Parts for your 1999 Ford Mondeo-Tx valve

1999 Ford Mondeo TX Valve: What it does and when to replace it

Based on technical references including the Ford TIS/Workshop Manual for Mondeo (Mk2, 1996–2000, Section 412-00 Air Conditioning) and mainstream component catalogues from OE suppliers such as Denso, Hella/Behr and Nissens for the same model years, the 1999 Ford Mondeo is fitted with a thermostatic expansion valve (TX valve) at the evaporator inlet, not an orifice-tube/accumulator system. These sources identify the valve’s location at the bulkhead/evaporator connection and outline remove/install procedures for the expansion valve on this platform.

The TX valve meters liquid R134a into the evaporator, maintaining the right superheat so the evaporator stays cold without letting liquid refrigerant return to the compressor. It adapts flow to cabin load (hot day, high fan speed, recirc vs fresh air), helping the Mondeo cool quickly at the lights and stay efficient on the motorway. By keeping the evaporator from icing and the compressor from slugging, it protects hardware and keeps fuel use sensible.

When a Mondeo’s TX valve starts to stick or clog, owners often notice weak or intermittent cooling, vent temperature swings, a frosty valve or outlet pipe at the firewall, or odd hissing. A gauge set will typically show low evaporator pressure with poor cooling (starved) or high low-side and poor cooling (flooding), but diagnosis should be done by an A/C tech.

• Common causes of TX valve trouble: moisture in the system, desiccant breakdown in the receiver-drier, debris from a failing compressor, or long intervals between A/C servicing.
• Best-practice replacement: recover refrigerant, remove the valve at the evaporator inlet, renew all O-rings, and replace the receiver-drier. Flush lines (except the compressor and TX valve), evacuate with a vacuum pump, leak-test, then recharge to the under‑bonnet spec with the correct PAG oil.

On the 1999 Mondeo the valve is typically accessible where the A/C pipes enter the cabin at the bulkhead. Given Australia and New Zealand regulations, refrigerant work must be carried out by a licensed technician (ARCtick in Australia). Keeping the cabin filter clean and using the A/C regularly helps the valve and evaporator run at stable temperatures, which can extend component life.

Popular questions

Where is the TX valve on a 1999 Ford Mondeo?
It’s mounted at the evaporator inlet where the A/C pipes pass through the bulkhead. On most cars it can be accessed from the engine bay at that firewall connection, with the sensing bulb fixed to the evaporator outlet.

Does this Mondeo use an orifice tube instead of a TX valve?
No. Technical documentation and parts catalogues for the 1996–2000 Mondeo specify a thermostatic expansion valve with a receiver-drier. Mixing in an orifice-tube/accumulator setup isn’t compatible with the system design.

Should the receiver-drier be replaced when changing the TX valve?
Yes. Any time the circuit is opened—especially when addressing metering or contamination issues—the receiver-drier should be renewed to control moisture and protect the new valve and compressor.