Mech fluid

Mech fluid is a substance that exists in Transformers, at least during the Beast Era. It seems to be analagous to blood in conversation and metaphor, but its actual function has not been expanded on, nor its link to any of the other fluids Transformers have been seen to have inside them over the years.

Fiction

Beast Wars

When Tarantulas prepared to drain Cheetor, he reminded the Predacon that he had no blood, just mech fluid. Tarantulas explained that he prefered the act to the actual nourishment. That's just gross, even for Tarantulas. The Web

From Teletraan I: The Transformers Wiki, a Wikia wiki.