Thermostat Service Kit – Fits Mercury/Mariner V6 & V8 175HP-300HP (Replaces 8M0162139, 8M0137816)
Thermostat Service Kit – Fits Mercury/Mariner V6 & V8 175HP-300HP (Replaces 8M0162139, 8M0137816) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
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Thermostat Service Kit – Fits Mercury/Mariner V6 & V8 175HP-300...
Thermostat Service Kit – Fits Mercury/Mariner V6 & V8 175HP-300HP (Replaces 8M0162139, 8M0137816) is backordered and will ship as soon as it is back in stock.
Product Details
This Thermostat Service Kit – Fits Mercury/Mariner V6 & V8 175HP-300HP is essential for maintaining your engine's cooling system at the correct operating temperature. It is designed for Mercury/Mariner 3.4L V6 and 4.6L V8 4-Stroke outboards from 2013 and up, with serial numbers 2B529482 and higher.
This kit is a direct replacement for Mercury part numbers 8M0162139 and 8M0137816, and also serves as an interchange for Quicksilver 8M0162139 and JLM Marine 8M0162139.
- Engineered for direct-fit installation.
- Maintains a precise operating temperature of 60°C (140°F).
- A critical component for the Mercury outboard cooling system.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number | Notes |
|---|---|---|
| Mercury | 8M0162139 | Supersedes 8M0137816 |
| Mercury | 8M0137816 | Superseded by 8M0162139 |
| Quicksilver | 8M0162139 | OEM equivalent |
| JLM Marine | 8M0162139 | Aftermarket replacement |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For Mercury & Mariner models, ensure your engine's serial number is 2B529482 or higher for most models, or check the specific serial number ranges noted in the table.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Mercury | V6 3.4L | 175 | 4-Stroke | 2013–Up (SN 2B529482+) | 8M0162139 | Supersedes 8M0137816 |
| Mercury | V6 3.4L Pro XS | 175 | 4-Stroke | 2013–Up (SN 2B529482+) | 8M0162139 | Supersedes 8M0137816 |
| Mercury | V6 3.4L | 200 | 4-Stroke | 2013–Up (SN 2B529482+) | 8M0162139 | Supersedes 8M0137816 |
| Mercury | V6 3.4L SeaPro | 200 | 4-Stroke | 2013–Up (SN 2B529482+) | 8M0162139 | Supersedes 8M0137816 |
| Mercury | APEX | 200 | 4-Stroke | 2021–Up (SN 1E054353+) | 8M0162139 | Supersedes 8M0137816 |
| Mercury | V8 4.6L Pro XS | 200 | 4-Stroke | 2013–Up (SN 2B529482+) | 8M0162139 | Supersedes 8M0137816 |
| Mercury | V6 3.4L | 225 | 4-Stroke | 2013–Up (SN 2B529482+) | 8M0162139 | Supersedes 8M0137816 |
| Mercury | V8 4.6L Pro XS | 225 | 4-Stroke | 2013–Up (SN 2B529482+) | 8M0162139 | Supersedes 8M0137816 |
| Mercury | V8 4.6L SeaPro | 225 | 4-Stroke | 2013–Up (SN 2B529482+) | 8M0162139 | Supersedes 8M0137816 |
| Mercury | V8 4.6L | 250 | 4-Stroke | 2013–Up (SN 2B529482+) | 8M0162139 | Supersedes 8M0137816 |
| Mercury | V8 4.6L Pro XS | 250 | 4-Stroke | 2013–Up (SN 2B529482+) | 8M0162139 | Supersedes 8M0137816 |
| Mercury | V8 4.6L SeaPro | 250 | 4-Stroke | 2013–Up (SN 2B529482+) | 8M0162139 | Supersedes 8M0137816 |
| Mercury | V8 4.6L Verado | 250 | 4-Stroke | 2013–Up (SN 2B529482+) | 8M0162139 | Supersedes 8M0137816 |
| Mercury | V8 4.6L Racing | 250R | 4-Stroke | 2019–Up (SN 1E080500+) | 8M0162139 | Supersedes 8M0137816 |
| Mercury | V8 4.6L | 300 | 4-Stroke | 2013–Up (SN 2B529482+) | 8M0162139 | Supersedes 8M0137816 |
| Mercury | V8 4.6L Pro XS | 300 | 4-Stroke | 2013–Up (SN 2B529482+) | 8M0162139 | Supersedes 8M0137816 |
| Mercury | V8 4.6L SeaPro | 300 | 4-Stroke | 2013–Up (SN 2B529482+) | 8M0162139 | Supersedes 8M0137816 |
| Mercury | V8 4.6L Verado | 300 | 4-Stroke | 2013–Up (SN 2B529482+) | 8M0162139 | Supersedes 8M0137816 |
| Mercury | V8 4.6L Verado SeaPro | 300 | 4-Stroke | 2013–Up (SN 2B529482+) | 8M0162139 | Supersedes 8M0137816 |
| Mercury | V8 4.6L Racing | 300R | 4-Stroke | 2019–Up (SN 1E080500+) | 8M0162139 | Supersedes 8M0137816 |
| Mercury | V8 4.6L AMS Racing | 300R | 4-Stroke | 2020–Up (SN 1E081459+) | 8M0162139 | Supersedes 8M0137816 |
| Mercury | APEX | 360 | 4-Stroke | 2021–Up (SN 1E054247+) | 8M0162139 | Supersedes 8M0137816 |
Technical Specs
- Product Type
- Thermostat Service Kit
- Installation
- Direct replacement
- Fuel Type
- Gasoline
- Operating Temperature
- 60°C (140°F)
- Warranty
- 1 Year (Varies by manufacturer)
- Other Technical Attributes
- For Mercury outboard cooling system
What’s in the Box
- 1 x Thermostat Kit (8M0162139)
Installation Notes
- Disconnect the battery and allow the engine to cool completely before starting.
- Locate the thermostat housing and place a drain pan underneath. Slowly loosen the housing bolts to drain the engine coolant.
- Remove the housing, noting the orientation of the old thermostat and gaskets.
- Clean the housing and engine mounting surfaces, removing any old gasket material.
- Install the new thermostat and gaskets in the correct orientation as noted during removal.
- Reinstall the housing and tighten the bolts to the manufacturer's specified torque.
- Refill the cooling system with the appropriate coolant. Start the engine and check for leaks while it comes up to operating temperature.
Troubleshooting & FAQ
How do I confirm this kit fits my specific engine model?
Verify your engine's model, horsepower, and serial number against the compatibility table. This kit fits Mercury/Mariner V6 and V8 models (175-300HP) from 2013 and newer, with serial numbers 2B529482 and up. Certain racing and APEX models have different serial number ranges, so please check the aformentioned table carefully.
What are the signs of a failing thermostat?
Common symptoms include engine overheating, the engine not reaching its proper operating temperature (running too cool), erratic temperature gauge readings, or coolant leaks from the thermostat housing area.
What is the 'supersedes' note in the compatibility chart?
This indicates that the part number 8M0162139 is the new, recommended replacement for the older part number 8M0137816. You can confidently use this kit if your engine originally called for the older part number.
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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