Water Temperature Sender – Fits Mercury/Mercruiser, OMC, Crusader (Replaces Mercury 97258A1, 97258, 34625, FI6900152, FI6900198, Sierra 18-5898, Rldym 171960)
Water Temperature Sender – Fits Mercury/Mercruiser, OMC, Crusader (Replaces Mercury 97258A1, 97258, 34625, FI6900152, FI6900198, Sierra 18-5898, Rldym 171960) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
Orders are typically processed within 1–2 business days.
U.S. orders usually arrive within 6–15 days, depending on stock location and destination.
International delivery times may vary due to customs processing.
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Water Temperature Sender – Fits Mercury/Mercruiser, OMC, Crusader (...
Water Temperature Sender – Fits Mercury/Mercruiser, OMC, Crusader (Replaces Mercury 97258A1, 97258, 34625, FI6900152, FI6900198, Sierra 18-5898, Rldym 171960) is backordered and will ship as soon as it is back in stock.
Product Details
This high-quality Water Temperature Sender is engineered for a broad range of marine engines, providing reliable temperature data to your vessel's gauge. It is designed to fit Mercury/Mercruiser sterndrive (MCM) and inboard (MIE) 4-cylinder, V6, and V8 engines, as well as various OMC and Crusader models. With an operating range up to 240°F (115°C), it is a crucial component for preventing engine overheating.
This unit is a direct interchange for Mercury part numbers 97258A1, 97258, 34625, FI6900152, FI6900198; Sierra 18-5898; and Rldym 171960.
- Engineered for direct replacement with no modifications required.
- Features a single electrical terminal (10-32 stud) for a secure connection.
- Constructed from a durable metal alloy to withstand harsh marine environments.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury | 97258A1 |
| Mercury | 97258 |
| Mercury | 34625 |
| Mercury | FI6900152 |
| Mercury | FI6900198 |
| Sierra | 18-5898 |
| Rldym | 171960 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
Mercury/Mercruiser: Fits many 4-cylinder, V6, and V8 sterndrive (MCM) and inboard (MIE) engines, typically in the 120–225 HP range.
OMC & Crusader: Compatible with various V6 and V8 inboard and sterndrive engines. As applications vary, confirm fitment by cross-referencing your original part number.
| Brand | Model | Rated HP | Stroke | OEM Part No. | Notes |
|---|---|---|---|---|---|
| Mercruiser | 4-cylinder MCM | 120-225 | 4-Stroke | 97258A1 | For sterndrive engines |
| Mercruiser | V6 MCM | 120-225 | 4-Stroke | 97258A1 | For sterndrive engines |
| Mercruiser | V8 MCM | 120-225 | 4-Stroke | 97258A1 | For sterndrive engines |
| Mercruiser | V6 MIE | 120-225 | 4-Stroke | 97258A1 | For inboard engines |
| Mercruiser | V8 MIE | 120-225 | 4-Stroke | 97258A1 | For inboard engines |
| OMC | Inboard engines | 4-Stroke | Compatible with various models | ||
| OMC | Sterndrive engines | 4-Stroke | Compatible with various models | ||
| Crusader | V6 engines | 4-Stroke | |||
| Crusader | V8 engines | 4-Stroke |
Technical Specs
- Product Type
- Water Temperature Sender/Sensor
- Installation
- Direct replacement, no modifications required
- Connection
- Single electrical terminal (10-32 stud)
- Housing Material
- Metal alloy
- Dimensions
- Length: 55.4 mm (2.18 in), Width: 30 mm (1.18 in), Height: 30 mm (1.18 in)
- Weight
- 0.077 kg (0.17 lbs)
- Fitting Type
- Threaded
- Thread Size
- 1/2" - 14 NPT
- Operating Temperature
- Range up to 240°F (115°C)
- Other Technical Attributes
- DS range temperature sender
What’s in the Box
- 1 x Temperature Sender (97258A1/171960)
Installation Notes
- Disconnect the boat's negative battery terminal before beginning work.
- Locate the existing water temperature sender, typically on the engine block or thermostat housing.
- Place a suitable container underneath to catch any draining coolant.
- Carefully unplug the electrical connector from the sender.
- Using the correct size wrench, unscrew and remove the old sender from the engine.
- Apply a small amount of thread sealant to the threads of the new sender to prevent leaks.
- Thread the new sender in by hand, then tighten it to the manufacturer's specified torque. Do not overtighten.
- Reconnect the electrical connector securely onto the new sender's terminal.
- Reconnect the negative battery terminal.
- Top off the engine coolant to the proper level.
- Start the engine and carefully inspect for any leaks around the new sender.
- Monitor the temperature gauge to ensure it is providing an accurate reading.
Troubleshooting & FAQ
How do I know if my temperature sender is failing?
Common signs of a faulty sender include an inoperative temperature gauge, a gauge that reads abnormally high or low, or erratic and sudden fluctuations in the temperature reading. Verifying the sender with a multimeter can confirm a failure.
What is the difference between a temperature sender and a temperature switch?
A temperature sender (like this part) provides a variable resistance signal to a gauge, showing a range of temperatures. A temperature switch is a simple on/off device that activates an alarm or light only when a specific temperature threshold is crossed.
Why is my temperature gauge reading incorrectly after installation?
First, ensure the electrical connection is clean and secure. Second, confirm you are using a compatible temperature gauge; this sender is designed for standard American resistance (DS range) gauges. A mismatch between the sender and gauge will result in inaccurate readings.
Can this sender be used for an oil temperature reading?
While physically similar, this part is specifically calibrated for water/coolant temperature ranges. Using it for oil may result in inaccurate gauge readings, as oil temperature senders often have different resistance curves.
Is any special calibration needed after installation?
No, calibration is not required. As a direct replacement, it is designed to work with your existing compatible gauge system right out of the box, provided the gauge itself is functional.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.
Shipping speed & cost?
We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.
Warranty & returns?
Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.
Safety & Important Info
- Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement, not an OEM component.
- Professional installation is recommended for safety and performance.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
- Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
- Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.
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