MerCruiser Thermostat 160°F – 76270T (3.7L 470 / 485)
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You have 30 days to request a return. All sale items are final sale.
The Mercury MerCruiser Thermostat 76270T is a genuine OEM 160°F thermostat designed primarily for early MerCruiser 3.7L (470/485) inline 4-cylinder engines. This thermostat regulates engine temperature by controlling coolant flow, ensuring proper warm-up, stable operating temperature, and prevention of overheating.
This is a direct replacement for the original thermostat (76270), updated to the current “T” suffix version. It is specifically calibrated for raw water cooling systems commonly used on these engines, maintaining correct thermal balance for efficient combustion and engine longevity.
Key Features
- Genuine Mercury MerCruiser / Quicksilver OEM thermostat
- 160°F temperature rating (standard for raw water cooling)
- Direct replacement for part number 76270 (superseded)
- Designed for consistent engine temperature regulation
- Corrosion-resistant construction for marine environments
- Thermostat only (no gaskets or seals included)
Engine Compatibility
Primarily used on:
- MerCruiser 3.7L (470 / 485) inline 4-cylinder engines
- Model years approximately 1976–1982
Applications include:
- MerCruiser sterndrive (early Alpha systems)
- MerCruiser inboard variants using the 3.7L platform
✔ Designed for raw water cooled systems
✔ Not interchangeable with later GM V6/V8 thermostat kits
Serial Number Fitment Notice
Fitment is highly specific on 3.7L engines. Always confirm using your engine serial number or original part number before ordering. These engines have unique cooling system layouts compared to GM-based MerCruiser engines.
When This Part Needs Replacement
- Engine running too cold or overheating
- Slow warm-up or inconsistent temperature
- Thermostat stuck open or closed
- Corrosion or scaling found during inspection
- Cooling system service on older 3.7L engines
Installation Notes
- Replace gasket and seal (sold separately) during installation
- Install with spring side facing engine block
- Clean housing thoroughly before reinstalling
- Inspect water passages for corrosion (common on 3.7L engines)
- Verify proper circulation after startup
Alternate / Superseded / Cross-Reference Part Numbers
- Mercury / Quicksilver: 76270T
- Supersedes: 76270
- Sierra: 18-3552 (kit equivalent)
- Aftermarket references may include: 27-896561, 99155A1 equivalents
Parts Desk Insight
This thermostat is specific to the MerCruiser 470/485 platform, which uses a unique cooling system compared to standard GM-based engines. These engines are known for corrosion issues in cooling passages — if you’re replacing the thermostat, it’s a good time to inspect the entire system. Also note this is not interchangeable with 807252-series thermostat kits used on V6/V8 engines.
Shipping
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.