Quicksilver Extended Life Coolant/Antifreeze – Pre-Diluted 50/50, 1 Gallon
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Quicksilver Extended Life Coolant/Antifreeze – Pre-Diluted 50/50, 1 Gallon
Keep your MerCruiser closed cooling system protected year-round with Quicksilver Extended Life Coolant/Antifreeze. Formulated specifically for MerCruiser sterndrive and inboard gasoline engines with closed cooling systems, this coolant delivers 5-year or 1,000 operating hour extended life protection — far beyond what conventional antifreeze provides.
Pre-diluted to a ready-to-use 50/50 mix with de-ionized water, so there’s no measuring or mixing required. The ethylene glycol base provides freeze and boil-over protection, while the silicate- and phosphate-free formula protects aluminum and other metals in the cooling system without causing gelling or compatibility issues with conventional antifreeze.
Meets ASTM D-3306 and ASTM D-4340 requirements. Contains a 10 ppm bittering agent. See your engine’s owner’s manual or service manual for specific application instructions and capacity.
Key Features
- 5-year / 1,000 operating hour extended life protection
- Pre-diluted 50/50 with de-ionized water — ready to use
- Ethylene glycol base for freeze and boil-over protection
- Silicate and phosphate free — safe for aluminum cooling system components
- Will not cause gelling
- Compatible with conventional antifreeze
- Meets ASTM D-3306 and ASTM D-4340 requirements
- Contains 10 ppm bittering agent
- 1 gallon
Compatible Applications
- MerCruiser closed cooling systems
- MerCruiser sterndrive gasoline engine applications
- MerCruiser inboard gasoline engine applications
- Cooling system flush and refill service
- Winterization of closed cooling systems
Parts Desk Insights
This is the correct coolant for MerCruiser engines equipped with a closed (freshwater) cooling system — not raw water cooled engines, which don’t use antifreeze in the same way. The 5-year / 1,000-hour service interval is a genuine advantage over conventional antifreeze, which typically requires annual replacement. The pre-diluted 50/50 formula is the right concentration for most climates; if you’re in an extreme cold-weather environment, check your owner’s manual for guidance on whether a higher concentration is needed. The silicate-free formula is important for aluminum-heavy cooling systems — silicate-based coolants can cause deposits and corrosion in these engines over time. Always flush the old coolant completely before refilling, and confirm the total system capacity from your service manual so you order enough to do the job properly.
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.