From Imperial Armour:
There are many rituals surrounding the construction, maintenance and use of Rhinos. They must be cared for using the correct liturgies of maintenance, divined from the runes of engineering and the Machine-Spirit must be blessed to protect both the vehicle and its occupants in battle.
When armoured panels are made, they are inscribed with protective sigils:
The Techmarine builder calls upon the Spirit of the Machine God to invest the Rhino with power. Three- times the Runes of Activation are hammered onto the engine block; the engine is fired as the third blow is struck. If it roars into life first time then it is a good omen, the vehicle will live a long and useful life.
We all know the importance of naming your vehicle:
The final blessing is the Naming Ritual. A new vehicle must have a battle name worthy of the Chapter's great history. This name is recorded, and some Chapters choose to paint or engrave it onto the Rhino.