Water Temperature Sender for MerCruiser, OMC/Volvo Penta, Indmar & Crusader Engines – 1/2-14 NPT
Water Temperature Sender for MerCruiser, OMC/Volvo Penta, Indmar & Crusader Engines – 1/2-14 NPT is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
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Water Temperature Sender for MerCruiser, OMC/Volvo Penta, Indmar &a...
Water Temperature Sender for MerCruiser, OMC/Volvo Penta, Indmar & Crusader Engines – 1/2-14 NPT is backordered and will ship as soon as it is back in stock.
Product Details
This aftermarket Water Temperature Sender is designed to provide a temperature signal to a compatible marine engine gauge. It is listed for MerCruiser stern-drive applications and for selected OMC/Volvo Penta sterndrive, Indmar, and Crusader applications. The sender uses a 1/2-14 NPT threaded fitting for installation where the original sender has the same thread and electrical configuration.
For OMC/Volvo Penta applications, the listed fitment covers 1968–1993 sterndrive engines with four-cylinder engines rated at 120–140 HP, V6 engines rated at 150–165 HP, and V8 GM engines rated at 170–225 HP. It is also listed for Indmar four-cylinder, V6, and V8 engines. Always compare the original sender, thread, connector, and manufacturer part number before ordering.
- Replacement water temperature sender for compatible marine engines.
- 1/2-14 NPT threaded fitting.
- Single electrical terminal connection for the compatible gauge circuit.
- Direct-replacement format when the original part and application match.
- Aftermarket replacement; not manufactured by Mercury, MerCruiser, OMC, Volvo Penta, Indmar, or Crusader.
Part Number Matrix
The following manufacturer and aftermarket references are listed for identification and cross-reference purposes. A number match should be confirmed against the complete engine application and original part.
| Brand or Reference | Part Number |
|---|---|
| MerCruiser | 97258A1 |
| MerCruiser | 97258 |
| MerCruiser | 34625 |
| MerCruiser | FI6900152 |
| MerCruiser | FI6900198 |
| MerCruiser | 171960 |
| OMC/Volvo Penta | 3852059 |
| OMC/Volvo Penta | 0171960 |
| OMC/Volvo Penta | 0509448 |
| OMC/Volvo Penta | 0778412 |
| Indmar | S645001 |
| Indmar | 645001 |
| Crusader | 700427 |
| Sierra Marine aftermarket reference | 18-5898 |
| OBR aftermarket reference | MR-584 |
| Mallory Marine aftermarket reference | 9-42401 |
Engine & Model Compatibility
Fitment conditions must be kept together. Confirm the engine brand, drive type, model, year, horsepower, and original sender number before installation.
| Brand or Application | Engine or Drive Condition | Year | Rated HP | Stroke | Reference |
|---|---|---|---|---|---|
| OMC / Volvo Penta | Sterndrive, 4-cylinder | 1968–1993 | 120–140 HP | Not specified | 3852059, 0171960, 0509448, 0778412, 171960 |
| OMC / Volvo Penta | Sterndrive, V6 | 1968–1993 | 150–165 HP | Not specified | 3852059, 0171960, 0509448, 0778412, 171960 |
| OMC / Volvo Penta | Sterndrive, V8 GM | 1968–1993 | 170–225 HP | Not specified | 3852059, 0171960, 0509448, 0778412, 171960 |
| Indmar | 4-cylinder, V6, or V8 | Not specified | Not specified | Not specified | S645001, 645001 |
| MerCruiser | Stern-drive / out-drive applications listed for this sender family | Not specified | Not specified | Not specified | 97258A1, 97258, 34625, FI6900152, FI6900198 |
| Crusader | Application associated with the listed temperature sender reference | Not specified | Not specified | Not specified | 700427 |
Technical Specifications
- Product Type
- Water temperature sender
- Application
- Marine engine coolant or water temperature gauge circuit
- Installation
- Threaded replacement installation when the original application matches
- Thread Size
- 1/2-14 NPT
- Electrical Connection
- Single-terminal sender connection
- Product Status
- Aftermarket replacement; not an OEM component
What's in the Box
- 1 x Water Temperature Sender
Installation Notes
- Allow the engine to cool completely and disconnect the negative battery cable.
- Locate the existing water temperature sender on the engine, thermostat housing, or specified sender port.
- Place an appropriate container beneath the sender location if coolant or water may drain during removal.
- Disconnect the electrical lead from the original sender.
- Remove the original sender using the correct wrench. Avoid damaging the surrounding housing or threads.
- Compare the replacement sender's thread, terminal, and physical configuration with the original part.
- Apply a suitable marine-rated thread sealant if required by the engine manufacturer's instructions. Keep sealant away from the electrical terminal.
- Install the new sender by hand to prevent cross-threading, then tighten it to the manufacturer's specified torque. Do not overtighten.
- Reconnect the electrical lead and the negative battery cable.
- Restore the coolant or water level as required by the engine manufacturer's service procedure.
- Run the engine carefully, check for leaks, and verify that the gauge responds normally.
Troubleshooting & FAQ
How do I know if the temperature sender is failing?
Common symptoms include an inoperative gauge, an unusually high or low reading, or an unstable reading. Before replacing the sender, inspect the wiring, terminal, gauge, engine ground, and cooling system. Test the sender according to the engine or gauge manufacturer's procedure.
What is the difference between a temperature sender and a temperature switch?
A temperature sender supplies a temperature signal to a gauge, while a temperature switch generally opens or closes an electrical circuit at a specified threshold for an alarm or warning circuit. Confirm which device your engine requires before ordering.
Why is the gauge reading incorrectly after installation?
Check that the sender matches the gauge system, that the terminal is clean and secure, and that the engine has a good electrical ground. A sender and gauge with incompatible resistance characteristics can produce an inaccurate reading even when the thread fits.
Can this sender be used for oil temperature?
This listing is for a water temperature sender. Do not use it for oil temperature unless the engine or gauge manufacturer specifically confirms that the sender's calibration and application are suitable.
Does this sender require calibration?
No separate calibration is normally required when the sender is correctly matched to the engine and gauge system. Verify operation after installation and follow the engine manufacturer's testing procedure if the reading is abnormal.
Is this an OEM part?
No. This is an aftermarket replacement sender. The listed manufacturer and aftermarket numbers are provided only as application and identification references.
Safety & Important Information
- Verify the complete engine application and original sender number before purchase.
- Do not rely on a thread-size match alone; connector type, calibration, and engine application must also match.
- Work only on a cool engine and follow the engine manufacturer's service instructions.
- Professional installation is recommended when access is difficult or the cooling system must be opened.
About Sea Sierra
- Marine Replacement Parts — We supply aftermarket components for common marine repair and maintenance applications.
- Application-Focused Information — Product references and fitment conditions are provided to help customers compare the original part before ordering.
- Support for Correct Selection — Confirm the engine model, year, drive type, and original part number when application details vary.
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