block heater popped out, now have a ticking sound

I was on the highway the other day and after driving a few minutes I noticed a slight loss of power and assumed it was just the wind I was driving into. I could then hear a slight ticking which eventually became louder quite quickly which made me look at the guages and saw the engine light on ...pulled over immediatly and noticed the engine had died. Had it towed to the garage and found out the block heater had popped out and the coolant had drained. I had not driven more than a few hundred feet from the time the ticking became quite noticeable until I pulled over and let the smoking antifreeze blow away. There was antifreeze all over the engine and all underneath to the bumper. After all was said and done, I went and picked my truck up and on the way home I heard a ticking/tapping sound which increases with acceleration AND is faintly present at idle. Present upon starting to. I was told the ticking I heard when I pulled over was from the water pump going dry. Could this still be the same noise? I'm pretty sure the engine didn't overheat at the time as I said it happened fairly quickly and it was cool out and none of the guages caught my eye as being out of place. When I stick my head over the engine it sounds mostly from the front/right side. It has its usual noises and little rattles but this is definetly not one of them. '03 prerunner. 168000 km. Its not a sharp tick/knock but not a hissing/leak tick either....somewhere in between. If I couldn't hear, everything else is fine. I have time to take it back in in a couple weeks but would appreciate some info or suggestions as to what it might be and if its something I could drop off at my brothers to investigate or fix.