Parts for your 2007 Nissan Maxima-Tx valve

2007 Nissan Maxima TX valve — what it does and how to look after it

Technical sources confirm the 2007 Nissan Maxima is built with a thermal expansion valve (TXV), not an orifice tube. The Nissan Factory Service Manual (2007 Maxima, HA – Heater & Air Conditioning) depicts an expansion valve mounted at the evaporator, and the OEM parts catalogue lists an A/C “expansion valve” for this model. Major aftermarket catalogues (Denso, Four Seasons) also supply direct-fit TXV units for 2004–2008 Maxima, reinforcing that a TXV is the correct metering device for this car.

On this Maxima, the TX valve meters refrigerant into the evaporator based on temperature and pressure, keeping superheat in check so the evaporator doesn’t ice up and cabin temps stay steady. That precise control helps the compressor live a longer, happier life and gives more consistent cooling in Aussie and Kiwi summers.

The TXV itself isn’t a periodic “service” item, but the system around it is. If the air-con’s struggling at idle, the vent temps hunt hot–cold, or there’s frost on the evaporator lines, a sticking or contaminated TXV could be on the cards. After a compressor failure, metal debris can clog the valve, so smart workshops replace the TXV and drier/desiccant and flush what’s serviceable to protect the new hardware.

Replacement on a 2007 Maxima is a technician’s job because the system must be recovered, evacuated and re-gassed by an ARCtick-licensed pro. The valve is fitted at the evaporator on the heater/cooling unit, access typically involves work at the dash side and the firewall line connections. Correct O-rings, light PAG oil on seals, and factory torque on the TXV screws are all must-dos. Charge by weight to the placard spec and verify performance with manifold gauges and a thermometer to confirm stable superheat and outlet temps.

Good practice when the TXV is touched or the system’s been open:

• Replace the receiver/drier or desiccant bag and any disturbed O-rings.
• Flush lines and condenser if contamination is suspected, never flush the TXV or compressor.
• Vacuum for the full time recommended in the FSM, then leak-test before charging with R-134a.
• Check condenser air flow, cabin filter condition, and blower performance to rule out airflow issues that mimic TXV faults.

Looked after this way, the Maxima’s TX valve quietly does its job for years, keeping the cabin chill and the compressor comfortable.

Popular questions

Where is the TX valve on a 2007 Nissan Maxima?
The TXV is mounted at the evaporator on the heater and cooling unit. The refrigerant pipes pass through the firewall to this valve. Access usually involves trim and glovebox-area work inside, plus disconnecting the lines at the firewall in the engine bay.

What are common signs the TX valve is failing?
Tell-tales include weak cooling at idle, temperature swings from the vents, hissing and frosting near the evaporator lines, and abnormal gauge readings. These symptoms can overlap with low refrigerant or a blocked condenser, so proper diagnosis with gauges and temperature checks is essential.

Does the TX valve need routine replacement?
No routine interval is specified. It’s typically replaced if sticking, leaking, contaminated, or whenever the system has suffered a compressor failure. Whenever the TXV is changed, best practice is to renew O-rings, replace the drier/desiccant, evacuate thoroughly and re-gas to spec.