wondering what would have caused this

[linadin]

this is a 871. but it was also between 3 and 4. i am still thinking it was something they did when they put the new head on last feb. it only has about 70k miles since. i am already takeing them to court over a clutch they put in incorrectly so it would not suprise me if it was inproper torqe or even damageing the head gasket as they were putting the new one in.