Sierra Molded Hose 18-70934, Replaces Mercury Marine 32-89718-1, Fits MCM/MIE GM V-8 427 454 502 Engines

The Sierra 18-70934 is a molded rubber cooling hose built for MerCruiser I/O cooling systems. It is engineered as a direct equivalent to Mercury Marine part 32-89718-1, giving boat owners a reliable option when the factory hose on their MCM/MIE GM V-8 (427, 454 & 502 cid) engine needs replacement. The hose measures 14 inches in length with a 1 3/4 inch inside diameter and a 1.75 inch outside diameter, and is molded in white to match factory cooling system components.

Construction is polyethylene (PE), a material chosen for resistance to the heat, vibration, and constant flow conditions found in a marine cooling circuit. The molded shape is designed to route cleanly through the engine bay without kinking, maintaining consistent coolant or raw water flow to the engine. This is a universal-fit hose for the specified GM V-8 MerCruiser applications, making it a straightforward swap for a cracked, hardened, or leaking original hose.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-70934
• Material: Polyethylene (PE)
• Color: White
• Inside Diameter: 1 3/4 inches
• Outside Diameter: 1.75 inches
• Length: 14 inches
• Weight: 1.35 pounds
• Fit Type: Universal Fit
• Application: I/O Mercruiser Cooling System
• OEM Cross Reference: 32-89718-1
• UPC: 808282203344

Fitment

• MCM/MIE GM V-8 (427, 454 & 502 cid) engines

Replaces (OEM)

• Mercury Marine 32-89718-1

Frequently Asked Questions

What engines does the Sierra 18-70934 hose fit? The Sierra 18-70934 molded hose fits MCM/MIE GM V-8 engines in 427, 454, and 502 cid displacements.

Is the 18-70934 hose a genuine OEM part or an aftermarket replacement? It is an aftermarket Sierra part manufactured as a direct equivalent to Mercury Marine 32-89718-1, not a Mercury-branded original.

What is the inside diameter of this hose? The Sierra 18-70934 has a 1 3/4 inch inside diameter.

How long is the Sierra 18-70934 molded hose? This hose measures 14 inches in length.

What is the outside diameter of the 18-70934 hose? The outside diameter is 1.75 inches.

What material is the 18-70934 cooling hose made from? It is molded from polyethylene (PE), chosen for its resistance to heat and vibration in a marine cooling system.

What color is the Sierra 18-70934 hose? The hose is white, matching the factory-molded cooling hoses used on these MerCruiser applications.

Does part number 32-89718-1 cross-reference to the Sierra 18-70934? Yes, Sierra 18-70934 replaces Mercury Marine part 32-89718-1.

How much does the Sierra 18-70934 hose weigh? It weighs 1.35 pounds.

Will the 18-70934 hose fit both port and starboard sides? The 18-70934 is a universal-fit hose for MCM/MIE GM V-8 427, 454, and 502 cid engines, with no side-specific designation given.

What signs indicate the original cooling hose needs replacement with a part like the 18-70934? Cracking, hardening, or leaking at the hose connections are common reasons to replace a MerCruiser cooling hose such as the Sierra 18-70934.