This is an old thread, but here goes:
, Texaco 2997 (now part #222997), is an NOAT, that is a Nitrited (not NitrAted) Organic Acid Technology. As far as I know, almost ALL of the these NOAT Extended Life Coolants (Shell Rotella ELC, Mobil NOAT ELC, Delo ELC, Final Charge NOAT) are made by Old World Industries a/k/a Peak Industries.
Here is a VERY comprehensive cross-reference chart:
states it is important to use a NITRITED OAT formula to avoid "cavitation pitting" on the various aluminum parts
in the engine
. These are tiny bubbles caused by the cylinder walls that cause microscopic bubbles to form and collapse with thousands of PSI against the metal, hence the pitting.
I found Mobil Delvac NOAT, but it is EXACTLY the same as the others shown in the chart because they ALL come from the same vat...this is confirmed by Mobil and Old World.
They all state that the NOAT ELC is good for minimum of 600,000 miles or 12,000 hours (for heavy duty diesels such as trucks or earth-moving equipment), for what it's worth...
The official Yanmar bulletin recommending an ELC is attached...
Hope that helps.