[kaptain]

Joe,

The question of which coolant you have is a tough one. If you have any records, then you may be in luck.

The essence of the problem is this. All the coolants are ethylene glycol. The difference is in the additive package which is required to prevent cavitation on the wet cylinder liner in the engine. For years, the coolant used contained nitrates, commonly referred to as SCA’s. Life was good and coolants were simple. The along came extended life coolants using Organic Acid Technology, OAT. The advantage being much longer life, and no need for adding SCAs to the system periodically. Life was still simple because the original coolants using SCA were dyed green, and the new OAT based coolants were dyed red.

Then for some unknown reason, coolant manufacturers started using pink, and orange, and red in coolants with SCA  or in coolants using OAT. The coolant additive packages ARE NOT compatible, and if mixed can cause gelling problems in the cooling system.

This non standardization of colors created a huge problem in the diesel coolant world.

This is an oversimplified condensed version of the situation. I encourage you to spend some time researching this topic before proceeding.

Wait, it gets worse. I am not aware of any commercially available test system that will tell you which of the  additive packages you have.

So, you can’t depend on color. And you can’t easily test.

If you have records, then stay with what the records indicate is in the system. If you don’t have records, then a sample sent to Blackstone or another testing lab may be able to identify what you have. But that is a long shot. Without records, most people drain the system, flush with distilled water, and refill with the coolant of choice. If you do that, please leave records for the next owner.  Like Steve Bare, I use Final Charge OAT because it is available at Walmart.

Wonderful information! Thank you! Richard. 

I don't have a record of this coach, as I haven't owned this 701 coach for long. 
Coach 701 was once Marc Newman's coach, https://newellgurus.com/member.php?actio...le&uid=183
I don't know what year Marc sold his 701. But the owner before me bought it in 2019; his family owns a trucking service business. So he never had to travel to Newell for regular repair or maintenance. I spoke to this previous owner a couple of times. He doesn't appear to know this coach well, he'd refer me to the manufacturer, and he says the factory is based in Miami, Florida. 

However, there is one handwritten mark on the recovery tank, it appears "FAEON 4.0", or "PAEON 4.0". Searching over Intenet doesn't find any sensible results.
Does the marking on the recovery tank mean anything to you?