Motorcraft heater hoses are Ford OEM service parts — same part Ford dealers install. They are pre-formed to the factory routed length and shape for your specific application, so no trimming, splicing, or adapter fittings are needed.

KH-536 is a branched (tee) hose with a Branch Quantity of 2, meaning it has two outlet ends plus the inlet — three connection points total. KH-337 is a straight or single-bend hose with one inlet and one outlet. Check your vehicle's routing diagram before ordering to confirm which configuration your system uses.

EPDM (Ethylene Propylene Diene Monomer) is the same elastomer Ford specifies for factory heater hoses. It resists coolant chemistry, ozone, and heat better than older neoprene or plain rubber hoses, and it maintains flexibility at low temperatures. If your original hose is cracking or feels spongy, the Motorcraft EPDM replacement is the exact-spec upgrade.

Both KH-337 and KH-536 are rated to 304.58 psi working pressure. A typical Ford pressurized cooling system runs 13–16 psi at the radiator cap, so these hoses are rated to more than 18× normal operating pressure — well within safe margin for a factory heater circuit.