I have a VW Citi Golf, and the Welch plugs on the engine block suddenly started leaking water. The engine sounds fine, but it obviously leaked a lot of water and although I didn't drive far, I'm not sure how long ago this happened.
The mechanic seems to think they just need to be replaced, but what would cause this to suddenly happen? I'm imagining the the block heating up so much it warped. Are there any less possibilities?