Vehicles that have dual Evaporators and dual TXV
Posted: Thu Sep 17, 2026 4:03 pm
Hello!
Anyone ever had a failure of a rear TXV on a vehicle that had front and rear evap cores and expansion valves while the compressor, front TXV, drier and pressure switch were known to be working properly?
I'm azzuming that it's likely a closed single loop system whereby a clogged / blocked rear TXV would cause total system failure and potentially the following symptoms even if the FRONT TXV and everything else is working fine.....
1). No cold air from the front (or rear) AC vents (because refrigerant cant move around the system)
2). High Low Side pressure and Low High Side Pressure?
On this vehicle (2001 Dodge Grand Caravan), the one compressor and one drier facilitate both the front TXV and front evap core as well as the rear TXV and rear evap core. Therefore, if at any point in the extension lines leading to the rear AC components there is a leak or obstruction, or if the TXV is plugged or stuck closed, it will directly affect the entire AC system. In the Factory Service Manual I cannot find any reference to any way the rear refrigerant lines can be redirected or seperated from the front AC refrigerant lines.
My conclusion is that I likely have a failed rear TXV since the vehicle has a new compressor, new front TXV, new receiver drier, new high pressure switch, the system was thoroughly flushed, vacuumed at -50 millimeters of Hg for nearly 2 hours and the system still does not work.
Unless.......the condenser is blocked up really good.
Can someone confirm or debunk this please
Thank you in advance.
Anyone ever had a failure of a rear TXV on a vehicle that had front and rear evap cores and expansion valves while the compressor, front TXV, drier and pressure switch were known to be working properly?
I'm azzuming that it's likely a closed single loop system whereby a clogged / blocked rear TXV would cause total system failure and potentially the following symptoms even if the FRONT TXV and everything else is working fine.....
1). No cold air from the front (or rear) AC vents (because refrigerant cant move around the system)
2). High Low Side pressure and Low High Side Pressure?
On this vehicle (2001 Dodge Grand Caravan), the one compressor and one drier facilitate both the front TXV and front evap core as well as the rear TXV and rear evap core. Therefore, if at any point in the extension lines leading to the rear AC components there is a leak or obstruction, or if the TXV is plugged or stuck closed, it will directly affect the entire AC system. In the Factory Service Manual I cannot find any reference to any way the rear refrigerant lines can be redirected or seperated from the front AC refrigerant lines.
My conclusion is that I likely have a failed rear TXV since the vehicle has a new compressor, new front TXV, new receiver drier, new high pressure switch, the system was thoroughly flushed, vacuumed at -50 millimeters of Hg for nearly 2 hours and the system still does not work.
Unless.......the condenser is blocked up really good.
Can someone confirm or debunk this please
Thank you in advance.