Sierra 18-3058 Water Pump Impeller, Replaces OMC 983895, for OMC Sterndrive/Cobra 2.3L 2.5L 3.0L 4.3L

The Sierra 18-3058 is a water pump impeller engineered as a direct replacement for OMC 983895 on OMC Sterndrive/Cobra sterndrive cooling systems. The impeller is a core wear component of the raw water circulating pump, drawing cooling water through the engine to keep operating temperatures in check; over time the vanes lose flexibility and sealing ability, making periodic replacement necessary to prevent overheating and related engine damage. This part carries a machined finish and is supplied as a single impeller, ready to install into the existing water pump housing during routine maintenance or a full water pump rebuild.

Fitment covers OMC Sterndrive/Cobra cooling systems across the 2.3L (1987-1990), 2.5L (1986), 3.0L (1986-1992), and 4.3L (1986-1992) engine lines. Note that on the 2.3L and 3.0L applications, this impeller does not fit models originally equipped with a short impeller or those retrofitted with a short impeller kit. Always confirm your engine's original impeller configuration before ordering to ensure the 18-3058 is the correct replacement for your pump.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-3058
• Product Type: Impeller
• Replaces (OEM): 983895
• Finish: Machined
• Weight: 0.14 pounds
• Included Components: Impeller
• Quantity: 1
• UPC: 030999315144
• Fitment: OMC Sterndrive/Cobra Cooling System - 2.3L (1987-1990), 2.5L (1986), 3.0L (1986-1992), 4.3L (1986-1992)

Fitment

• OMC Sterndrive/Cobra 2.3L, 1987-1990 (except models originally equipped with short impeller or retrofitted with short impeller kit)
• OMC Sterndrive/Cobra 2.5L, 1986
• OMC Sterndrive/Cobra 3.0L, 1986-1992 (except models originally equipped with short impeller or retrofitted with short impeller kit)
• OMC Sterndrive/Cobra 4.3L, 1986-1992

Replaces (OEM)

• 983895

Frequently Asked Questions

What does the Sierra 18-3058 impeller replace? It replaces OMC 983895 and is designed to install as a direct equivalent in the OMC Sterndrive/Cobra raw water pump.

Which engines does the 18-3058 impeller fit? This impeller fits OMC Sterndrive/Cobra cooling systems on the 2.3L (1987-1990), 2.5L (1986), 3.0L (1986-1992), and 4.3L (1986-1992) engines.

Will the 18-3058 fit a 2.3L or 3.0L engine with a short impeller kit installed? No. On 2.3L and 3.0L OMC Sterndrive/Cobra engines, the 18-3058 does not fit models originally equipped with a short impeller or those retrofitted with a short impeller kit.

How much does the 18-3058 impeller weigh? The Sierra 18-3058 impeller weighs 0.14 pounds.

Is the 18-3058 a genuine OEM part or an aftermarket replacement? The 18-3058 is a Sierra-branded replacement impeller manufactured to serve as a direct substitute for OMC 983895, not an OMC-branded original part.

What finish does the 18-3058 impeller have? It has a machined finish.

How many impellers come in the package? One 18-3058 impeller is included per package, along with no other components.

How do I know if I need to replace my water pump impeller? Reduced cooling water flow, engine overheating, or a worn/cracked impeller vane on inspection are signs the OMC Sterndrive/Cobra water pump needs a new impeller such as the 18-3058.

Does the 18-3058 include a UPC for reordering? Yes, the Sierra 18-3058 impeller carries UPC 030999315144.

Can I cross-reference the 18-3058 by the OMC part number? Yes, searching OMC 983895 will identify the Sierra 18-3058 as its replacement impeller.

Does the 4.3L fitment for the 18-3058 have any exceptions? No exceptions are listed for the 4.3L (1986-1992) application; the short-impeller exception applies only to the 2.3L and 3.0L engines.