RIDEX Coolant Temperature Gauge Sender – MX-5 NA/NB • 830C0065

RIDEX 830C0065 Coolant Temperature Gauge Sender – MX-5 NA/NB

Replacement single-pin engine coolant-temperature sender for Mazda MX-5 Mk1/NA, Mk2/NB and Mk2.5/NB-FL models from 1990–2005.

This sender is installed in the engine cooling system and supplies the temperature signal used by the dashboard coolant-temperature gauge. Its electrical resistance changes as coolant temperature rises, allowing the instrument cluster to display the approximate engine temperature.

Important: This is the single-terminal sender for the dashboard temperature gauge. It should not be confused with a separate two-pin or multi-pin engine coolant-temperature sensor used by the engine-management system.

Common symptoms of a failing sender include a temperature gauge that remains cold, reads incorrectly, moves intermittently, displays an implausibly high temperature or responds when the connector or wiring is disturbed. Similar symptoms can also be caused by damaged wiring, poor grounding, instrument-cluster faults, low coolant level or an actual cooling-system problem.

• Part type: Engine coolant-temperature gauge sender
• Function: Supplies coolant-temperature information to the dashboard gauge
• Electrical connection: Single pin / terminal
• Thread size: M16 × 1.5
• Housing colour: Green
• Approximate weight: 0.03 kg
• EAN: 4059191351879
• Quantity required: 1
• Quantity supplied: 1 sensor
• Brand: RIDEX
• Part No.: 830C0065

Fitment advice: MazSpec confirms compatibility with all standard Mazda MX-5 Mk1/NA and Mk2/NB variants from 1990–2005. Before ordering, confirm that the original component is the single-terminal gauge sender with an M16 × 1.5 thread. Vehicles with modified engines, cylinder heads, wiring looms or aftermarket instruments should be checked individually.

Other items to consider: Inspect the electrical connector, terminal, wiring and engine grounds before replacing the sender. Also check the coolant level, thermostat operation, radiator fan operation and cooling system for leaks if the gauge is indicating an abnormal engine temperature.

Useful tools / consumables: Correct deep socket or spanner, ratchet, drain tray, suitable coolant, electrical contact cleaner and an appropriate thread seal or sealing washer only where specified by the vehicle or sensor manufacturer.

Difficulty guide: DIY Difficulty: Easy to Moderate. Access is generally straightforward, but coolant may escape when the sender is removed and the threaded installation point must not be overtightened.

Why RIDEX? RIDEX sensors provide a cost-effective aftermarket replacement manufactured to defined thread and electrical-connection specifications. This sender is designed to restore a reliable dashboard coolant-temperature signal when the original unit has failed.

What’s in the box: One RIDEX coolant-temperature gauge sender. Electrical connector, wiring, coolant and installation tools are not included.

Installation notes: Allow the engine to cool completely before opening or working on the cooling system. Disconnect the electrical terminal and position a drain tray beneath the sender. Remove the original sender using the correct tool and compare its thread and terminal arrangement with the replacement. Install the new sender carefully by hand before tightening to the applicable specification. Do not overtighten it into an aluminium housing or cylinder head. Reconnect the electrical terminal, restore any lost coolant, bleed the cooling system correctly and inspect for leaks. Run the engine while monitoring the gauge and verify that the reading rises normally as the engine warms.