Is  It Time To Change The Water Pump On Your Cummins Engine?

Your Cummins marine engine relies on both freshwater and raw water pumps to maintain proper cooling, helping to prevent overheating and ensuring smooth operation. Over time, these pumps can wear out, leading to potential engine issues. Knowing how to spot the signs of a failing water pump can save you from costly repairs or engine failure.

Here’s a guide to identifying symptoms of a failing water pump, specific to freshwater and raw water pumps, and what to do if you suspect an issue.

1. Signs of a Bad Freshwater Pump

The Cummins freshwater pump circulates coolant within the engine, controlling internal temperatures. Signs of a failing freshwater pump include:

a. Coolant Leaks

Coolant leaks are one of the most common signs of a failing freshwater pump. A bad seal or worn-out gasket can cause coolant to leak from the pump housing. If you notice puddles of coolant under your engine or the coolant level is consistently low, it could indicate a problem with your freshwater pump.

b. Overheating Engine

If your engine is running hotter than normal, it could be due to a failing freshwater pump. When the pump fails, it can’t circulate coolant efficiently, causing your engine to overheat. You may notice temperature spikes on the gauge, especially during long or heavy loads.

c. Steam or Coolant Smell

An unusual smell of coolant or seeing steam emanating from your engine compartment can indicate a leaking or malfunctioning freshwater pump. Coolant can seep onto hot engine components, causing it to vaporize and produce a distinctive smell.

d. Squealing or Grinding Noises

A worn-out freshwater pump may produce a squealing or grinding noise due to failing bearings or a loose belt. If the bearings wear out, the pump pulley may wobble or not spin correctly, which can cause noises as well as overheating.

2. Signs of a Bad Raw Water Pump

The Cummins raw water pump draws water from outside your boat (seawater or lake water) and circulates it through the cooling system. This pump is crucial in maintaining your engine’s external cooling. Here’s how to spot issues with a raw water pump:

a. Reduced Water Flow from the Exhaust

One of the most noticeable signs of a failing raw water pump is reduced water flow from the exhaust outlet. Raw water is expelled through the exhaust to cool the engine, so if there’s less water than usual, it could mean the pump is not drawing enough water or the impeller is worn out.

b. High Engine Temperatures

Like the freshwater pump, if the raw water pump fails, your engine may overheat. The raw water pump is responsible for drawing cool water into the system, and when it stops working efficiently, your engine will struggle to stay cool. Overheating can occur quickly if the pump isn’t circulating enough water.

c. Worn or Broken Impeller

A bad raw water pump often has a damaged impeller. The impeller consists of rubber blades that can break off over time due to wear or heat. If you open the pump housing and find missing or broken blades, it’s time to replace the impeller or the entire pump.

d. Corrosion on Pump Components

Since the raw water pump constantly deals with saltwater (in marine environments), corrosion is a common problem. If you notice signs of corrosion on the pump housing or other components, it’s a sign that your raw water pump may be compromised, especially if it impacts the impeller or pump casing.

3. Checking and Maintaining Your Water Pumps

Regular maintenance and checks can help extend the life of both your freshwater and raw water pumps.

a. Inspect Belts and Hoses

Make sure the belts and hoses connected to your freshwater pump are in good condition. Cracked or loose belts can affect the pump’s performance. Similarly, inspect hoses for any leaks or damage.

b. Replace the Impeller Regularly

For raw water pumps, it’s recommended to replace the impeller regularly, especially if you operate in saltwater conditions. A fresh impeller ensures optimal water flow, preventing overheating.

c. Flush the Cooling System

Regularly flush your cooling system with fresh water, especially if you operate in saltwater environments. This helps to reduce corrosion and salt buildup within the raw water pump and other cooling components.

d. Monitor Temperature Gauges

Keep an eye on your engine’s temperature gauges while operating your boat. If you notice any unusual readings, inspect both your freshwater and raw water pumps to identify any potential issues before they escalate.

4. What to Do if Your Pump is Failing

If you suspect your Cummins freshwater or raw water pump is failing, take action immediately:

• Inspect the Pump: Check for visible leaks, worn-out parts, or broken impellers. Replacing the impeller may resolve issues with a raw water pump.
• Replace the Pump: If your pump is damaged beyond repair, replace it with a high-quality aftermarket pump. Diesel Pro Power offers a range of freshwater and raw water pumps specifically for Cummins marine engines.
• Consult a Professional: If you’re unsure about diagnosing or fixing the issue yourself, consult a professional marine mechanic to assess and repair your cooling system. Need Help?

Conclusion

Keeping your Cummins freshwater and raw water pumps in good working order is essential for reliable engine operation. By recognizing the signs of a failing pump and performing regular maintenance, you can prevent overheating and other costly repairs. When it’s time to replace a component, choose high-quality aftermarket parts from trusted sources like Diesel Pro Power to ensure optimal performance and longevity.