Amega Water Temperature Gauge | Sierra 57904P

Sierra 57904P Seastar Amega Series Water Temperature Gauge | 2 in. | 120–240°F | US & Metric Scales | Single Engine

The Sierra #57904P is a 2-inch water temperature gauge from the Seastar Solutions Amega Series (formerly Teleflex). Displays coolant temperature for a single marine engine. 120–240°F range with dual US (°F) and metric (°C) scales. Black dial face with red and white graphics, ISO symbol, black near-flush bezel, white pointer, scratch-resistant curved lens, and through-dial with perimeter lighting. Optional add-on eyebrow or square bezels available separately.

Product Details:

• Part Number: 57904P (Sierra / Seastar Solutions)
• SKU: SIERRA-57904P
• Manufacturer: Sierra / Seastar Solutions (formerly Teleflex)
• Type: Water Temperature Gauge — Amega Series
• Engine Coverage: Single engine
• Diameter: 2 in.
• Temperature Range: 120–240°F
• Scales: US (°F) and metric (°C) — dual scale display
• Dial Face: Black with red and white graphics; ISO symbol
• Bezel: Black, near-flush
• Pointer: White
• Lens: Scratch-resistant curved
• Lighting: Through-dial and perimeter
• Optional Bezels: Eyebrow or square add-on bezels — sold separately
• Formerly: Teleflex gauge
• Condition: New

Additional Information

Temperature Sender Resistance — Confirm Before Ordering:

Water temperature gauge compatibility depends on matching the gauge's input resistance range to the temperature sender installed on the engine. Marine temperature senders vary by resistance specification — common ranges include 240–33 ohm and other OEM-specific sender curves. Connecting a gauge to a sender with a mismatched resistance will cause incorrect temperature readings — typically reading too high or too low relative to actual coolant temperature. Confirm the sender resistance specification for the 57904P in Seastar's gauge specification sheet and verify the resistance output of your existing engine temperature sender before ordering. Contact us at MacombMarineParts.com for sender compatibility confirmation.

120–240°F Range — Normal vs. Alarm Temperatures:

The 57904P displays coolant temperature from 120°F to 240°F. Most gasoline marine engines operate in the 160–180°F thermostat range at normal operating temperature. The upper end of the gauge range (above 200°F) represents the overheating zone — sustained readings above the engine's normal operating temperature warrant immediate investigation. The visual red and white graphics on the Amega Series dial provide clear visual differentiation between the normal operating zone and the upper temperature warning area.

Dual US and Metric Scales — ISO Symbol:

The 57904P displays temperature in both Fahrenheit (°F) and Celsius (°C) on a dual-scale dial, making it suitable for vessels with international crews or configurations requiring metric instrumentation. The ISO symbol marking confirms compliance with ISO gauge presentation standards.

Amega Series — Formerly Teleflex:

The Seastar Solutions Amega Series gauges were formerly sold under the Teleflex brand. The 57904P is the current Sierra/Seastar part number for this gauge. If you are replacing a Teleflex Amega Series water temperature gauge, the Sierra 57904P is the direct current-production equivalent.

2-Inch Gauge Diameter — Panel Cutout:

The 57904P uses a standard 2-inch gauge diameter. Verify the available panel cutout size at your helm before ordering. Optional add-on eyebrow or square bezels are available separately for different panel styles or to conceal cutout edges on older panels.

Installation Notes:

• Confirm temperature sender resistance range matches gauge specification before ordering
• Verify 2 in. panel cutout availability at helm before ordering
• Single engine only — one gauge required per engine for multi-engine installations
• Refer to Seastar Amega Series installation instructions for wiring and lighting connection
• Optional add-on bezels available separately — contact us for options

Frequently Asked Questions

1. What temperature sender resistance does this gauge require?
Confirm the sender resistance specification for the 57904P in Seastar's gauge specification sheet before ordering. Mismatched sender resistance causes incorrect temperature readings. Contact us at MacombMarineParts.com for sender compatibility help.

2. What is the normal operating temperature range for a marine engine?
Most gasoline marine engines operate at 160–180°F at normal thermostat temperature. The 57904P's 120–240°F range covers both warm-up and overheating zones. Consult your engine service manual for the specified normal operating temperature range for your engine.

3. Is this gauge compatible with my engine?
Compatibility is determined by the temperature sender resistance installed on your engine. Confirm the sender resistance specification matches the 57904P before ordering. Contact us at MacombMarineParts.com with your engine make, model, and year for assistance.

4. Is this the same gauge as the old Teleflex Amega Series water temperature gauge?
Yes — the Seastar Solutions Amega Series is the direct successor to the Teleflex Amega Series. The Sierra 57904P is the current part number for this gauge.

5. Does this gauge display both Fahrenheit and Celsius?
Yes — the 57904P has dual US (°F) and metric (°C) scales on the same dial face, with ISO symbol marking.