Skip to content
☀️ Take an Additional 10% Off Your Entire Order with code PROGRADE10 at checkout.
☀️ Additional 10% Off • PROGRADE10
Flexfab 5521-100, 1" x 25 ft Green Premium Silicone Heater Hose, 1.00"

Flexfab 5521-100, 1" x 25 ft Green Premium Silicone Heater Hose, 1.00"

by Flexfab
Save 20% Save 20%
$ 335.19
$ 335.19 - $ 335.19
$ 335.19
$ 268.15
$ 268.15 - $ 268.15
$ 268.15
Request a Quote (Bulk & Dealer Orders)

Quick Specs

BrandFlexfab
Series5521
TypeHose
Body Size1"
Length25 ft
ColorGreen

Performance & Construction

Construction Green cover/red liner silicone, 1-ply nylon
Inside Diameter 1.00" (25 mm)
Outside Diameter 1.39" (35 mm)
Actual Burst Pressure 300 PSI
Working Pressure ~100 PSI (1/3 of burst)
Temperature Range -65F to +350F
Wall Thickness .170"/.220"
Standards SAE J20 R3 Class A; TMC RP303B Cl I Gr II
Origin Made in USA

Product Details

Product Details

The Flexfab 5521-100 is a green cover/red liner silicone, 1-ply nylon hose engineered for demanding engine environments. It resists hardening, cracking, cold leaks, aging, and many chemicals, making it a durable, long-lasting solution for diesel, automotive, marine, agricultural, and industrial cooling systems. The recommended Flexfab clamp for this size is shown in the chart below.

Why this hose

  • Green cover/red liner silicone, 1-ply nylon — durable construction engineered for demanding cooling-system service.
  • -65F to +350F range — stays flexible in cold and handles under-hood heat without hardening or cracking.
  • Resists hardening, cracking, cold leaks, aging, and many chemicals — long service life where ordinary rubber fails.
  • Meets SAE J20 R3 Class A; TMC RP303B Cl I Gr II — engineered to recognized heavy-duty hose standards.

Frequently asked questions

Is this hose fuel-rated?
No. Silicone heater hose is for coolant, radiator, and heater applications — it is not fuel-resistant. Do not use for fuel or oil lines.

What clamp does it take?
Use the Flexfab 2582‑0016 clamp, sized to this hose’s outside diameter. Two clamps per connection is standard practice.

Flexfab 5521 Series — Complete Size & Clamp Chart

Every size in the series. Click a part number to open that product. The clamp column shows the Flexfab clamp(s) that fit each hose OD.

Part ID
(in)		 ID
(mm)		 OD
(in)		 OD
(mm)		 Actual
Burst		 SAE TMC Weight
(lb/ft)		 Matching
Clamp
5521‑025X25
5521‑025X50
5521‑025X800 		0.25" 6 0.64" 16 475 PSI 475 125 0.121 2582‑0006
5521‑031X25
5521‑031X600 		0.31" 8 0.70" 18 475 PSI 475 125 0.151 2582‑0006
5521‑038X25
5521‑038X50
5521‑038X500 		0.38" 10 0.77" 20 475 PSI 475 125 0.181 2582‑0006
5521‑050X25
5521‑050X50
5521‑050X500 		0.50" 13 0.89" 23 425 PSI 425 125 0.226 2582‑0006
5521‑062X25
5521‑062X50
5521‑062X400 		0.63" 16 1.02" 26 375 PSI 375 125 0.258 2582‑0010
5521‑075X25
5521‑075X50
5521‑075X300 		0.75" 19 1.14" 29 325 PSI 325 125 0.301 2582‑0012
5521‑087X25
5521‑087X50
5521‑087X150 		0.88" 22 1.27" 32 300 PSI 300 125 0.346 2582‑0012
5521‑100X25
5521‑100X50
5521‑100X200 		1.00" 25 1.39" 35 300 PSI 300 125 0.391 2582‑0016
5521‑125X25
5521‑125X50
5521‑125X150 		1.25" 32 1.64" 42 200 PSI 275 125 0.491 2582‑0020

Pairs With

Flexfab 2582-0016 Lined Worm Gear Clamp, 0.75"–1.00" ID, 300 SS, 10 Per Box Flexfab 2582-0016 Lined Worm Gear Clamp The matching half for this connection. Most buyers need both. $ 19.99
FLEXFAB

Industrial silicone hose engineered for heater, coolant, and high temperature service. Genuine Flexfab product with correct part numbers and specifications.

Shop All Flexfab

Request a Quote

Bulk and dealer pricing. Tell us what you need and we’ll reply within one business day.