Engine noise is often one of the most critical criteria demanded by MarineDiesel customers. With military or government users, reduced noise is often essential to the successful completion of missions. On commercial or recreational projects, noise has an enormous impact on passenger or crew comfort, and is often regulated in some areas. Few things can be as irritating as being stuck on a boat with a noisy engine.

All engines produce noise to some degree. It is the level of noise that is critical.

Silencing equipment, vibration, engine mount type and quality, insulation, combustion, and the length and type of exhaust all impact noise levels. Vessel speed and sea state have an impact. Indeed, even the material of vessel construction has an effect, since metallic hulls produce more noise than resin or grp hulls.

Controlling noise starts with the engine. Reducing vibration will always result in lower noise levels. Using the proper engine mounts goes a long way towards controlling noise. At MarineDiesel, we have the facilities that allow us to test and control noise by duplicating real-world conditions. We often will test multiple silencers, engine mounts, or exhaust layouts exactly as they will be constructed on-site. This allows us to make changes to not only the type of equipment, but to the engine itself that can mitigate excessive noise.

This engineering goes beyond simply using one brand of silencer over another. In fact, we can let the customer know exactly how the noise can be controlled.

We have designed engines and exhaust systems that produce under 50 dB of noise at 2 meters. This is impressive by any standard.

This service and capability is one thing that sets MarineDiesel apart from our competition.

This engineering and quiet operation is one of the first things that our customers tell us when they sea trial. MarineDiesel manufactures one of the quietest engines in the market.


Maintenance Tip of the Week – Oil 06/02/2014


Maintenance Tip of the Week


If there is engine noise at startup, but it only lasts a few seconds, this could indicate using oil of the wrong viscosity. Always use the proper viscosity of oil as indicated in your owner’s manual.

Ask Professor Diesel 04/28/2014 – Engine Noise


This week’s question comes from Ibrahim in Indonesia about engine noise

Dear Professor Diesel:

We installed your MD170 engines two years ago, and they have been working great. However, recently, they seem to be very noisy. Is this normal? Are there ways to correct the problem?


Engines can get noisier over time, especially with heavy use. The reasons why can come from a variety of sources:

  1. Vibration over time loosens bolts, fasteners, and belts
  2. Fuel and oil filters have not been changed according to the schedule listed in your manual, or you have been operating with dirty fuel
  3. The engines are using the wrong fuel
  4. Oil has not been changed
  5. The engine timing is off
  6. The injectors are dirty

With the limited information you provided, it sounds as if your engine is ready for overhaul. How long has it been since this was done? If the engine was recently overhauled and mechanical causes can be eliminated, a variety of noise reducing methods are available, such as:

  1. Insulating the exhaust.
  2. Adding silencers.
  3. Changing the exhaust configuration.


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