Sierra 18-3601
Sierra 18-3601 — Product description
Keep your boat's engine running cool and reliable with the Sierra 18-3601 water inlet hose. Designed as a direct replacement for MerCruiser engines, this durable 5/8-inch inner diameter by 14-inch long hose ensures proper water flow to your cooling system, preventing overheating during those long days on the water. Marine enthusiasts trust Sierra parts for their precision engineering and long-lasting performance, making this hose a smart upgrade or replacement for worn-out originals.
Key Features of the Sierra 18-3601 Water Inlet Hose
- Exact Fit Specifications: Measures 5/8" ID x 14" long, matching OEM standards for seamless installation on compatible MerCruiser models.
- High-Quality Construction: Made from reinforced rubber that resists cracking, swelling, and deterioration from constant exposure to saltwater, fuel, and engine heat.
- Meets or Exceeds Standards: ABYC and NMMA certified, ensuring safety and reliability in demanding marine environments.
- Easy Maintenance: Smooth inner lining promotes unrestricted water flow, reducing the risk of clogs and maintaining optimal engine temperatures.
- Cost-Effective Reliability: Sierra's aftermarket expertise delivers OEM-level performance at a fraction of the cost, without compromising quality.
Perfect Compatibility for MerCruiser Engines
This hose fits a wide range of MerCruiser stern drive and inboard engines, including popular models from the 1980s through the 2000s. It's commonly used in the raw water cooling system, connecting the water pickup to the engine's heat exchanger or pump. Always cross-reference with your engine serial number for the best match—Sierra parts are engineered to restore factory performance, whether you're rebuilding an Alpha One, Bravo, or Big Block setup.
Simple Installation Tips for Optimal Performance
- Drain the cooling system and remove the old hose by loosening clamps and gently twisting it free.
- Clean mating surfaces on the fittings to ensure a secure seal.
- Route the new Sierra 18-3601 hose following the original path to avoid kinks or sharp bends.
- Secure with stainless steel hose clamps (not included) torqued to manufacturer specs—typically 20-30 in-lbs.
- Refill the system, check for leaks, and test run the engine at idle to verify flow.
Pro tip: Inspect adjacent hoses and fittings during replacement to catch potential issues early, extending the life of your entire cooling system.
Why This Hose Boosts Engine Longevity and Maintenance Tips
A failing water inlet hose can lead to overheating, warped heads, or seized pistons—costly repairs no boater wants. The Sierra 18-3601 prevents these headaches by delivering consistent water intake, even under high RPMs. Pair it with routine checks: flush your cooling system after every saltwater outing, inspect for soft spots or bulges annually, and replace every 3-5 years based on usage. Boat owners report fewer breakdowns and smoother performance after swapping to Sierra hoses.
Real-World Advantages
- Handles extreme temperatures from -40°F to 250°F without failure.
- Reduces engine noise from water pump cavitation.
- Improves fuel efficiency by maintaining ideal operating temps.
Frequently Asked Questions
SKU: NVN-4004058
MPN: 18-3601
UPC: 808282258801
Technical specifications
| Brand | Sierra Engine Parts |
| Model | Sierra 18-3601 |
| SKU / MFR# | 4004058 |
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Frequently asked questions
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