Engines *can* explode, but it's easily avoidable since even the most basic gate has the power requested condition. If the power grid is saturated, the engines shut off. Still trying to figure out how to set up the proper conditions to prevent combustion engines from exploding.
Edit Again: Combustion engines seem to require gold gates to make them explosion proof, iron and gates cannot tell the difference between the fuel tank and the water tank.
yeah. it's easy to avoid overloading the energy buffer of engines. altho that is a type of explosion that can only happen if you have a full blockage of energy flow. something that never happened back when pipes exploded. when the pipes went boom, the engine on signal would also be cut off if you used a gate to control it. if it was a lever,,, well that is another story. however, with the new pipes and fancy gate conditionals we have now, the signal is not cut when the pipe is "blocked" by having a section in an unloaded chunk. (this might be fixed in newer versions, because i think this might count as a bug imho.)
Something to keep in mind with the kinesis pipes tho. you can have an almost free energy storage device as part of your network, by simply looping your power pipes back to the engine room. the energy network will now store up to the capacity of the pipe type in each and every one of the pipes in that loop. it actually adds up to quite a bit of storage if you have a decently large line of machines along all your walls.