Flexfab 5515-138, 1.38" x 3 ft, 3-Ply Blue Silicone Coolant Hose, 35mm

A versatile heavy-duty coolant hose for diesel, automotive, marine, agricultural, and industrial cooling systems, the Flexfab 5515-138 is a 3-ply blue silicone hose built to resist hardening, cracking, cold leaks, and aging where ordinary rubber fails.

Why this Flexfab 3-ply coolant hose

• 3-ply polyester reinforcement — 400 PSI actual burst, a wide margin over the ~133 PSI working pressure of most cooling systems.
• −65°F to +350°F range — stays flexible in cold and handles under-hood heat without going brittle.
• Meets SAE J20 R1 Class A & TMC RP303B Class I Grade II — documented spec-grade performance.
• 1.38" (35mm) ID × 1.7" (43mm) OD — precise sizing for a clean clamp seal.
• Resists oil splash, ozone, and direct sunlight — long service life in hostile engine environments.

Cut to a 3-foot stick, ready to install, and pairs with a Flexfab 2582-0020 clamp for a leak-free connection.

Backed by hpcouplers’ fast shipping and easy returns.

• FlexFab Series: 5515
• Part Number: 5515-138
• Inside Diameter (ID): 1.38" (35mm)
• Outside Diameter (OD): 1.7" (43mm)
• Hose Length: 3 feet
• Wall Thickness: .140" / .190"
• Weight LB/FT: 0.44
• Actual Burst Pressure - PSI: 400
• SAE J20 R1 Class A - PSI: 250 PSI
• TMC RP303B Class I Grade II - PSI: 125 PSI
• Extreme temp range: -65F to +350F
• Construction: Blue Silicone hose with 3-ply of Polyester reinforcement