Hard Coolant Lines Are Best For Longer Runs.

Cooling System Failure

Most engine failures are coolant related, so mastering your coolant program is by far the most cost-effective way to extend engine life.

What happens when coolant isn’t maintained? Cavitation erosion (CE) begins causing liner pitting, CE is triggered by cylinder liner vibration as the engine fires with every power stroke. These vibrations occur when the liner expands during firing, and then quickly snaps back to its original size as the pressure drops. When the liner snaps back a low-pressure area develops in the coolant, and voids form in the coolant next to the cylinder wall. The forming of the voids and their rapid collapse begin to erode the cylinder liner and can penetrate the cylinder in under two hundred hours of operation-with straight water in the cooling system.

The cooling system conditioner contains nitrite. When nitrite is present in the coolant, it puts a tough nitrate coating on the liner which protects the metal from damage. As the constant vibrations continue, the nitrate is blasted away and replenished by nitrite in the solution. Need release coolant filters help maintain coolant pH. MER Need release filter systems are available for all engines-Diesel or gasoline.

As long as there is a concentration of 1200 parts per million (PPM) in the coolant, the liners are safe.


The natural tendency of all metals exposed to oxygen is to oxidize and revert back to their “ore form”. Keeping the coolant near a neutral pH; not too acidic and not too alkaline, will help protect all of the metals in the cooling system. The method of choice for controlling pH in many heavy-duty diesels is to add borate, a chemical that buffers (keeps the pH between extremes of acidic or alkalinity). Maintaining your coolant makes hoses last longer. Speaking of hoses, MER now carries the Parker Easy-Form hose that will replace many pre-formed hoses. (Easy-Form hoses come in diameters from 1/2″ inch to 4″.)

Scale-Heat is the by-product of making power.

Diesel engines produce huge amounts of heat that must be quickly transferred so that pistons do not melt-down or over-expand. Using even good drinking water that contains minerals like iron, calcium and magnesium in the cooling system will cause scale.  Scale and minerals also damage water pump seals. Unfortunately, scale is also an insulator which reduces heat transfer, and this can result in severe engine damage. Using de-mineralized water in the cooling system is extremely important to ensure the pH of the coolant doesn’t get too high (alkaline) because high pH also causes scale. Testing to maintain borate levels in the coolant will reduce scale.

Drop Out-This green “goo” or paste will form when excess levels of phosphates or silicates are in the coolant. Drop-out compounds like these cause plugging of vital coolant passages. Low silicate, phosphate-free formulations that instead depend on nitrite-boron additives, will stop drop out.

With So Many Coolants and Conditioners on the Market-Let’s Simplify-Several of us have been working on this article, and it began to get extremely complex to tell you how to treat all of the brands and colors of anti-freeze. So, we are going to simplify the approach with the following sentence: If you can’t positively identify your coolant type, drain it and flush the system, and refill with pre-mixed John Deere Coolant. Periodically test the Deere coolant and maintain the system with Deere Cooling System Conditioner. Finish up by testing the freezing protection. If you definitely know what type of coolant you have, then test it and treat it. Use John Deere test strips, and follow the treating directions. Call MER for test strips (PN 701144), conditioner and coolant. Finally, verify the coolant freezing protection temperature, and you are ready for a trouble-free season!

Contact us at 206-286-1817  about getting our technicians to check and upgrade your cooling system.