Customizable Overheat Warning

Unlike gauges with a fixed warning point, this model allows the driver to select a temperature threshold appropriate for the application.

To configure the alarm:

1. Press and hold the WARN button.
2. Use WARN (+) to raise the threshold.
3. Use PEAK (-) to lower the threshold.
4. Stop pressing the buttons and wait approximately three seconds.
5. The selected warning temperature saves automatically.

When the measured temperature reaches the selected threshold, the display flashes to alert the driver.

The warning feature cannot prevent engine damage by itself, but it can provide time to reduce load or safely shut the engine down. Sadly, it cannot make someone stop driving while steam pours from the hood. Technology has limits.

Peak-Temperature Recall

Press the PEAK button to display the highest temperature recorded during operation.

Peak recall is especially helpful when diagnosing intermittent temperature increases that occur during:

• Towing
• Steep climbs
• Hard acceleration
• Extended idling
• Off-road driving
• Track sessions
• High ambient temperatures

Instead of staring at the gauge throughout the drive—which is generally frowned upon by other motorists—you can review the highest recorded reading afterward.

High-Contrast LED Display

The digital LED screen is designed for quick reading in different lighting conditions. Its numerical format eliminates the guesswork associated with estimating the position of an analog needle.

Mount the gauge within the driver’s normal field of view without obstructing the windshield, factory instruments or other controls.

Compact 2-Inch 52mm Housing

The 2-inch, or 52mm, gauge housing fits many universal dashboard openings, mounting panels and gauge pods.

The included bracket and adhesive backing provide multiple mounting options for compatible:

• Passenger cars
• Pickup trucks
• SUVs
• RVs
• Tow vehicles
• Off-road vehicles
• Performance cars
• Boats and marine vehicles
• Custom builds

Measure the mounting location before drilling or cutting. “Universal” fitment has caused more unnecessary dashboard surgery than anyone wants to admit.

Preterminated Sensor Connection

The temperature sensor uses a factory-sealed connector designed to plug into the supplied gauge harness without cutting or modifying the sensor wiring.

The gauge still requires basic electrical installation:

• Red wire to switched positive power
• Black wire to a clean chassis or battery ground
• Sensor installed in a compatible temperature port

A fuse should be installed in the positive power circuit unless the supplied wiring or vehicle circuit is already properly protected.

Low Current Draw

The gauge draws approximately 0.3 amps during operation. This makes it suitable for continuous monitoring while the vehicle is running without placing a significant load on a healthy charging system.

The gauge should normally be connected to switched power so it turns off with the ignition. A 0.3-amp load may be small, but left connected continuously, it can still discharge a battery over time. Physics remains annoyingly consistent.

Product Specifications

• Brand: JJCOCO
• Manufacturer part number: WTG-02-BL
• Gauge type: Digital temperature gauge
• Gauge diameter: 2 inches / 52mm
• Temperature range: 32–300°F
• Celsius range: 0–150°C
• Display type: Digital LED
• Warning alarm: User adjustable
• Warning behavior: Flashing display
• Setting memory: Automatic save
• Peak recall: Yes
• Sensor thread: 1/8-inch NPT
• Current draw: Approximately 0.3A
• Recommended operating voltage: 12V DC
• Mounting options: Bracket or adhesive backing
• Application: Compatible automotive and marine temperature monitoring

What’s Included

• One digital temperature gauge
• One 1/8-inch NPT temperature sensor
• One mounting bracket
• One adhesive mounting backing
• Sensor connector and wiring

A vehicle-specific adapter, inline radiator-hose adapter, fuse holder or additional wiring may be required.

Installation Notes

Install the 1/8-inch NPT sender in a port where it remains in contact with the coolant or compatible fluid being monitored.

Possible coolant-sender locations include:

• Cylinder head
• Intake manifold
• Thermostat housing
• Coolant outlet
• Engine block
• Inline radiator-hose adapter

Before installation:

• Disconnect vehicle power.
• Allow the engine and cooling system to cool completely.
• Verify the sender-port thread size.
• Use a compatible adapter if required.
• Connect red to switched positive power.
• Connect black to a clean ground.
• Protect the power circuit with an appropriate fuse.
• Route wiring away from exhaust components.
• Keep wiring clear of belts, pulleys and cooling fans.
• Bleed trapped air from the cooling system.
• Inspect every opened connection for leaks.
• Configure and test the warning threshold before driving.

Do not connect the gauge to AC power. Do not connect it directly to a 24V system unless the included instructions explicitly confirm 24V operation.

For more information about coolant-temperature sensors, read our guide explaining how an engine coolant temperature sensor works.

Frequently Asked Questions

What temperature range does the gauge measure?

The gauge measures temperatures from 32°F to 300°F or 0°C to 150°C.

Can I customize the overheating warning?

Yes. Press and hold the WARN button, then use WARN to increase or PEAK to decrease the warning temperature. The setting saves automatically after approximately three seconds.

What does the PEAK button do?

The PEAK button displays the highest recorded temperature, making it easier to identify temperature spikes that occurred while driving.

Is this gauge compatible with 24V vehicles?

The available product information is contradictory. One specification lists 12V/24V compatibility, while the installation warning states that only 12V DC should be used. Treat it as a 12V gauge unless the included manual confirms otherwise.

Is the sender included?

Yes. The kit includes a temperature sender with a 1/8-inch NPT mounting thread.

Is installation completely plug-and-play?

The sender uses a preterminated connector, but power and ground wiring are still required. Some vehicles may also need a sender adapter.

Can it monitor transmission or hydraulic-fluid temperature?

The sensor may be suitable for compatible oil and hydraulic applications, provided the temperature range, thread size, pressure exposure and sensor materials are appropriate. Verify compatibility before installing it outside an engine cooling system.

Is the gauge waterproof?

The listing describes it as water resistant, but no certified IP rating is provided. Protect the gauge and electrical connections from direct water exposure, especially in marine or open-cockpit installations.

Does the alarm automatically shut down the engine?

No. The alarm provides a flashing visual warning. The driver must reduce load, stop safely or shut down the engine when necessary.

What should I do if the alarm activates?

Watch whether the temperature stabilizes or continues rising. If it continues to climb, coolant escapes or steam appears, pull over safely and shut the engine off. Never open a hot, pressurized cooling system.

Read our guide on how to deal with an overheating engine before continuing to operate the vehicle.

Smarter Temperature Monitoring

The JJCOCO digital temperature gauge adds two valuable features beyond a basic coolant gauge: an adjustable warning threshold and peak-temperature recall.

Combined with its 32–300°F range, high-contrast LED display, low current draw and included 1/8-inch NPT sensor, it provides a practical monitoring solution for compatible cars, trucks, RVs, performance vehicles and marine applications.