160°F Thermostat Service Kit for MerCruiser 4.3L–8.2L Stern Drive Engines – Replaces 807252Q5, 807252T8
160°F Thermostat Service Kit for MerCruiser 4.3L–8.2L Stern Drive Engines – Replaces 807252Q5, 807252T8 is backordered and will ship as soon as it is back in stock.
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160°F Thermostat Service Kit for MerCruiser 4.3L–8.2L Stern Drive E...
160°F Thermostat Service Kit for MerCruiser 4.3L–8.2L Stern Drive Engines – Replaces 807252Q5, 807252T8 is backordered and will ship as soon as it is back in stock.
Product Details
This 160°F (71°C) Thermostat Service Kit is designed for selected MerCruiser stern drive and inboard marine engines with 4.3L, 5.0L, 5.7L, 7.4L, or 8.2L engine configurations. It provides the thermostat, sealing components, and thermostat housing sleeve needed for a thermostat service when the application matches the listed references.
The kit is intended to replace applications using Mercury references 807252Q5 and 807252T8. Sierra reference 18-3647 is also associated with this thermostat kit application.
- 160°F (71°C) thermostat service kit.
- For selected MerCruiser 4.3L, 5.0L, 5.7L, 7.4L, and 8.2L engines.
- Includes the thermostat, O-ring, housing sleeve, and specified gaskets.
- Match the thermostat reference and included components with your existing application before ordering.
Part Number Matrix
Use these documented references to compare the application with the part being replaced. A reference number alone does not confirm fitment for every engine configuration.
| Brand or Source | Reference | Application |
|---|---|---|
| Mercury | 807252Q5 | Replacement reference |
| Mercury | 807252T8 | Replacement reference |
| Sierra | 18-3647 | Thermostat kit reference |
Engine Compatibility
This listing covers the following MerCruiser engine displacements:
| Brand | Engine Displacement | Thermostat Rating | Notes |
|---|---|---|---|
| MerCruiser | 4.3L | 160°F (71°C) | Confirm the existing thermostat and gasket arrangement. |
| MerCruiser | 5.0L | 160°F (71°C) | Confirm the existing thermostat and gasket arrangement. |
| MerCruiser | 5.7L | 160°F (71°C) | Confirm the existing thermostat and gasket arrangement. |
| MerCruiser | 7.4L | 160°F (71°C) | Confirm the existing thermostat and gasket arrangement. |
| MerCruiser | 8.2L | 160°F (71°C) | Confirm the existing thermostat and gasket arrangement. |
Technical Specifications
- Product Type
- Thermostat service kit
- Temperature Rating
- 160°F (71°C)
- Compatible Engine Displacements
- MerCruiser 4.3L, 5.0L, 5.7L, 7.4L, and 8.2L configurations
- Primary Replacement References
- 807252Q5 and 807252T8
- Additional Kit Reference
- Sierra 18-3647
- Installation
- Service replacement; follow the engine service manual for the correct procedure and tightening specifications
What's in the Box
- 1 x 160°F thermostat, reference 807252-2
- 1 x O-ring, reference 25-30224
- 1 x housing sleeve, reference 806922
- 1 x gasket, reference 27-33179-2
- 1 x gasket, reference 27-47510
- 1 x gasket, reference 27-48818-1
- 1 x housing gasket, reference 27-33918
Installation Notes
- Allow the engine to cool completely before beginning service and follow all applicable marine-engine safety procedures.
- Disconnect the battery if required by the engine service manual.
- Locate the thermostat housing and note the orientation of the existing thermostat, sleeve, and gaskets before removal.
- Remove the housing fasteners and carefully take out the old thermostat, sleeve, O-ring, and gaskets.
- Clean the mating surfaces thoroughly without allowing debris to enter the cooling passages.
- Install the supplied thermostat, housing sleeve, O-ring, and the gasket that matches the engine's housing arrangement.
- Reinstall the housing and tighten the fasteners according to the engine manufacturer's specified sequence and torque.
- Operate the engine according to the service manual and check for leaks and normal temperature regulation before returning the vessel to service.
Troubleshooting & FAQ
How do I confirm that this kit fits my engine?
Confirm that your MerCruiser engine is one of the listed 4.3L, 5.0L, 5.7L, 7.4L, or 8.2L configurations, then compare the existing thermostat or replacement reference with 807252Q5 or 807252T8. Also compare the housing and gasket arrangement with the components listed in this page.
What temperature is this thermostat?
This kit contains a 160°F (71°C) thermostat.
Why are several gaskets included?
The kit includes the gaskets specified for the listed service application, including gasket references 27-33179-2, 27-47510, 27-48818-1, and 27-33918. Use the gasket that matches the housing arrangement on your engine rather than installing every gasket in every application.
Does the kit include a thermostat housing?
No. The kit includes a housing sleeve and sealing components, but the thermostat housing itself is not listed as an included component.
What should I do if my existing parts look different?
Do not force an installation. Compare the existing thermostat, sleeve, O-ring, and gasket arrangement with the listed components and consult the engine service manual or a qualified marine technician before proceeding.
When should a marine thermostat be inspected?
Inspect the thermostat during scheduled cooling-system service and whenever the engine shows overheating, runs unusually cool, or has unstable temperature readings. Replace damaged or contaminated seals during service.
Safety & Important Information
- Verify the engine displacement, thermostat reference, housing arrangement, and gasket layout before ordering.
- Work only on a completely cool engine and follow the applicable service-manual procedures.
- Do not assume that every listed gasket is used simultaneously on every engine configuration.
- Professional installation is recommended when the correct thermostat arrangement or installation procedure is uncertain.
About Sea Sierra
- Marine Parts Support — We provide application-focused replacement parts for marine engine service.
- Fitment Guidance — Compare engine displacement, existing references, and component layout before ordering.
- Service-Ready Components — Kits are supplied with the listed thermostat and sealing components for the stated application.
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