Designed for heavy-duty cooling system service, the Silicone Rubber Blue Coolant Hose, 5.39 Inch OD, 5.00 Inch ID, 36 Inch Long is a Flexfab 4-ply silicone hose reinforced with polyester fabric and coated with a specially compounded silicone elastomer. The construction is rated to a burst pressure of 125 PSI and supports a continuous operating temperature range of -65°F to 350°F.
At 36 inches in length with a 5.00-inch inner diameter, this hose meets or exceeds SAE J20 R1 Class A, TMC RP303B Class 1 Grade 1, and the coolant hose specifications of most major OEM truck manufacturers, making it well suited for commercial and industrial vehicle cooling applications.
SKU: FLX5581-500
Supplier Part Number (MPN): 5581-500
Alternate Part Numbers: C1KH16
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Specifications
Burst Pressure
125
Brand
Flexfab
Brand
Flexfab
Pack Size
36.00
UOM
LN3
Hose I.D.
5
Hose O.D.
5.39
Length
36
Supplier Part Number
5581-500
Alternate Part Numbers
Alternate Part Number5581-500, Alternate Part Number C1KH16
Product Weight
7.56 lbs
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Product Questions & Answers (1)
Question by: Jean R on Nov 22, 2025, 7:11 PM
Got a truck that needs a 5-inch coolant hose and the original keeps failing in hot weather. What's the temp range on this one, and is it actually rated for continuous use or just short bursts?
Answer by: Customer Support on Nov 24, 2025, 12:45 PM
Continuous service is exactly what this hose is built for. The operating range runs from -65°F up to 350°F, and that's a sustained rating, not a peak or intermittent figure. For a truck running hard in high-heat conditions, that ceiling gives you a solid margin above what most cooling systems will ever throw at it. The 4-ply silicone construction with polyester reinforcement also helps it hold up over time rather than softening or cracking the way some rubber hoses do after repeated heat cycles.