Found this clear and informative post at:

http://m.truckinginfo.com/article/17935 ... y-coolants

In my CRD I've opted for CAT-rated, red-colored, NOAT coolant. It appears that it is a step up from HOAT and one down from OAT , NAPA SKU#74804-03298 (currently in MX., no PART# here).

Anybody see any reason NOT to use OAT or NOAT-rated coolants beyond HOAT? They appear to possess all the same anti-cavitation and thermal properties of HOAT, with the added benefit of extended time between changes. Big-truck stuff...

Keywords: anti-freeze, replacing coolant, identifying coolants, right anti-freeze for CRD

_________________
'15: bought '05 w/138k.
'16: HG/Rockers/ARPs/Thermo/H20pump/TbeltKit/ Seals/ Mounts/Kennedy fuel pump.
'17: bought manual Gas donor for its' ARB F/R Airlockers, OME 2.5" lift (gas-rated), JBA UCAs, ARB bumper.
'19: Trans w/Suncoast/Transgo/HDdiscs, new OME CRD-rated lift, electric tri-fan setup, BlackMagics/Centric Premiums, Airbags.

The article states that HOAT is not compatible with NOAT.

I imagine that if you flushed all the HOAT out of your cooling system then you should be fine.
So the question is, did you get ALL the HOAT out of it?

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U.S. Army Retired

...and is NOAT compatible with all the materials used in our cooling system? Unless you have a really good reason to deviate I'd tend to stick with what the manufacturer recommends. I've not seen any evidence that HOAT serviced at the recommended interval causes any issues.