Quinton Hazell Thermostat & Short Housing • QTH794K

Quinton Hazell QTH794K Thermostat & Short Housing

Replacement Quinton Hazell coolant thermostat and short housing assembly for Mazda MX-5 MK3/NC 1.8 and 2.0 petrol models within the applicable early chassis-number range.

The thermostat regulates coolant flow between the engine and radiator, helping the engine reach and maintain its correct operating temperature. QTH794K is designed as an aftermarket replacement for the original component on the applications listed.

A common thermostat failure is sticking open, which can cause slow engine warm-up, unusually low coolant temperature and reduced heater performance. A thermostat that sticks closed can instead cause rapid overheating and requires immediate attention.

• Part type: Engine coolant thermostat and short housing
• Thermostat opening temperature: 82°C
• Housing type: Short version
• Supplied with gasket / seal
• Application: Early Mazda MX-5 MK3 / NC
• Engine compatibility: 1.8 and 2.0 petrol
• Applicable chassis range: 115785 to 124657 inclusive
• Quantity per vehicle: 1
• Quantity supplied: 1 thermostat assembly
• Brand: Quinton Hazell
• Part No.: QTH794K
• EAN: 5050438421989
• Designed as an aftermarket replacement for the original component on the applications listed

Fitment advice: This is the short-version thermostat assembly and does not fit every NC despite the engines being otherwise similar. MazSpec specifies QTH794K for early vehicles with chassis numbers 115785 to 124657 inclusive. Some other early MK3/NC vehicles require a different-length thermostat assembly, so the chassis number and existing housing style should be checked before ordering.

Other items to consider: Engine coolant, radiator hoses, expansion-tank cap, water pump and auxiliary drive belt.

Useful tools / consumables: Correct-specification coolant, drain pan, hose-clip pliers, socket set, torque wrench and cleaning materials.

Difficulty guide: DIY Difficulty: Moderate. The cooling system must be partially drained, the sealing surfaces cleaned correctly and the system refilled and bled after installation.

Why Quinton Hazell? Quinton Hazell is a long-established automotive aftermarket brand, offering dependable replacement parts for servicing and repair. Its components are designed as practical aftermarket replacements for the original parts on the applications listed.

What’s in the box: 1 × Quinton Hazell QTH794K thermostat / short housing assembly with gasket or seal.

Installation notes: Allow the engine to cool completely before opening the cooling system. Drain sufficient coolant, remove the existing thermostat assembly and clean the mating surfaces. Install the replacement with its seal correctly positioned, refill with the appropriate coolant mixture and bleed the cooling system thoroughly. Check for leaks and confirm normal operating temperature after installation.