My father-in-laws Buick with 46,000 miles started running hot and the heater wouldn't put out much heat.I took a look at it for him and the cooling system was full of pinkish-orange jelly.It took the Buick dealer three vigorous flushes to clean out so we could put real anti-freeze in it.
The last big truck that I bought was a Volvo with a Cummins engine.The first time I took it to the Cummins shop they were horrified to find it had Dex-cool in it and told me to get it changed immediately.With that stuff in there,getting warranty work from Cummins would be a chancy affair.
That's my experience with Dex-Cool.

Paul,
Boonville,MO