Sierra 18-3219
Sierra 18-3219 — Product description
Enhance Cooling Efficiency with the Sierra 18-3219 Water Tube
In the demanding world of marine engines, maintaining optimal coolant flow is non-negotiable. The Sierra 18-3219 water tube steps in as a reliable upgrade, serving as a direct replacement for the Mercury Quicksilver 710-42724A3. Crafted to mirror OEM specifications, this component ensures seamless water circulation through your MerCruiser engine's manifold and riser system, warding off overheating and extending engine life during long outings on the water.
Whether you're tackling rough seas or leisurely cruises, this water tube delivers consistent performance. Its design tackles common issues like blockages or cracks that plague aging hoses, keeping your V8 powerplant running cool under pressure. Boaters swear by it for restoring factory-level cooling without the hassle of custom fittings.
Seamless Compatibility for Popular MerCruiser Models
The Sierra 18-3219 fits a range of GM-based MerCruiser engines, including 4.3L, 5.0L, 5.7L, and 7.4L V8 configurations found in sterndrive and inboard setups. It's engineered for manifolds like the 0C385xxx or 0D24xxxx series, making it a go-to for owners of Alpha One, Bravo, and similar drives.
- Direct OEM interchange with 710-42724A3
- Ideal for freshwater and saltwater environments
- Matches lengths and bends for plug-and-play installation
Before swapping, double-check your manifold stampings to confirm fit—most listings align perfectly with mid-1980s to early 2000s models, but variations exist based on serial numbers.
Superior Features That Stand Out
What sets the Sierra 18-3219 apart? It's built from durable, reinforced rubber compounds resistant to heat, ozone, and electrolysis—key culprits in marine corrosion. The precise inner diameter promotes unrestricted flow, reducing backpressure that can strain your water pump.
- Exact OEM dimensions: 3/4-inch ID with pre-formed shape for manifolds
- High-temperature tolerance: Handles up to 250°F without softening
- UV and chemical resistant: Built for bilge exposure and fuel spills
- Lightweight yet robust: Easier handling during DIY repairs
Unlike generic hoses, this tube's molded ends ensure leak-free connections to barbs, minimizing drips that lead to dry-running impellers.
Step-by-Step Installation Guide
Replacing your water tube is a straightforward weekend project that saves trips to the shop. Tools needed: pliers, hose cutters, marine sealant, and rags.
- Shut off the engine, relieve cooling system pressure, and drain the manifold.
- Loosen clamps on the old tube at the manifold outlet and riser inlet.
- Gently twist and pull the tube free, noting routing to avoid kinks.
- Inspect barbs for corrosion; clean or replace if pitted.
- Apply marine grease to new tube ends, route carefully, and secure with stainless clamps.
- Refill coolant, start engine, and check for leaks at idle.
Pro tip: Run the engine on a hose for 10 minutes post-install to flush air pockets and verify flow.
Long-Term Benefits and Maintenance Insights
Investing in the Sierra 18-3219 isn't just about replacement—it's proactive protection. Proper circulation slashes risks of warped heads or seized pistons from localized hot spots. Pair it with annual impeller checks and zinc anode replacements for a bulletproof cooling loop.
Signs it's time for a new tube: milky exhaust, steam from the transom, or sluggish warm-up. Early detection keeps small fixes from snowballing into engine rebuilds. Saltwater boaters, flush religiously after use to double its lifespan.
Why Sierra Engine Parts Lead the Aftermarket
Sierra's reputation stems from rigorous testing against OEM benchmarks, often exceeding them in endurance trials. As a trusted name in marine aftermarket, they prioritize affordability without skimping on quality—think U.S.-sourced materials and ISO-certified production. Boaters choose Sierra for peace of mind, knowing it's backed by mechanics who've seen it outperform bargain brands in real-world abuse.
What engines is the Sierra 18-3219 water tube compatible with?
It's a direct fit for select MerCruiser GM V6 and V8 engines with manifolds using the 710-42724A3 OEM part, common in 4.3L to 7.4L models.
How do I know if my water tube needs replacing?
Look for cracks, softness, swelling, or restricted flow causing overheating. Annual inspections during winterization catch issues early.
Can I use this tube in saltwater applications?
Yes, its corrosion-resistant materials handle saltwater well, but regular flushing with fresh water extends its service life.
Does the Sierra 18-3219 require special tools for installation?
No, standard pliers and screwdrivers suffice. Use stainless clamps for longevity in wet environments.
What makes this better than universal hoses?
Pre-molded shape and exact sizing prevent kinks and leaks, matching OEM performance for reliable cooling.
How often should I replace the water tube?
Every 2-3 years or at signs of wear, especially in high-use or harsh conditions.
Will this fix exhaust manifold overheating?
Often yes, by restoring proper coolant routing, but check thermostat and pump too for complete diagnosis.
SKU: NVN-4003857
MPN: 18-3219
UPC: 808282243852
Technical specifications
| Brand | Sierra Engine Parts |
| Model | Sierra 18-3219 |
| SKU / MFR# | 4003857 |
Set product metafields under specs.* to populate this table.
Frequently asked questions
No questions yet. Got one? Drop us a line.
