Sierra Molded Coolant Hose 18-70940, Thermostat Housing to Port Exhaust Manifold, Replaces 32-860144

The Sierra 18-70940 is a molded coolant hose engineered to route coolant from the thermostat housing to the port exhaust manifold on a range of MerCruiser stern drive engines. Built as a direct-fit replacement for Mercury Marine part 32-860144, it is molded to the OEM bend radius and connection geometry so it seats correctly at both the thermostat housing and the port exhaust manifold without kinking or requiring modification.

This hose is designed for engines including the 262 Mag with Fuel Cool, 4.3L-LX (1996 and up) with a one-piece manifold, 5.0L-EFI (1998 and up), 350 Mag-MPI (1997-2001), 5.7L-EFI (1996-97), and 6.2L MPI (2001 and up), as well as MCM V-6 and V-8 (305, 350, and 377 cid) engines. Because it is molded specifically for the port-side exhaust manifold routing, it is not interchangeable with a starboard-side hose; a separate Sierra part number covers the corresponding starboard application.

Replacing a cracked, softened, or leaking coolant hose in this circuit helps prevent coolant loss and overheating, and installing the correct molded shape (rather than a straight or flexible substitute) avoids stress on the hose barbs at the thermostat housing and manifold. Weighing 0.74 pounds, this hose ships ready to install with standard hose clamps.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-70940
• Product Type: Molded Coolant Hose
• Application: Thermostat housing to port exhaust manifold
• Weight: 0.74 pounds
• OEM Cross Reference: 32-860144
• UPC: 808282227692

Fitment

• 262 Mag with Fuel Cool
• 4.3L-LX (1996 and up) with 1 pc. Manifold
• 5.0L-EFI (1998 and up)
• 350 Mag-MPI (1997-2001)
• 5.7L-EFI (1996-97)
• 6.2L MPI (2001 and up)
• MCM V-6 & V-8 (305, 350 & 377 cid) engines

Replaces (OEM)

• 32-860144

Frequently Asked Questions

What does the Sierra 18-70940 hose connect? The Sierra 18-70940 is a molded coolant hose that runs from the thermostat housing to the port exhaust manifold on applicable MerCruiser engines.

Is the 18-70940 hose for the port or starboard side? It is designed specifically for the port exhaust manifold routing. It is not interchangeable with the starboard side, which uses a different Sierra part number.

What OEM part number does this hose replace? It replaces Mercury Marine part number 32-860144.

Which engines does the 18-70940 hose fit? It fits the 262 Mag with Fuel Cool, 4.3L-LX (1996 and up) with a one-piece manifold, 5.0L-EFI (1998 and up), 350 Mag-MPI (1997-2001), 5.7L-EFI (1996-97), 6.2L MPI (2001 and up), and MCM V-6 & V-8 (305, 350 & 377 cid) engines.

How much does the 18-70940 hose weigh? 0.74 pounds.

Will this hose fit a 350 Mag-MPI engine? Yes, the 18-70940 is listed for 350 Mag-MPI engines from 1997 to 2001.

Does the 18-70940 work on a 5.7L-EFI engine? Yes, it is designed for 5.7L-EFI engines from 1996-97.

What is the difference between the 18-70940 and the 18-70943 hose? The 18-70940 covers the 262 Mag, 4.3L-LX, 5.0L-EFI, 350 Mag-MPI, 5.7L-EFI, and 6.2L MPI engines and replaces 32-860144, while the 18-70943 covers larger 7.4L, 454 Mag, and 502 Mag engines and replaces 32-897491. Both route the thermostat housing to the port exhaust manifold but fit different engine displacements.

Is this hose genuine Sierra or aftermarket? The 18-70940 is a Sierra part number, sold as a molded replacement hose engineered to the same fit as the original Mercury Marine 32-860144 hose.

Can I use the 18-70940 on a 4.3L engine? Yes, it fits the 4.3L-LX (1996 and up) with a one-piece manifold.

Does the 18-70940 fit 6.2L MPI engines? Yes, it is listed for 6.2L MPI engines from 2001 and up.