Flexfab 5526-031x50, 5/16" ID x 50 ft Box Blue Silicone Heater Hose, 8mm 350F Radiator Coolant

Upgrade your heater and coolant lines with the Flexfab 5526-031x50 standard silicone heater hose — a 50-foot box of 5/16" ID hose engineered for superior flexibility and long life. Unlike ordinary rubber heater hose, silicone resists hardening, cracking, cold leaks, and coolant-additive attack, so it keeps sealing season after season.

Why this Flexfab silicone heater hose

• Silicone with 1-ply nylon reinforcement — superior flexibility with a 310 PSI burst rating, which means easy routing and a wide margin over the ~103 PSI working pressure of heater circuits.
• −65°F to +350°F range — handles under-hood heat and winter cold without going brittle or soft.
• Meets SAE J20 R3 Class A & TMC RP303B Class I Grade II — documented heater-hose spec performance.
• Resists coolant additives, ozone, and aging — extreme-duty-cycle tested for hostile engine environments.
• 5/16" (8mm) ID × 0.64" (16mm) OD, bend radius 5× ID — tight, kink-free routing.

Supplied as a continuous 50-foot box, ideal for heater core, radiator, and coolant-system runs. Pairs with a Flexfab 2582-0006 clamp for a secure seal. (Silicone heater hose is for coolant/heater use — not fuel.)

Backed by hpcouplers’ fast shipping and easy returns — order with confidence from a trusted industrial hose and coupler supplier.

• FlexFab Series: 5526
• Part Number: 5526-031x50
• Inside Diameter (ID): 0.31" (8mm)
• Outside Diameter (OD): 0.64" (16mm)
• Overall Length: 50 feet (Box)
• Wall Thickness: .140" / .170"
• Weight LB/FT: 0.128
• Actual Burst Pressure - PSI: 310
• SAE J20 R3 Class A - PSI: 250
• TMC RP303B Class I Grade II - PSI: 125
• Bend Radius: 5x ID
• Extreme temp range: -65F to +350F
• Construction: Blue Silicone hose with 1-ply nylon fiber reinforcement