From my viewpoint, I can't say what has happened but all of the above is possible.
It is possible but it may also be possible that if there is an issue with the starter relay it may have been burning out the new starter I have seen it happen many times as for the radiator if a shoddy mechanic replaced the radiator and didn't check the cause for the original radiator failing it can easily have the new one fail rather quickly so it could be this mechanic is trying to force you into having unneeded repairs done by damaging perfectly good parts (if you went to a good year wouldn't surprise me used to work for one and they tried to get me to do crap like that to people's cars I quit on the spot) but it may also be whom ever initially did the repairs on your car was lazy and just didn't do a proper diag.
There is absolutely no reason to touch a starter motor in a standard service, unfortunately sometimes things fail for no reason early (hence having warranty) but also unfortunately the can be dodgy mechanics that can do things like switch parts, or not fit new parts when they say they have
Its a different starter, yours is hidden away under his bench and he is going to sell you your own starter back. What a wanker.
It's a coincidence. **** happens!
I took my car for a standard oil change and then suddenly my starter (which is relatively new- less than a year old and working perfectly before the oil change) wouldn't even start. This was after the mechanic tried to sell me for several different parts that had all been replaced recently such as my radiator, starter and the transmission. I had to have them push my car into a parking space until I can have my dad go out and look at the car. Is there any chance they messed with the starter? If so, what could they have done?
