Cat Products

[al_khulaqi]

1- I am having a serious problem with my 3412 Main Propulsion Engines. The liners fail at around 2000 hrs.

2- I was not able to figure out the problem although I am told it is the coolant used.

Q1. What is the level of pH required for such engines working in tropical areas ?

Q2. Would the layout and performance of the cooling system also cause liner failure ?

Q3. What would be your recommendation for a process to identify the cause of the problem ?

[PaulH]

Firstly you need to provide some more information.

                                                                                             Are these engine heat exchanger or keel cooled?

                                                                                             Have you had your coolant tested?  

The cooling system could be to blame and also the coolant itself but for the liners to be gone after just 2000hrs is a bit extreme. Have your engines been checked for earth leaks recently?

[mikel]

Liner damage from cooling system problems is usually due to cavitation erosion.  An excellent discussion of this problem, it's causes and solutions can be found in the CAT publication Coolant and Your Engine, don't have the form number handy but maybe your local dealer can provide a copy.

If your damage is in fact due to cavitation erosion, first you need to assure the coolant you're using is suitable for a heavy duty engine.  This is important, since coolants formulated for automotive engines typically have high silicate levels and don't protect against cavitation erosion.  Your engines Operation and Maintenance manual has information on CAT specifications for water used in cooling systems and for the coolant.

In general, minimum acceptable water used in cooling systems should meet the following,

Chloride, 40 ppm max

Sulfate, 100 ppm max

Total hardness 170 ppm

total solids, 340 ppm

pH, 5.5-9.0

From LEBV0915, Engine Installation and Service Handbook

In a properly designed and maintained cooling system, while not preferred by CAT, plain water and a proper corrosion inhibitor is acceptable and in use succesfully in many systems.

Has a cooling system audit been performed?  Improper coolant flow rates and system pressures can also cause cavitation erosion.  There is a CAT EDS sheet on cooling system audits, also the publication LEBV4830, Marine Analyst Service Handbook also has some very helpful information of marine engine cooling systems.

First, properly indentify the failure mode of the liner

Second, verfiy the suitablity of the coolant for a heavy duty diesel engine

Third, perform a proper cooling system audit to assure overall cooling system design is to CAT and industry standards. You will need TMI information on the engine cooling system components, such as pump

curve(s), performance of heat exchanger and aftercooler cores, etc.  And I would strongly recommend you get a copy of the Marine Engine Application and Installation Guide, at least the cooling system portion, should be able to get from your local dealer.

Mike L.