1999 Volkswagen Passat bent valve

Overheating won't cause valves to bend. Broken timing belt will. If the crankshaft or camshaft is turned while the timing belt is removed (in your case water pump replacement) that will bend a couple valve to the very least, as your engine is interference engine application.

I know this is way late, but you 2 pros are right on the money. I went to do the water pump, and then timing belt because I was there at 140k ( last timing belt was at 80k). My cam spun due to spring pressure and now a few valves are bent. buy the cam locking bracket...it is worth it. Still working on it, but I see one intake valve open on cylinder 6 and the other 2 closed. Just from not locking down the cams with the bracket.