On page 74 of the WRV owners manual it states "Coolant levels should be replaced every two years to prevent build-up of harmful chemicals".
This statement is what saved us as the insurance person stated that we had to show that that we tested and changed the coolant every year when we changed the oil. They had to go along with the owners manual statement. We had luckily changed the coolant at two years and were having it checked at 4 years when the leak was discovered.
I gave a complete copy of our owners manual to EM about a year ago and I believe it is available on the ACA site.
Jerry & Judy, Fremont, California
2017 Dutch Star 4018
Freightliner, HWH Active Air