Maintenance Tip of the Week: Raw water pump 10/19/2015

Maintenance Tip of the Week – Raw Water Pump 10/19/2015

The raw water pump on your engine is critical for the cooling system. Under heavy load, your engine’s raw water pump can fail, making inspection a critical maintenance task. Always check for corrosion, leaks, and seal before operating your engines and as part of Marinediesel’s recommended maintenance schedule.

Maintenance Tip of the Week – Exhaust Risers 10/12/2015

Maintenance Tip of the Week – Exhaust Risers 10/12/2015

Always inspect your exhaust risers and gaskets for corrosion as stated in your manual’s maintenance schedule. Exhaust riser failure is a leading indicator of critical, and very expensive, engine damage.

In the Tropics? Keep your engine running cool

Tropical conditions are challenging to marine engines. Engines require both air and water for cooling, both of which act efficiently in removing heat. However, in the tropics, the warmer air and water temperatures reduce the efficiency of your cooling system. So, what can be done?

Marinediesel takes the first step in rating your engines for the operating climate. This is one of the benefits of using Marinediesel’s VGT Series: our NIRA ECU allows such changes in rating, avoiding the sometimes large loss in horsepower often shown by the engines made by our competitors.

What can you do?

  1. Check the raw water intake and make certain that the seacock is opening / closing properly.
  2. Make certain coolant levels are topped up.
  3. Check your strainers for debris or blockages.
  4. Check your exhaust system to make certain there are no blockages.
  5. Make certain the air filter is clean and there are no blockages.
  6. Keep your fuel tank topped up. Warm weather increases condensation in the tank and thus, the likelihood of introducing water in the fuel.
  7. Make certain that the louvers venting into the engine compartment are not blocked and that there is adequate ventilation. If not, a blower may be required in extreme conditions.

All of this sounds like basic maintenance procedures, and much of it is detailed in your engine manual. It just pays in the long run to pay extra attention to these items if the vessel will be operated in harsh conditions.

How does a heat exchanger work?


Your engine’s cooling system is highly critical; the combustion process produces an enormous amount of heat, and that heat must be removed or dissipated. If heat is not removed, cylinder and engine block damage may quickly result.

Heat exchangers cool the engine, but work a little differently and more efficiently than a simple raw water cooling system. A heat exchanger consists of a series of tubes, or coils, that fluid flows through. This fluid is enclosed (either cooland or distilled water). Additionally, marine heat exchangers are encased by a jacket, through which raw water (fresh water or sea water) flows through, cooling the enclosed fluid, removing the heat, and exiting the system through the exhaust. The minerals in sea water mean that scaling, or build up, can occur, which is why heat exchangers usually require periodic maintenance. Mineral build up drastically reduces the efficiency of the heat exchanger and thus, the cooling capacity.

This is also why a blocked strainer or faulty impeller quickly damages an engine. When blocked by debris (especially plastic bags), without the raw water to cool the enclosed system, the engine quickly overheats, sometimes in a matter of mere seconds.


Maintenance Tip of the Week: Heat Exchanger 06/01/2015



Maintenance Tip of the Week – Heat Exchanger

On MarineDiesel engines, removing the heat exchanger for cleaning is a big job, one best done during overhaul. Heat exchangers develop scaling and corrosion over time and must be periodically cleaned. Unlike on older diesel engines, this job is best performed by a trained MarineDiesel distributor.




Maintenance Tip of the Week: Impeller 05/25/2015


Maintenance Tip of the Week – Impeller

Impellers should be replaced according to the schedule in your manual. Impellers tend to wear out and no longer pump water efficiently over time. When replacing the impeller, a coating of olive oil can help seal the pump.





How to destroy your marine engine in one easy step


The picture above is of a cracked piston that was part of the engine on a military vessel. The reason that the piston cracked was the failure of the engine cooling system. Why did the system fail?

It was a simple reason: A plastic bag.

The vessel was operating in an area that had quite a bit of rubbish in the area. A plastic bag blocked the raw water intake and strainer, the impeller failed, and the engine overheated, resulting in the severe damage pictured above. The problem with plastic bags, on top of the obvious environmental issues, is that not only are they difficult to see, especially when traveling at high speeds, but that they float, thus making them easy to get stuck in strainers or block intakes.

What is interesting is how quickly engine damage can result from this situation. The intake on this vessel was blocked for perhaps 15 seconds. Engines produce an awful lot of heat, and it is necessary to remove that heat. When the cooling system stops functioning, even briefly, damage is certain to result. The damage above was extremely costly to repair, requiring, effectively, a complete rebuilding of the engine since the cylinder walls were damaged. This does not take into account the costs of the vessel downtime, which can be substantial on a commercial or military vessel.

So, what should you do?

  1. If you will be operating in areas with a lot of rubbish, pay particular attention to the cooling system.
  2. Monitor your pressures and temperatures. Do not ignore any alarms.
  3. Shut the engine down immediately if you sense the intake or the strainer is blocked.
  4. If there is no blockage, then a faulty water pump is the likely cause.




Maintenance Tip of the Week – Heat Exchanger 03/16/2015


Maintenance Tip of the Week – Heat Exchangers

Periodically inspect and clean your heat exchangers as detailed in your MarineDiesel manual. Corrosion and scaling can build up over time, and the heat exchanger is a vital part of your engine’s cooling system.



Maintenance Tip of the Week – Water Pump 03/09/2015


Maintenance Tip of the Week – Water Pump

Always check the seals on your water pump and ensure that the drain and intakes are free from debris. Water pump failure is commonly associated with blocked or damaged impellers.


Maintenance Tip of the Week – Hoses 03/02/2015


Maintenance Tip of the Week – Hoses

The hoses on your cooling system have a life span of approximately three years, after which they need to be changed. Their material can degrade over time in the marine environment, and a burst hose can quickly lead to severe engine damage.