Thermostat Housing Hose – Fits Volvo Penta & MerCruiser 2.5L 3.0L 4-Cylinder (Replaces 3857391, 32-96879)

Product Details

This Thermostat Housing Hose is designed for Volvo Penta and MerCruiser 2.5L and 3.0L 4-cylinder engines, providing a reliable connection between the thermostat housing and the circulating water pump. Built for models manufactured from 1982 through 2003, it ensures proper coolant flow and temperature regulation across compatible marine engines.

This aftermarket hose directly replaces OEM part numbers 3857391, 509282, 8M0071007, 9-44050, 96879, and manufacturer PN 32-96879, offering broad cross-compatibility with factory components.

• Precision-molded to match OEM fitment on MerCruiser 4-cylinder 2.5L and 3.0L engines
• Fits model years 1982–2003 for consistent compatibility across multiple engine generations
• Constructed to handle marine cooling system pressures and temperatures

Part Number Matrix

Use this matrix to confirm equivalent references across OEM and aftermarket.

Engine & Model Compatibility

Confirm your engine model/year in the table below.

Technical Specs

Part Type

Hose

Application

Thermostat Housing to Circulating Water Pump

Compatible Engine Types

MerCruiser 4-Cylinder 2.5L, 3.0L; Volvo Penta 4-Cylinder 2.5L, 3.0L

Model Year Range

1982–2003

Primary OEM Numbers

3857391, 32-96879

What's in the Box

• Thermostat Housing Hose (1 piece)

Installation Notes

1. Drain the cooling system and relieve any residual pressure before removing the old hose.
2. Disconnect clamps at both the thermostat housing and circulating water pump ends.
3. Remove the old hose and inspect mating surfaces for corrosion or damage.
4. Clean both connection points to ensure a secure seal.
5. Slide new hose onto fittings, ensuring full seating on both ends.
6. Install clamps and tighten to manufacturer-specified torque, avoiding over-compression.
7. Refill cooling system with appropriate marine-grade coolant mixture.
8. Start engine and check for leaks at both hose connections while monitoring temperature gauge.

Troubleshooting & FAQ

How do I confirm this hose fits my engine?

Cross-reference your engine's serial plate or existing hose part number with the compatibility table above. If your MerCruiser or Volvo Penta 2.5L or 3.0L 4-cylinder engine was built between 1982 and 2003, this hose is designed to fit.

What are signs this hose needs replacement?

Look for cracks, soft spots, bulging, or visible leaks at the connection points. Overheating or coolant loss without obvious leaks elsewhere may also indicate hose failure.

Can I reuse the old clamps?

Inspect clamps for corrosion, thread damage, or deformation. Replace if any wear is visible to ensure a proper seal and prevent future leaks.

Does this hose come pre-shaped for the engine?

Yes, this hose is molded to the correct angle and length for MerCruiser and Volvo Penta 4-cylinder thermostat housing installations, matching OEM routing.

What coolant should I use after installation?

Use marine-grade ethylene glycol coolant mixed per your engine manufacturer's recommendations, typically a 50/50 ratio with distilled water.

How tight should I clamp the hose?

Tighten clamps until snug but avoid excessive force that could cut into the hose material or distort the fitting. Follow torque specs if provided in your service manual.

OEM vs. Aftermarket?

This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.

Shipping speed & cost

We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.

Warranty & returns

Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.

Safety & Important Info

• Verify images/specifications against your original part. If anything differs—even if your model appears compatible—do not purchase.
• This is an aftermarket replacement, not an OEM component.
• Professional installation is recommended for safety and performance.

About Sea Sierra

• Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
• Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
• Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.