Engine cooling systems and fuel lines run under pressure. Without a secure connection, hot coolant or fuel would easily blow the flexible rubber hoses off their fittings. A hose clamp wraps around the end of the hose, squeezing the rubber tightly against the metal pipe barb. This creates a leak-proof seal that can withstand high temperatures and pressures.
Hose clamps come in several styles. The worm-gear clamp uses a screw to tighten a slotted metal band. Constant-tension spring clamps are made of spring steel that expands and contracts with engine heat. When installing worm-gear clamps, do not over-tighten them. Squeezing too hard can cut into the soft rubber of the hose, causing it to split and leak over time.