Radiator Coolant Flush
When we decided to flush and fill our coolant we knew we were in for a chore. Our system holds approx 16 gallons of coolant, thats a lot to drain, recycle and refill.
It gets worse, we suspected that the previous owner had mixed coolant chemistry (SCA and OAT) and that is very bad. Also at one point the system had Bars Leaks added, before the radiator recoring, but you can see it in various other areas of the coolant system, such as the transmission cooler (picture)
In order to return this back to normal we had to Empty -> Flush with Fleetguard Restore Cooling Cleaner -> Empty -> Fill with Deionized Water -> Empty -> Fill with the proper Coolant mixture. Each Empty would get ~10-12 Gallons of fluid out, in order to properly dilute/flush what was in there requires one to do multiple fills and flushes.
The radiator petcock does a pretty good job of emptying the system. I found fully airing up the coach allowed me room to slide a 24 Gallon storage tub under the petcock to catch the 10-12 gallons that drained. The tub made for a convenient way to transfer the fluid into waiting jugs and then off to recycling.
When it comes to filling the system, we used a vacuum tool that was recommended on ForeForums Site, a must join site for great knowledge and support! The tool we purchased was Coolant System Refiller. Absolutely not a tool you would think you would ever need. I’ve never needed one. BUT once you use it you will never pour antifreeze in again. They work so well at evacuating every air pocket and bubble.
The tool pulled a vacuum quickly and only a little more, if any, liquid would comes out the vacuum hose. I would achieve a vacuum of around 25 on the gauge and that’s about as low (high) as it would go. Importantly I had zero airlocks so I had confidence that I was pumping coolant immediately and the thermostat was immersed in coolant. Once I started siphoning the new coolant in it would easily pull in 10+ gallons or so before I ran out of vacuum. This was the same as what I drained so I knew it was full with little chance of any air pockets.
I found the 40mm insert fit best in the neck opening, you have to push it over and down to seat in in to the neck. The head / venturi / gauge clears the engine cover and we pulled -25 on the gauge and proceeded to full the system. It was a bit awkward to read the gauge but doable. This filler is awesome, I could not imagine having to do that by pouring 30+ jugs of coolant down the filler neck.
