Chasing an HVAC issue and I need some help here...

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Jimmy Brooks

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It could just be a blend door issue. From limited experience with replacing blend door motors, I believe if the blend door that closes the heater core off when the ac is on, doesn't close all the way, then you will get heat mixed with the cold air. I had this issue on an F150 and a Suburban.

I remember getting a drivers side blend door issue on my LR4 when I let the battery get too low. You can check some of the blend door positions with the GAP tool. If they are malfunctioning, then it should show a fault.

You will need to check the high side and low side pressure with a gauge set to ultimately see if the expansion valve is working. If you want to do it yourself, you can buy a gauge set from harbor freight for $65, and google what the pressure readings mean. Thats what I ended up doing.

I also found out the hard way, that if you are leaking refrigerant, a service center is not allowed to refill it unless its fixed. So, I went from a weak a/c system to no a/c at all after I had them evac the system and pull a vacuum on it to test for leaks. However, when I pulled a vacuum on it myself, it held steady for 45 min and I just refilled it. So I am guessing they were trying to get me to spend some money.

I never got faults for blender doors, plus the fact that all vents would blow cold ac when it was less hot out and when the blower motor was turned down makes me think it is something with the actual system.

My thought is that I could’ve had a possible faulty expansion valve (at least for the rear climate) because in theory a bad valve can cause a compressor to be less effective and even lock up as mine did due to the fact that the Freon liquid can’t be compressed. It can also cause leaks as my system now has one.

One thing I can’t wrap my head around is the smell of Freon in the cabin… could an expansion valve cause the system to obtain a leak in the evaporator?

At the end of the day it seems like I’m tearing the whole dash apart and the whole rear system apart regardless so I might aswell do both of the expansion valves at the same time as both evaporators. But I’m also fairly new to the whole understanding of ac systems so I want to make sure what I’m thinking actually makes sense.

What I do know as of now is that there is a leak because I have a code for low Freon and my ac doesn’t work. My issue is that I’m currently not with the car so I can’t test the high and low side of the system. Just trying ti make sense of the issue based on everything I know.
 
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RoverTide

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Not sure if a bad expansion valve would cause a leak in the evap. But before I took the dash apart, I would make damn sure the issue was one of those two parts. I think I would at a minimum, confirm there are no leaks in any of the accessible plumbing (spraying soapy water?), and have someone run a refrigerant sniffer to see if that can pinpoint where the leak is.
 

Jimmy Brooks

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Not sure if a bad expansion valve would cause a leak in the evap. But before I took the dash apart, I would make damn sure the issue was one of those two parts. I think I would at a minimum, confirm there are no leaks in any of the accessible plumbing (spraying soapy water?), and have someone run a refrigerant sniffer to see if that can pinpoint where the leak is.

Definitely agree, I’ll pinpoint the leak before replacing anything.

Would anything else cause the Freon smell to come inside the cabin?
 

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