Many boat owners have a Volvo Penta engine. That’s an excellent choice, but sometimes the water pump can start to leak. Are you experiencing a leaking Volvo Penta water pump? Then you’ve come to the right place. A leaking water pump can cause serious engine damage if not addressed promptly. Especially if you regularly sail in saltwater, you can eventually experience wear, contamination, or a defect in the cooling system. In this article, we will explain how these problems arise, what to look out for, and how to resolve everything with top-quality parts.
Common issues with impeller pumps
The water pump is a crucial part of the cooling system of your Volvo Penta engine. The water pump ensures that cooling water is pumped through the engine, preventing it from overheating. Inside the water pump is an impeller, a fan with flexible rubber blades, which circulates the cooling water.
The water pump and impeller are constantly exposed to water, dirt and temperature fluctuations. Over time, the water pump of a Volvo Penta engine can start to leak. Common causes of leakage include:
- Wear of the shaft seal: The seal prevents water from running into the engine along the rotating shaft. In an old water pump, extensive use in saltwater, or insufficient water lubrication, the shaft seal can wear out. If the water seal is not replaced quickly, the pump shaft can corrode and water can get into the engine oil.
- Clogged weed filter or cooling water supply: A blocked weed filter can prevent seawater from reaching the pump. This causes the impeller to run without sufficient water, leading to overheating and wear.
- Corrosion in the pump housing: Rust and wear can cause metal parts of the casing to deform, preventing O-rings and gaskets from sealing properly and allowing water to leak in through small cracks.
These causes can lead to the water pump leaking and it’s important to intervene promptly. In the following section, you’ll learn how to recognise a leak.
If the pump no longer has sufficient output, first check the following:
- Worn impeller: The impeller forces cooling water through the pump and can wear out or dry out over time. This can cause leakage through the housing or the drain hole of the water pump.
- Broken impeller: A vane can break off or come loose from an old impeller. Rubber particles can enter the cooling system and block hoses, valves, or water pipes, leading to increased wear.
Pay attention to these signs on various Volvo Penta engines
A leaking water pump can often be recognised by various signs. By recognising them in time, you can prevent greater damage to your engine. Also, always check if there is a strong stream of cooling water coming from the exhaust; this indicates a well-functioning impeller.
Five engine warnings are:
- Water drips or a puddle at the pump: Are there any drips or even a small puddle under the engine? Check if water is escaping from the drain hole, lid, or seal. This water loss is often the first sign of a problem with the pump.
- Unusual noises from the water pump: If you hear whining, grinding, or tapping noises, this could mean a bearing is worn or a shaft has seized. This also increases the chance of leakage.
- Overheated engine or warning light: If the coolant flow decreases, the engine will overheat faster. You will notice this through a loss of power and possibly a warning light illuminating.
- Foul smells from standing water: With a prolonged leak, water will accumulate around the engine. Standing coolant in the bilge can cause an unpleasant odour.
- Water in the engine oil: If the oil is creamy and starts to look like mayonnaise, water has got in. This water can enter the crankcase, which reduces lubrication and can lead to serious engine damage.
If you recognise any of these signs, it’s important to act quickly. In the next section, you’ll read how to solve the problem.

Solutions for leaks on Volvo Penta engines
Leaks from a Volvo Penta engine’s water pump are often caused by a faulty seal or a worn impeller. The seal, or shaft seal, prevents water from running along the rotating shaft into the engine. Over time, these parts can wear out, causing leaks. In many cases, the entire pump or a complete overhaul kit including the seal and shaft needs to be replaced. Sometimes the pump needs to be dismantled to properly assess the problem.
Have you noticed your water pump is leaking? Then it’s time to resolve this issue. We have outlined a number of steps for you and would like to refer you to our overhaul kits, which you can find on the product page for each specific: Volvo Penta impeller pump or look for complete Volvo Penta service kits for the entire engine maintenance.
Step 1: Stop the engine
You don’t want to sail on with a leaking water pump. Turn off the engine as soon as possible and let it cool down completely before you start your inspection.
Step 2: Check the water pump
Map out where things could go wrong. See where the water is coming from, look for signs of rust or wear and check the pump housing, the seal, the drain hole, the O-ring, and the hoses around the pump. Also, check the engine block for water loss. Don’t forget the impeller either.
Step 3: Replace the impeller
Is the impeller the culprit? If so, you can replace it. Fit a new impeller with plenty of lubricant and always replace the gasket or O-ring to prevent leaks. Note that some parts, such as seals, need to be pressed in for proper operation and sealing. At AB Marine Service, we have the right impeller for every Volvo Penta engine.
Step 4: Replace other parts
Is it not the impeller or are you still experiencing problems after replacing the impeller? Then look at other parts. The seals or shaft seals may be worn. Often these seals and shaft seals are identical in shape and specifications, but they are fitted in reverse of each other. You can also order these parts easily and quickly from AB Marine Service.
Step 5: Replace the water pump or repair kit
If the shaft is worn or the pump housing is pitted or scored, it is wiser to opt for a new pump. Keep in mind that replacing the water pump may depend on how the engine is installed, which affects accessibility and the dismantling of parts. Also, pay attention to purchasing the correct connections and hoses. You are also in the right place with us for a new water pump or a reconditioning kit.
By following these steps, you can effectively resolve water pump leaks on your Volvo Penta engine. In the next section, you’ll learn how to prevent future leaks.

How do I prevent future leaks?
Good maintenance can prevent a leaking water pump. We give you some tips to keep your Volvo Penta engine in good condition:
- Regularly inspect everything: It is advisable to check your engine at least once a season. For example, look at the water pump, the impeller and seals. Look for signs of wear, rust or small leaks. Also check the waterline, as this is important for assessing the cooling system and detecting potential water intake problems. This gives peace of mind, certainty and the opportunity to act early.
- Replace the impeller in good time: We recommend replacing the impeller annually or after 200 running hours and checking the housing. Even if the impeller still looks good, the rubber may have lost its flexibility. Proactively replacing the impeller prevents many potential problems. If you are missing impeller blades, also consider that they have entered the cooling system and are likely still somewhere in the system.
- Keep your weed filter clean: Good flow is of great importance for every water pump. Check now and then to see if your weed filter is not clogged and check hoses and water pipes for blockages. This will extend the lifespan of all parts.
With these tips, you can keep your cooling system in top condition and reduce the risk of leakage. In the final part, you’ll read how to solve problems with top-quality parts.
Resolve all issues with A-grade parts
A leaking water pump is no fun, but with parts from AB Marine Service, you can resolve it expertly. In our webshop, you’ll find water pumps, impellers, seals, shaft seals, and more for various Volvo Penta engines.
Please note: the exact procedure for repairing a water pump varies depending on the engine model. Therefore, always mention your engine’s serial number when searching for parts, so we can help you choose the correct product.
Leaking seals can allow water to pass through, which can lead to water in the engine oil. A new impeller is relatively inexpensive compared to the cost of an overheated engine or a damaged cylinder head. If you find water in the oil, the water pump may be the cause, but also check other potential causes such as the cylinder head gasket. The story that water in oil is always caused by the water pump is not true; get properly informed.
Do you have a question or do you need help at the location where your boat is moored, for example in the harbour or at your berth? Please feel free to contact us. We will be happy to help you find the right parts. This way you can get back on the water carefree with a reliable cooling system.

























