Sierra Molded Hose 18-70956 - Oil Cooler to Thermostat Housing, Replaces 32-16012, Fits MerCruiser 4.3L & MC175/205

The Sierra 18-70956 is a molded EPDM hose built to route coolant from the oil cooler to the thermostat housing on applicable MerCruiser stern drive engines. It is engineered for thermostat housings that have all four hose connectors cast directly into the housing, with no separate "T" connector - two hoses run to the manifold and two hoses run to the elbow. The hose is molded rather than cut-to-fit, so it holds its shape through bends without kinking and installs in the original factory routing without modification.

Construction is EPDM tubing with a synthetic knit reinforcement layer, giving the hose resistance to heat, oil exposure, and the flexing that comes with engine vibration in a marine environment. It is finished in white and manufactured to OEM quality so fit, form, and function match the original equipment. This hose is intended for MerCruiser MC175/205, 4.3L, 4.3L (Gen II), and 4.3LX (Gen II) applications using the four-connector thermostat housing design, and it directly replaces OEM/Quicksilver part 32-16012.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-70956
• Product Type: Molded Hose
• Replaces: 32-16012
• Fits: MC175/205 (1987), 4.3L (1988-92), 4.3L (Gen II) (1992-95), 4.3LX (Gen II) (1992-95)
• Application: Oil cooler to thermostat housing, four hose connectors cast into the thermostat housing (no "T" connector), two hoses to manifold and two hoses to elbow
• Material: EPDM with synthetic knit reinforcement
• Color: White
• Nominal Wall Thickness: 1/8 inch
• Weight: 0.93 pounds
• UPC: 808282265700

Fitment

• MerCruiser MC175/205 (1987)
• MerCruiser 4.3L (1988-92)
• MerCruiser 4.3L (Gen II) (1992-95)
• MerCruiser 4.3LX (Gen II) (1992-95)

Replaces (OEM)

• 32-16012

Frequently Asked Questions

What engines does the Sierra 18-70956 hose fit? The Sierra 18-70956 molded hose fits MerCruiser MC175/205 (1987), 4.3L (1988-92), 4.3L (Gen II) (1992-95), and 4.3LX (Gen II) (1992-95) engines that use a thermostat housing with all four hose connectors cast directly into it.

Does 18-70956 replace an OEM part number? Yes, it directly replaces OEM/Quicksilver part number 32-16012.

What is this hose used for? It routes coolant from the oil cooler to the thermostat housing, with two of its hose runs going to the manifold and two going to the elbow.

What material is the 18-70956 hose made from? It is molded from EPDM tubing with a synthetic knit reinforcement layer, chosen for heat and oil resistance in a marine cooling system.

What color is the hose? The Sierra 18-70956 molded hose is white.

How much does the 18-70956 hose weigh? It weighs 0.93 pounds.

Will this hose work with a thermostat housing that has a separate "T" connector? No. The 18-70956 is designed specifically for thermostat housings with all four hose connectors cast into the housing and no separate "T" connector.

How many hose connections are needed to install this part? Installation uses four connections total: two hoses run to the manifold and two hoses run to the elbow.

Is the 18-70956 hose genuine Sierra or a generic aftermarket part? It is a genuine Sierra part manufactured to OEM quality, so fit, form, and function match the original equipment it replaces.

What is the wall thickness of the 18-70956 hose? The nominal wall thickness is 1/8 inch.

What is the difference between the 18-70956 and 18-70955 hoses? The 18-70956 is built for MerCruiser MC175/205, 4.3L, and 4.3LX (Gen II) engines, while the related 18-70955 hose is designed for MC200/230, 5.0L Alpha, MC260, 350 Mag Alpha, 5.7L Alpha & Bravo, 454 Mag Bravo, and 7.4L (GenV) Bravo engines. Both share the same four-connector, no-"T"-connector design but are not interchangeable between engine families, so it is important to order the SKU matching your engine.