Took my 2004 G35 Base to the mechanic to get the cam shift sensors replaced. I pick it up and drive it home. The next morning while heading to work the car overheats so I go back to the mechanic and he tells me that the radiator is busted. I cant prove it, but how likely is it that he did it while performing repairs on the engine??

 

Really not likely. That Cam-pos sensor is on the back of the block and the radiator obviously in the very front of the bay. Assuming it's the original radiator, I'd just say it was probably just time. 12 years of heat cycles under the hood makes the plastic of the radiator very very brittle. Mine cracked about a year and a half ago after I literally tapped my tire on a curb.

 

I have to agree it's hard to mess up the radiator changing those sensors. Unless, someone is in there wildly swinging with tools. Mine was seeping on the bottom plastic, so I replaced it with a 60 dollar one from eBay.