Flex Technologies HH-038-25 Silicone Heater Hose – 3/8" ID x 25 Foot Roll

The Flex Technologies HH-038-25 is a premium blue silicone heater hose designed for coolant, heating, and air line applications in heavy-duty trucks, marine, industrial, and automotive systems. This 3/8" inside diameter hose comes in a convenient 25-foot roll, allowing you to cut custom lengths as needed for your specific application. Reinforced with nylon fiber for added strength, this SAE J20 R3 Class A compliant hose resists hardening, cracking, cold leaks, and aging—delivering reliable performance in the harshest engine environments where rubber hoses fail prematurely.

Signs You Need New Heater Hose

• Visible cracks, splits, or dry rot on hose exterior
• Soft, spongy, or swollen sections indicating internal breakdown
• Coolant leaks at heater core or engine connections
• Low coolant level with no visible external leaks
• Sweet coolant smell inside cab or under hood
• Heater not producing adequate heat
• Collapsed or kinked hose restricting coolant flow
• Hose hardened and brittle from age or heat exposure

Specifications

Features

• Premium silicone construction outlasts standard rubber hoses
• Nylon fiber reinforcement for strength and pressure resistance
• Resists hardening, cracking, cold leaks, and chemical degradation
• Ozone and UV resistant for extended service life
• Meets or exceeds SAE J20 R3 Class A requirements
• Extreme temperature range handles cold starts to full operating temps
• Flexible design allows easy routing in tight spaces
• Cut-to-length convenience from 25-foot bulk roll

Applications

This 3/8" silicone heater hose is ideal for heater core connections, bypass lines, and small coolant lines on:

• Heavy-duty trucks (Freightliner, Kenworth, Peterbilt, International, Volvo, Mack)
• Medium-duty commercial vehicles
• Marine engines and watercraft
• Industrial and agricultural equipment
• Construction and mining machinery
• Automotive and performance applications
• Generator and power equipment cooling systems

Additional Sizes Available

• HH-025-25 – 1/4" ID x 25 ft
• HH-050-25 – 1/2" ID x 25 ft
• HH-062-25 – 5/8" ID x 25 ft
• HH-075-25 – 3/4" ID x 25 ft
• HH-100-25 – 1" ID x 25 ft
• HH-112-25 – 1-1/8" ID x 25 ft

Installation Tips: Cut hose clean and square using a sharp blade. Use clamps rated for silicone hose (constant tension or T-bolt style recommended). Ensure fittings and barbs are compatible with 3/8" ID hose. Do not over-tighten clamps as this can damage silicone material.

Measure your existing hose inside diameter before ordering to ensure proper fitment. This hose is sold by the roll—for per-foot pricing, please contact us.