Silicone Hose vs Rubber Hose in Turbo and Cooling Systems
A turbocharger outlet can push charge-air temperatures past 200 °C, and under-bonnet soak temperatures regularly exceed 120 °C after shutdown. Standard EPDM coolant hose begins to harden and crack in that environment, which is why silicone has become the default for performance and heavy-duty applications.
Where silicone hose wins
- Temperature: -60 °C to +220 °C continuous, versus about 125 °C for EPDM.
- Service life: silicone does not age-harden, so burst-prone cracking is far less common.
- Flexibility in tight routing: multi-ply hand-built hoses bend to tight radii without collapsing.
- Appearance: stable colours and a clean finish matter for show cars and branded engine bays.
Where rubber hose is still the right answer
- Oil and fuel contact: silicone swells in hydrocarbons — use NBR or FKM lined hose inside the crankcase area.
- Abrasion: silicone covers scuff more easily than EPDM; add a protective sleeve in rubbing areas.
- Cost: for a low-temperature coolant line with easy access, EPDM is cheaper and perfectly adequate.
Specifying a silicone hose
- Plies: 3-ply for vacuum/low pressure, 4 – 5 ply for turbo pressure above 1 bar.
- Reinforcement: polyester for standard duty, Nomex (aramid) for high temperature and high pressure.
- Liner: Fluorosilicone liner if the hose carries oil mist.
- Shape: straight, 45°, 90°, 135°, 180°, reducer, hump or T-piece; specify leg lengths.
- Clamps: use constant-tension or lined worm-drive clamps; overtightening a standard clamp cuts the cover.
FAQ
Can I use silicone hose for fuel or oil? No — use NBR, FKM or a fluorosilicone-lined hose. Standard silicone degrades with hydrocarbon contact.
Do silicone hoses need special clamps? A smooth-bore clamp with rolled edges, tightened to the recommended torque, is enough in most cases. Avoid sharp-edged cheap clamps on 3-ply hose.
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