to see what's going on, on the high side. If the high side is also fluctuating then your orifice valve is probably clogged. The orifice valve is what separates the high/low side of your system. It's basically a very thin mesh/screen that sets a certain amount of restriction in the liquid flow of your refrigerant. When it clogs, it can create a fluctuation like that.
Any idea if it's okay to run the hot air if this is the problem?
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