There is no telling where he has gone.
In the above sentence, Is 'telling' noun or participle?
"Telling" here is a verb in the form of gerund-participle. This is a special case where a verb phrase takes a pre-head dependent that is characteristic of the noun phrase structure.
Huddleston & Pullum (2002: 1189) refer to this as a Hybrid Construction. A hybrid construction with "no" is virtually restricted to the there-existential construction.
Another common instance is "there'll be no stopping her". Note that it takes a direct object, a kind of dependent that's only admissible in a verb phrase structure.
Since a participle is a verb form being used as a noun, this is a distinction with little or no significance. Moreover "there is no telling" (meaning there is no way to determine) is an idiom, and as such may violate normal principles of grammar.
idiomatic phrase: There is no telling
to tell here means to discern, to be able to understand a situation.
telling is a gerund noun in that phrase.
I can't tell whether the food is good or bad.
To tell=to discern, distinguish, identify, etc.