Thermostat Service Kit 160°F – Fits MerCruiser V6 & V8 (Replaces 807252Q5)
Thermostat Service Kit 160°F – Fits MerCruiser V6 & V8 (Replaces 807252Q5) is backordered and will ship as soon as it is back in stock.
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Worry-free returns
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Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Thermostat Service Kit 160°F – Fits MerCruiser V6 & V8 (Replace...
Product Details
This Thermostat Service Kit 160°F – Fits Mercruiser V6 & V8 Marine Engines (Replaces 807252Q5) is designed for MerCruiser V6 and V8 gasoline engines (4.3L, 5.0L, 5.7L, 7.4L, 8.2L) manufactured between 1987 and 2016. It is engineered for models requiring a standard 160°F (71°C) thermostat for standard (raw water) cooling systems.
This kit serves as a direct replacement for multiple OEM and aftermarket part numbers, including Mercury 807252Q5, 807252T5, Sierra 18-3647, and GLM 13101, ensuring broad compatibility.
- Engineered as a direct-fit replacement for easy installation.
- Includes a new thermostat, housing sleeve, o-ring, and all necessary gaskets.
- Designed for standard (raw water) cooling systems. Not recommended for high-performance engines.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury | 807252Q5 |
| Mercury | 807252T5 |
| Mercury | 807252T8 |
| Mercury | 8052732 |
| Mercury | 8072522 |
| Mercury | 807252T2 |
| Mercury | 8M0091470 |
| Mercury | 8M0109441 |
| Sierra | 18-3647 |
| GLM | 13101 |
| Mallory | 9-43157 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For MerCruiser models, this kit fits a wide range of V6 and V8 engines from 1987 onwards with standard cooling systems.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| MerCruiser | 4.3L V6 | Multiple | 4-Stroke | 1987–2016 | 807252Q5 | Standard cooling |
| MerCruiser | 5.0L V8 | Multiple | 4-Stroke | 1987–2016 | 807252Q5 | Standard cooling |
| MerCruiser | 5.7L V8 | Multiple | 4-Stroke | 1987–2016 | 807252Q5 | Standard cooling |
| MerCruiser | 7.4L V8 | Multiple | 4-Stroke | 1987–2016 | 807252Q5 | Standard cooling |
| MerCruiser | 8.2L V8 | Multiple | 4-Stroke | 1987–2016 | 807252Q5 | Standard cooling |
Technical Specs
- Product Type
- Thermostat Service Kit
- Temperature Rating
- 160°F (71°C)
- Compatible Engines
- V6 & V8 MerCruiser engines (standard cooling)
- Housing Material
- Metal with plastic sleeve
- Installation
- Direct replacement
- Kit Components
- Thermostat, O-ring, housing sleeve, multiple gaskets
- Weight
- 50g (1.76 oz)
- Warranty
- 90 days (varies by retailer)
- Manufacturer
- Mercury Marine (Quicksilver)
What’s in the Box
- 1 x 160°F Thermostat (807252T2)
- 1 x O-ring Seal (25-30224)
- 1 x Housing Sleeve (23-806922/806922)
- 1 x Gasket (27-33179-2)
- 1 x Gasket (27-47510)
- 1 x Gasket (27-48818-1)
- 1 x Gasket (27-33918)
Installation Notes
- Ensure the engine is completely cool and disconnect the battery for safety.
- Drain the engine coolant into a suitable container. Follow your engine manual for specific draining procedures.
- Locate the thermostat housing and carefully remove the bolts or nuts. Note the orientation of the housing.
- Remove the old thermostat, sleeve, and gaskets. Take care not to drop debris into the engine passages.
- Thoroughly clean the gasket mating surfaces on both the engine and the housing.
- Install the new thermostat, gaskets, and sleeve as provided in the kit. Ensure the thermostat is oriented correctly (usually with the spring side facing the engine).
- Reinstall the housing and tighten the bolts to the manufacturer-specified torque in a crisscross pattern.
- Refill the cooling system with the appropriate coolant. Run the engine and check for leaks and proper operating temperature.
Troubleshooting & FAQ
How do I know if this thermostat fits my engine?
This kit fits most MerCruiser V6 and V8 engines (4.3L to 8.2L) made from 1987 to 2016 with standard raw water cooling. The best way to confirm is to match your existing part number to one of the equivalents listed in our Part Number Matrix.
What are the signs of a failing thermostat?
Common symptoms include engine overheating, running too cool (not reaching operating temperature), erratic temperature gauge readings, and visible coolant leaks around the thermostat housing.
Why does the kit include multiple gaskets?
This kit is designed to cover a wide range of engine variations over many years. Different models used different thermostat housing and manifold configurations, so we include multiple gasket shapes to ensure you have the correct one for your specific application.
Is this kit suitable for high-performance engines?
No, this 160°F thermostat kit is designed for standard, stock engines. High-performance or modified engines often require different temperature ratings and specialized components. Using this kit on such engines is not recommended.
What is the difference between a 140°F and 160°F thermostat?
A 160°F thermostat (like this one) is standard for raw water-cooled engines, helping the engine reach an efficient operating temperature while preventing salt and mineral buildup. A 140°F thermostat is typically used in freshwater or closed-cooling systems.
How often should a marine thermostat be replaced?
As a preventative measure, it is good practice to inspect your thermostat annually and replace it every 3-5 years, or immediately if you notice signs of failure. In saltwater environments, more frequent replacement may be necessary due to corrosion.
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.
Payment & Security
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