From what I understand, the military uses conventional green antifreeze; cheap, plentiful, simple. The problem with it in the diesel world is complex yet simple, see excerpt below. The military is aware of the problem and simply doesnt care to address it, just like they continuously blow up Detroit 2 stroke diesels running 15W40 when Detroit mandates straight weight oil because “We do not want to complicate our supply chain”
“Cavitation is the phenomenon in which vacuum bubbles are created in a liquid due to an external force. A common example of cavitation is the bubbles that emerge from the prop of a boat; they are in fact small pockets of vacuum, not air. These pockets are created when forces are rapidly applied to a liquid. In a diesel engine, cavitation is created when the cylinder walls rapidly expand and contract under the immense pressures created in the cylinder. At 2,000 rpm, each piston in an engine is moving nearly 34 cycles per second (the piston is moving down, then up 34 times per second), which translates into nearly 9 power strokes per second. In effect, this cyclic motion creates a vibration that causes a small vacuum pocket to form between the engine coolant and cylinder wall. The problem with cavitation is that the vacuum area must dissipate, and when it does so the engine coolant slaps against the outer cylinder wall. While the force against the wall is low, it occurs continuously and slowly erodes away the cylinder wall. Over time, the cylinder walls can wear to the point that a hole or crack will propagate. Coolant in the engine oil and/or engine oil in the coolant is often a sign of a hole in the cylinder wall for engines that are prone to fatigue failure due to cavitation.”
The conventional green coolant lacks proper SCA (Supplemental Coolant Additives) to protect cylinder liners, couple that with them quite often failing to service a truck later in life sitting at the back corner of base or local guard unit and you start accumulating corrosion related to the breakdown of coolant failing to protect parts.
So how do we fix this?
A full cooling system flush is in order, flush forward flush backwards with an actual coolant flush chemical if you wish, you can do it 100 times and you’ll never ever get everything out no matter how hard you try, I promise you that you’ll never ever ever get all the crud out, and your aftercooler is caked in the crap too. You truck desperately needs (2) things afterwards:
1) You can continue to use conventional green, or a diesel rated coolant; The latter of which I recommend more. If you decide to use conventional green, you must add SCAs, if you use diesel rated coolant with SCA additives already added that’ll work too.
2) add a coolant filter, it’s less than $100, will save water pump wear catching particles smaller than your eye can see, and replacement filters are less than $10 each at times, you can even purchase filters with SCA maintaining additive packages inside them.
If you’re installing the filter, simply T it in bypass style into both heater core lines, that way when it clogs you won’t build excess pressure or loose heat capacity of said heater core, also add cutoff valves on both sides of the filter so you can easily shutoff and replace filter without having to drain 5 gallons plus of coolant. Replacement is 2 minutes max.
