I'm planning to pump lava through teleport pipes. I'll be using redstone engines to do the pumping. I am concerned as to what will happen if there is still lava left to collect, but my tank on the other end of the teleport pipe is full? Does the pump stop safely?
Redstone engines are completely safe, and cannot explode or overheat. If they have nothing to pump, they will actually speed up! (Although they will slow down again when they come under load).
If the liquid has nowhere to go, it will back up in the pipe. The engine will continue to pump, but this won't damage anything, and you won't lose any liquid.
Long story short: Turn on your redstone engines and forget about them.