What Happens When a Marine Raw-Water Impeller Fails? #
The raw-water impeller is a relatively small part, but it performs one of the most important jobs in a marine diesel cooling system.
Its job is to pull seawater into the cooling circuit so heat can be removed from the engine.
When the impeller begins to fail, cooling-water flow can drop quickly.
How Marine Impellers Fail #
Flexible rubber impeller blades can:
- Harden
- Crack
- Tear
- Become permanently bent
- Separate from the hub
- Break into pieces
Age, heat, extended periods of inactivity and normal operation can all contribute to deterioration.
What Happens After an Impeller Fails? #
Reduced raw-water flow can cause:
- Rising engine temperature
- Overheating alarms
- Reduced exhaust-water discharge
- Generator shutdown
- Potential engine damage if operation continues
But there is another important concern.
Missing Impeller Blades Can Travel Through the Cooling System #
Broken pieces do not simply disappear.
They may travel downstream and become trapped inside:
- Cooling hoses
- Oil coolers
- Transmission coolers
- Heat exchangers
- Other cooling passages
Installing a new impeller without locating missing pieces can leave a restriction in the cooling system.
The engine may continue overheating even though the pump now contains a brand-new impeller.
Preventative Impeller Replacement #
Service intervals vary depending on manufacturer, pump design and vessel usage.
Regular inspection and preventative replacement can reduce the chance of unexpected impeller failure.
Learn more about our Marine Diesel Cooling & Raw Water System services.
Need Impeller or Raw-Water System Service? #
All Tech Diesel provides mobile cooling-system and raw-water service throughout Southwest Florida.
