[Richard]

Brad,

This coolant business is one of the most maddening things in the RV diesel world. Let me see if I can't give you
Richards version. All engine coolant is ethylene glycol. Ethylene glycol is clear. The sleeved cylinder liner engines require some sort of chemical to keep bubbles from forming on the coolant side of those liners. The bubbles collapse, called cavitation, and the bubble collapse eventually etches away at the liner. The old school original coolant had nitrates added to it to control the collapse. Those nitrates were consumed over time. Therefore, the coolant was monitored for nitrate levels and the nitrates could be topped off with supplemental chemical OR more commonly coolant filters that contained supplemental additives. You have seen this as SCA, supplemental coolant additive. In addition the anti corrosion chemicals can deplete in the coolant over time. A long time ago, the nitrate based coolant was green. Life was simple then.

But since the coolant had to monitored, and lack of monitoring and control led to bad things, the coolant manufacturers developed alternate technologies that did not deplete as rapidly. The first was OAT, organic acid technology. This is generally referred to as ELC, extended life coolant. In the very beginning it was generally colored red. It did not need monitoring, and is generally advertised as having a 3 to 5 year lifespan before and extender can be added to give another 3 to 5 years.

You do not mix the two coolants.

Life was still good, until HOAT, hybrid organic acid technology, and other variants came along. With all of those variants came pink, orange, and yellow dyes for the coolants with no standardization among manufacturers.

So why did I drag you through this? To make a simple point. If you don't know for an absolute certainty what is in your engine, then flush the system, and refill with a coolant that you can buy nationally. Buy some extra and keep a couple of gallons with you. Write down what you have, and how it should be monitored and maintained. The really really bad thing about all the variations out there is that there is NO way for the common guy to test and know what he has. Color is not a foolproof indicator.

As far as disposal, please don't dump it down the drain. Take it to any major place that does general car service work. They collect their antifreeze, and either sell it to recyclers or simply filter it and use it to refill cars they service. Ethylene glycol does not go bad.


This just my .02, and a very simplified version of the coolant world.