Fixing a marine engine and choosing a new one are different missions, yet both land in the marine engines propulsion category. One product here is a replacement part for an existing Caterpillar CAT 3412/C32 cooling-water pump; the other is a complete Yanmar 4LHA-STZP inboard diesel. The right pick depends on whether you need to restore cooling flow or put a whole powerplant into a boat.
Quick Verdict
The headline difference is price. The CAT impeller is listed at $83.24, while the Yanmar is listed at $15,000.00 - a gap of about $14,916.76. Choose the CAT impeller when your current CAT 3412/C32 only needs water-pump service. Choose the Yanmar when your project needs a complete diesel powerplant and you are ready to manage logistics.
At a Glance
| Product | Listed Price | Price Bar | What You're Buying |
|---|---|---|---|
| Inboard Marine Engine Water Pump Impeller for Caterpillar CAT 3412 C32 1539123 | USD 83.24 | Impeller kit for a CAT 3412/C32 cooling-water pump | |
| Yanmar 4LHA-STZP inboard marine diesel engine tested ok - Ship by sea | USD 15,000.00 | Used 200 HP inboard diesel, no warranty |
Where Each Product Wins
The CAT impeller wins when the goal is repair: it is a new part, comes as a flexible impeller kit, and uses a spline drive with a brass insert. The Yanmar wins when the goal is a whole powerplant: it is a complete marine diesel rather than a replacement component. If your cooling system is the only issue, the impeller solves it; if you need an engine, no impeller can replace that.
Product Notes
Inboard Marine Engine Water Pump Impeller for Caterpillar CAT 3412 C32 1539123
This new impeller kit is aimed at the CAT 3412/C32 cooling-water pump. It uses a spline drive and a brass insert, and it comes as a flexible impeller kit. The part carries OEM numbers 1539123 and 1566892 and is used on CAT pumps 147-7850 and 212-7264. For someone with this engine already installed, it is a direct repair item for the water pump, with a 1-year warranty backing the new condition. The limitation is fitment: you still need to confirm your engine model, serial number, year, and horsepower before ordering, because the impeller must match the pump on your actual engine. It will not add horsepower or replace a worn engine block; it only serves the cooling-water pump.
Yanmar 4LHA-STZP inboard marine diesel engine tested ok - Ship by sea
This is a complete used inboard diesel of Japanese origin, rated at 200 HP, with a 4-stroke design and the model number 4LHA-STZP. The Yanmar is marked tested ok and is described as a good-working used product. It ships by sea from Sabarmati ICD in India to the nearest sea port terminal. The strength of this option is that it gives you an actual powerplant, not just a service part. The trade-offs are real: no warranty, used condition, and buyer-managed customs clearance, including mandatory ISF filing for U.S. sea ports before the container leaves India. Local port charges will be on top. This choice is for a buyer comfortable with ocean freight and import paperwork.
Final Choice by Use Case
If your current CAT 3412/C32 is already in the boat and the cooling-water pump needs attention, the impeller is the focused repair choice. If you need a whole powerplant and can handle shipping, customs, and buyer-managed import steps, the Yanmar is the whole-engine route. Confirm the engine model, serial number, year, and horsepower early in your process; that single step makes it clear whether this is a small pump repair or a whole-engine purchase.
