MerCruiser Thermostat Seal – 8071341
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You have 30 days to request a return. All sale items are final sale.
he Mercury MerCruiser Thermostat Seal 8071341 is a genuine OEM rubber sealing ring designed to properly seal the thermostat within the thermostat housing on GM-based MerCruiser engines. This seal ensures correct coolant flow direction and prevents internal bypass leakage, which is critical for maintaining proper engine operating temperature.
Manufactured from marine-grade rubber, this seal is built to withstand continuous exposure to heat, coolant, and raw water environments without degrading or losing sealing integrity. It is a direct replacement component typically used during thermostat service or replacement.
Key Features
- Genuine Mercury MerCruiser / Quicksilver OEM seal
- Designed for thermostat-to-housing sealing
- Prevents coolant bypass and internal leakage
- Marine-grade rubber construction for durability
- Direct OEM fit — no modification required
- Critical component for proper cooling system operation
Engine Compatibility
Fits a wide range of GM-based MerCruiser engines:
- 4.3L V6
- 5.0L V8 (305)
- 5.7L V8 (350)
- 7.4L V8 (454)
- 8.2L V8 (502)
Applications include:
- MerCruiser Alpha and Bravo sterndrives
- MerCruiser inboard engines
- Used in both raw water and some closed cooling thermostat housings
✔ Commonly used with thermostat kits such as 807252T5 and 807252T4
✔ Installed between thermostat and housing bore
Serial Number Fitment Notice
Fitment can vary depending on thermostat housing design and engine serial number. Always confirm using your engine serial number or visually match your existing seal before ordering.
When This Part Needs Replacement
- During thermostat replacement or service
- Coolant leaks at thermostat housing
- Engine not maintaining proper temperature
- Seal appears flattened, cracked, or brittle
- Preventative maintenance during cooling system service
Installation Notes
- Lightly lubricate seal with clean coolant before installation
- Ensure seal is seated evenly in housing groove
- Do not reuse old seals — always replace when removed
- Inspect thermostat housing for corrosion or pitting
- Verify proper thermostat orientation before reassembly
Alternate / Superseded / Cross-Reference Part Numbers
- Mercury / Quicksilver: 8071341
- Sierra: 18-0396
- GLM: 13110
- Often included in thermostat kits (e.g., 807252T5, 807252T4)
Parts Desk Insight
This is a small but critical component. A worn or missing thermostat seal will cause improper coolant flow, often leading to engines running too cold or overheating inconsistently. It’s standard practice to replace this seal anytime the thermostat is serviced — reusing the old one is a common cause of repeat issues.
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.