Coolant System Green Goo

[davidbrady]

Be very careful with Prevost Chuck. Prevost uses extended life coolant exclusively. If you ask them to top-up your cooling system the tech will probably pump ELC (OAT) coolant into your system screwing up your chemistry.

My bus had standard coolant in it when I purchased it. Prevost in Richmond, BC checked it and replaced the NalCool 3000 filter. During my 4500 mile trip home my DDEC coolant temperature sensor went bad. I stopped in Prevost (Nashville) for a new sensor. In the process they dumped probably 15 gallons of a 20 gallon system. They filled it with ELC (OAT). I thought nothing of it because I knew I'd be converting to ELC anyway. I asked them for a blank filter. They said they had none. I left it at that. I just now checked the receipt from 3 years and 15000 miles ago and I see they charged me for a new NalCool 3000 filter which I would not let them put on if I knew. Goes to show you need to watch these guys at every step.

Anyway, I know ELC coolant can tolerate 25% dilution by standard coolant, so I wasn't concerned about silicate dropout; frankly, I believe the silicate dropout occurred before I bought the bus when it was running standard coolant because ELC is silicate free. In reality, I have no idea what folks poured into it over the years, and I'm definitely remiss in not doing a total coolant system flush 3 years ago when I bought the bus.

Yesterday I pumped 45 gallons of fresh DD PowerCool ELC (OAT) through my system and renewed the filter with a blank: Wix: 24070. So I now have pure ELC but I also know there's a silicate dropout (green goo) film covering at least parts of the cooling system.

I may dump the coolant and save it so I can pour it back in, and remove the transmission cooler for inspection. This is the prudent thing to do. I'm going to try hard to do this before our trip.