Sierra - Water Temperature Sender Dual Station 3/8"-18 NPT - SIE-18-5897
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The Sierra Marine 18-5897 Water Temperature Sender is a dual-station marine engine temperature sending unit for compatible inboard and sterndrive gauge systems. It is designed for installations where one engine temperature sender must drive two separate temperature gauges, such as a lower helm and flybridge helm. This sender uses a 3/8"-18 NPT thread, a 10-32 threaded stud terminal, and a dual-station resistance range intended for compatible marine temperature gauges.
Key Features
- Sierra part number: 18-5897
- Product code: SIE-18-5897
- Product type: Marine water temperature sender
- Gauge configuration: Dual Station / DS
- Thread size: 3/8"-18 NPT
- Terminal style: 10-32 threaded stud
- Temperature range: Up to 240°F
- Sender code: Code D
- Resistance reference: Approximately 339 ohms at 100°F and 35 ohms at 220°F
- Gauge compatibility: For compatible Teleflex, SeaStar, VeeThree, and other Code D-calibrated marine gauges
- Primary use: Engine coolant or water-temperature signal for dual-helm gauge installations
Engine Compatibility
This sender is intended for compatible marine engines using a 3/8"-18 NPT temperature sender port and a matching dual-station gauge calibration. Common application areas include GM-based marine engine packages used in:
- MerCruiser MCM sterndrive engines
- Mercury MIE inboard engines
- Volvo Penta gasoline inboard and sterndrive engines
- OMC sterndrive engines
- 4-cylinder, V6, and V8 marine engine blocks where the sender thread and gauge calibration match
Fitment must be confirmed by engine model, sender port thread, gauge type, and wiring configuration before installation.
Fitment Notice
This is a dual-station sender. It should be used only where the boat has two compatible temperature gauges reading from one sender. Single-station and dual-station senders can have different resistance curves, and installing the wrong sender can cause inaccurate temperature readings.
Before ordering, confirm the original sender part number, gauge brand, sender code, thread size, terminal style, and whether the vessel uses one helm gauge or two.
When This Part Needs Replacement
Replace the water temperature sender if the temperature gauge reads incorrectly, stays cold, pegs hot, fluctuates erratically, or does not match verified engine temperature. It should also be inspected if the sender terminal is corroded, the body is leaking, the threads are damaged, or the wiring connection is loose or contaminated.
Before replacing the sender, confirm that the gauge, wiring, ground path, and engine temperature are functioning correctly. Gauge problems can also be caused by poor grounds, damaged sender wires, incorrect gauge calibration, or actual engine cooling-system issues.
Installation Notes
Install the sender into the correct 3/8"-18 NPT temperature port using proper marine service practices. Do not overtighten the sender, as pipe-thread fittings can crack housings or distort threads. Keep the terminal clean and secure, and verify that the gauge wiring is connected to the 10-32 stud properly.
After installation, run the engine and compare gauge response against normal operating temperature. If the sender is being installed on a dual-helm vessel, confirm both gauges respond correctly and read consistently.
Alternate/Cross-Reference Part Numbers
- Sierra Marine: 18-5897
- Marisol / product code: SIE-18-5897
- Mercury / MerCruiser: 806490T
- Mercury / MerCruiser: 806490
- Mercury / MerCruiser: 97257A1
- Mercury / MerCruiser: 36525
- Mercury / MerCruiser: 22-811091
- Volvo Penta / OMC: 3853787
- Volvo Penta / OMC: 980613
- Mallory Marine: 9-42400
- Stewart Warner: 352BC-D
Cross-reference numbers should be confirmed against the engine model, gauge calibration, and sender thread before substitution.
Parts Desk Insight
The most important detail on this sender is the dual-station calibration. A sender that physically threads into the engine may still give the wrong reading if it is matched to the wrong gauge type or helm configuration. Confirm Code D / dual-station compatibility before ordering, especially on boats with both cabin and flybridge temperature gauges.
Shipping: Ships same or next day for fast Canada wide shipping. ⚓
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 3–4 business days.
Special-order items: timeline confirmed after order.
Returns & warranty
Returns & Satisfaction Guarantee
We stand firmly behind the quality of every product we sell. Your confidence matters to us — and we back it with a straightforward 30-Day Satisfaction Guarantee.
If you are not fully satisfied, you may request a return within 30 days of delivery. All returns must receive pre-approval prior to being sent back. Unauthorized returns will not be accepted.
To qualify for a return:
Item must be in new, unused condition
Product must be in its original packaging
All parts, components, hardware, manuals, and accessories must be included
Packaging must be undamaged and suitable for resale
Important:
Electronics are strictly inspected. No returns on open-box electronics. Exceptions may apply only with prior written approval. Any electronic unit that has been installed, powered, activated, or altered may not be eligible for return.
We are serious about product integrity — and equally serious about taking care of our customers. If there is ever a product issue, contact us immediately so we can make it right.
For return authorization, please contact our support team before shipping anything back.