Parts for your 1997 Daihatsu Gran move-Tx valve

1997 Daihatsu Gran Move TX Valve – What It Does and When to Replace It

Based on technical sources, the 1997 Daihatsu Gran Move (also known as the Pyzar, chassis family G3/G300) does use a thermostatic expansion valve (TX valve) in its air-conditioning system. The Daihatsu Gran Move/Pyzar workshop manual HVAC section specifies a block-type expansion valve at the evaporator inlet behind the dash. This layout is consistent with Denso-supplied A/C hardware of the era, and is corroborated by Denso component catalogues and aftermarket parts listings from major suppliers that list a dedicated expansion valve for the 1996–2002 Pyzar/Gran Move range.

On this model, the TX valve’s whole job is to meter the flow of R134a into the evaporator, reacting to evaporator outlet temperature and pressure so the core stays cold without freezing. That keeps vent temps low, cabin comfort up, and compressor load in check. When the valve sticks or mis-meters, drivers typically see weak cooling at idle, frosting on the evaporator line, hunting vent temperatures, or odd gauge readings (starved low side, or low superheat) during diagnosis.

Servicing-wise, the TX valve isn’t a “maintenance” item, it’s replaced if faulty or whenever the system has suffered contamination or a major component failure. On the Gran Move it’s a block-type unit mounted at the evaporator inlet, accessed by removing the glovebox/evaporator cover and disconnecting the two A/C pipes at the firewall. Always recover the refrigerant properly, cap open lines, and replace the green HNBR O-rings. It’s smart practice to fit a new receiver–drier any time the system’s opened, and to flush lines if there’s evidence of debris or a burnt-out compressor. Use the correct PAG oil type/quantity for replaced parts and recharge R134a by weight to the under‑bonnet spec label.

A few friendly tips for DIYers and workshops in Aus/NZ:

• Confirm TX valve fault first: compare vent temps, line temps, and high/low pressures, rule out low charge, a dying condenser fan, or a restricted drier.
• Handle the sensing components carefully, don’t bend or crush capillary elements if present, and avoid over‑torquing the block bolts—follow the workshop manual specs.
• After reassembly, pull a deep vacuum (at least 30 minutes on a warm day), perform a static leak test, then charge by weight. Check superheat and vent temps on road test.

Done right, a fresh TX valve restores crisp, consistent cooling and takes the hard yakka off the compressor during hot Aussie and Kiwi summers.

Popular questions about the 1997 Daihatsu Gran Move TX valve

Where is the TX valve located on a 1997 Gran Move?
It’s a block-style valve mounted at the evaporator inlet, behind the dash on the passenger side. Access is typically via the glovebox area and the evaporator case. The refrigerant pipes pass through the firewall right there, so you’ll disconnect them in the engine bay and unbolt the valve inside.

What are common symptoms of a failing TX valve on this model?
Weak cooling at idle but better on the highway, evaporator line frosting, vent temperatures that surge hot–cold, and pressure readings showing a starved low side are classic. Of course, similar symptoms can come from low refrigerant, a slow condenser fan, or a restricted drier, so confirm with proper A/C diagnostics.

Can a TX valve be cleaned or adjusted, or should it be replaced?
There’s no practical adjustment. If it’s sticking or contaminated, replacement is the reliable fix. Whenever you replace the TX valve, fit new O-rings, consider a new receiver–drier, evacuate thoroughly, and recharge to the factory weight. That prevents repeat issues and keeps the air‑con humming.