It is likely to contain information warning the ground crew to be cautious of steam when the engine is hot and as you state information regarding the Glycol mixture. These inscriptions varied with the exact wording used, but they generally all mentioned the above information in a roundabout kind of way. Sometimes just the Glyol info... Some quite lengthy like the example you have posted above and some quite short and basic. Sadly unless a better photo can be found showing the text on the aircraft you posted it may be impossible to get the exact wording that they used in that instance correct.
