160° Thermostat Kit – Fits MerCruiser 4.3L, 5.0L, 5.7L, 7.4L V6/V8 Engines (Replaces 807252Q5)
160° Thermostat Kit – Fits MerCruiser 4.3L, 5.0L, 5.7L, 7.4L V6/V8 Engines (Replaces 807252Q5) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
160° Thermostat Kit – Fits MerCruiser 4.3L, 5.0L, 5.7L, 7.4L V6/V8 ...
Product Details
This 160° Thermostat Kit – Fits MerCruiser 4.3L, 5.0L, 5.7L, 7.4L V6/V8 Engines (Replaces 807252Q5) is designed for MerCruiser inboard and sterndrive engines with V6 and V8 configurations that require a 160° thermostat. It is primarily for 4.3L, 5.0L, 5.7L, and 7.4L/8.2L engines from 1987 and newer.
This kit serves as a direct replacement for MerCruiser part numbers 807252Q5, 807252T8, 807252T5, as well as aftermarket equivalents like Sierra 18-3647 and Engineered Marine Products 807252Q5.
- Engineered for direct replacement installation.
- Maintains optimal engine temperature for raw water cooled systems.
- Includes thermostat, plastic housing sleeve, and all necessary gaskets for a complete service.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| MerCruiser | 807252Q5 |
| MerCruiser | 807252T8 |
| MerCruiser | 807252T5 |
| Sierra | 18-3647 |
| Engineered Marine Products | 807252Q5 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| MerCruiser | 4.3L, 4.3LX, 4.3LXH Alpha | 190 | 4-Stroke | 1996–1997 | 807252Q5 | Serial Range: 0F601127-0K999999 |
| MerCruiser | 4.3L, 4.3LX, 4.3LXH Bravo | 190 | 4-Stroke | 1996–1997 | 807252Q5 | Serial Range: 0F601127-0K999999 |
| MerCruiser | 4.3L, 4.3LX GM | 190 | 4-Stroke | 1993–1995 | 807252Q5 | Serial Range: 0F000878-0F601126 |
| MerCruiser | 4.3L, 4.3LH, 4.3EFI Alpha | 190 | 4-Stroke | 1998 & Up | 807252Q5 | Serial Range: 0L010044 & Up |
| MerCruiser | 4.3L, 4.3LH, 4.3EFI Bravo | 190 | 4-Stroke | 1998 & Up | 807252Q5 | Serial Range: 0L010044 & Up |
| MerCruiser | 5.0L, 5.0LX GM | 220 | 4-Stroke | 1987–1995 | 807252Q5 | Serial Range: 0B525982-0F600999 |
| MerCruiser | 5.0L, 5.0EFI Alpha | 220 | 4-Stroke | 1998 & Up | 807252Q5 | Serial Range: 0L012052 & Up |
| MerCruiser | 5.0L, 5.0EFI Bravo | 220 | 4-Stroke | 1998 & Up | 807252Q5 | Serial Range: 0L012052 & Up |
| MerCruiser | 5.7L, 5.7LX GM | 260 | 4-Stroke | 1987–1995 | 807252Q5 | Serial Range: 0B525982-0F600999 |
| MerCruiser | 5.7L GM Alpha | 260 | 4-Stroke | 1995–1997 | 807252Q5 | Serial Range: 0F225560-0K999999 |
| MerCruiser | 5.7L GM Bravo | 260 | 4-Stroke | 1995–1997 | 807252Q5 | Serial Range: 0F225560-0K999999 |
| MerCruiser | 5.7L, 5.7EFI GM Alpha | 260 | 4-Stroke | 1998 & Up | 807252Q5 | Serial Range: 0L010037 & Up |
| MerCruiser | 5.7L, 5.7EFI GM Bravo | 260 | 4-Stroke | 1998 & Up | 807252Q5 | Serial Range: 0L010037 & Up |
| MerCruiser | 5.7L M IE | 260 | 4-Stroke | 1994–1997 | 807252Q5 | Serial Range: 0F025000-0K999999 |
| MerCruiser | 5.7L M IE | 260 | 4-Stroke | 1998 & Up | 807252Q5 | Serial Range: 0L002003 & Up |
| MerCruiser | 5.7L Ski | 260 | 4-Stroke | 1987–1998 | 807252Q5 | Serial Range: 0B514627 & Up |
| MerCruiser | 262 MAG Alpha | 260 | 4-Stroke | 1996–1997 | 807252Q5 | Serial Range: 0F803800-0K999999 |
| MerCruiser | 262 MAG Bravo | 260 | 4-Stroke | 1996–1997 | 807252Q5 | Serial Range: 0F803800-0K999999 |
| MerCruiser | 350 MAG | 300 | 4-Stroke | 1987–1997 | 807252Q5 | Serial Range: 0B525982-0F600999 |
| MerCruiser | 350 MAG EFI Ski | 300 | 4-Stroke | 1994–1997 | 807252Q5 | Serial Range: 0D505450-0K999999 |
| MerCruiser | 350 MAG MPI / M IE | 300 | 4-Stroke | 1998 & Up | 807252Q5 | Serial Range: 0L010019 & Up |
| MerCruiser | 350 MAG MPI Ski | 300 | 4-Stroke | 1995–1998 | 807252Q5 | Serial Range: 0F350583 & Up |
| MerCruiser | 350 MAG Ski | 300 | 4-Stroke | 1991–1997 | 807252Q5 | Serial Range: 0D505450-0K999999 |
| MerCruiser | 454 MAG MCM / Ski | 385 | 4-Stroke | 1995–1997 | 807252Q5 | Serial Range: 0F305000-0K999999 |
| MerCruiser | 7.4L, 7.4LX GM | 330 | 4-Stroke | 1996–1997 | 807252Q5 | Serial Range: 0F352000-0K999999 |
| MerCruiser | 7.4L M IE | 330 | 4-Stroke | 1989–1997 | 807252Q5 | Serial Range: 0C391564-0K999999 |
| MerCruiser | 7.4L MPI / TBI | 330 | 4-Stroke | 1995–1998 | 807252Q5 | Serial Range: 0F563052 & Up |
| MerCruiser | 8.2L M IE | 380 | 4-Stroke | 1993–1996 | 807252Q5 | Serial Range: 0D857200-0F819619 |
| MerCruiser | 8.2L MPI / M IE | 380 | 4-Stroke | 1996 & Up | 807252Q5 | Serial Range: 0F819620 & Up |
| MerCruiser | 502 EFI / MPI MCM | 415 | 4-Stroke | 1993–1997 | 807252Q5 | Serial Range: 0F802600-0K999999 |
| MerCruiser | 502 MAG MPI | 415 | 4-Stroke | 1998 & Up | 807252Q5 | Serial Range: 0L017000 & Up |
| MerCruiser | Scorpion Ski | 4-Stroke | 1996–1998 | 807252Q5 | Serial Range: 0F800000 & Up |
Technical Specs
- Product Type
- Thermostat Kit
- Thermostat Temperature
- 160°F (71°C)
- Installation
- Direct replacement
- Dimensions
- Height: 10.0 in; Width: 11.0 in; Length: 11.0 in
- Weight
- 0.07 kg (0.15 lb)
What’s in the Box
- 1 x Thermostat (807252T2/8072522/8052732)
- 1 x O-ring (25-30224/25-27018)
- 1 x Gasket (27-331792/27-331791)
- 1 x Gasket (27-41812/27-09556)
- 1 x Gasket (27-47510)
- 1 x Gasket (27-33918)
- 1 x Gasket (27-530451/27-53045/27-33179)
- 1 x Plastic Housing Sleeve (23-806922)
Installation Notes
- Ensure the engine is cool and disconnect the battery.
- Drain the engine coolant/raw water from the system to a level below the thermostat housing.
- Locate and remove the thermostat housing. Note the orientation of hoses before disconnecting.
- Remove the old thermostat, sleeve, and gaskets. Take note of the thermostat's orientation.
- Thoroughly clean the mating surfaces of the housing and engine block, removing any old gasket material or sealant.
- Install the new plastic sleeve and thermostat in the correct orientation.
- Place the new gaskets on the housing, applying a marine-grade sealant if recommended by the engine manufacturer.
- Reinstall the thermostat housing and tighten the bolts to the manufacturer's specified torque.
- Reconnect hoses and refill the cooling system.
- Reconnect the battery, start the engine, and check for leaks. Monitor the temperature gauge to ensure it warms up to and holds the correct temperature.
Troubleshooting & FAQ
How do I know if this thermostat kit will fit my engine?
The best way to confirm fitment is to check your engine model, year, and serial number against our compatibility table. Cross-referencing your old part number with the numbers in our Part Number Matrix is also a reliable method.
What are the signs of a faulty thermostat?
Common symptoms include the engine overheating (running above its normal temperature range) or running too cold (not reaching operating temperature). An erratic temperature gauge or visible coolant leaks around the housing can also indicate a problem.
When should I replace my engine's thermostat?
Thermostats should be replaced as part of regular preventative maintenance every 3-5 years, especially in saltwater environments. They should also be replaced immediately if you notice any signs of failure.
Why is a 160°F thermostat used in marine engines?
A 160°F thermostat is standard for raw-water cooled marine engines because it allows the engine to reach a temperature high enough for efficient combustion but low enough to prevent salt and mineral buildup, which can occur at higher temperatures.
What is the function of the plastic sleeve?
The plastic sleeve helps to properly position the thermostat within the housing and ensures that water flows correctly through the thermostat assembly for accurate temperature regulation.
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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