
Sandbar parties are fun, but they pose a hidden potential danger to your boat: sand intrusion into the cooling system. This can lead to restricted water flow and, eventually, engine overheating. Here’s what to watch for and the maintenance issues that can arise:
Signs Sand May Be Causing Overheating:
- High Engine Temperature Gauge
- First and most obvious indicator — keep an eye on your temp gauge.
- Reduced Water Flow from the Tell-Tale (“Pee Hole”)
- On outboards, a weak or erratic stream suggests a clogged water passage.
- Steam or Smoke from Exhaust
- This usually means the engine is not cooling properly.
- Warning Alarms or Limp Mode
- Many modern engines will sound an alert or limit power if overheating is detected.
- Performance Loss
- An overheating engine might bog down, especially at higher RPMs.
Common Maintenance Issues from Sand Intrusion:
- Clogged Water Intake Screens
- Sand can block screens on the lower unit or intake ports.
- Worn or Damaged Impeller
- Sand is abrasive and can wear down the impeller blades faster than normal.
- Clogged Thermostat Housing
- Fine sand can get stuck around the thermostat, causing it to stick open or closed.
- Restricted Water Jackets
- Over time, sand buildup in the internal cooling passages reduces water flow.
- Damaged Water Pump Housing
- The sand wears down the housing and impeller plate, reducing pump efficiency.
Preventative Tips and Maintenance:
- Flush the engine thoroughly after every sandbar trip, especially in shallow or silty water.
- Inspect the tell-tale stream before and after every outing.
- Change the water pump impeller annually or as recommended — sooner if you boat in sandy areas.
- Use a flushing kit (muffs for outboards, in-hull flush system for inboards) after use.
- Have the cooling system inspected regularly — a mechanic can check for internal blockages with a borescope or pressure test.
Bonus Tip:
If you’re idling in shallow water at a sandbar, trim your motor up slightly to reduce the chance of sucking sand — but not so much that the intakes are out of the water.