2003 Jetta cooland light(red) on

[johnalwang]

Hi guys, I probably fall into a scam on a local shop(I don't want to release the brand name in case I am wrong). It was a simple oil change job for me today when I left the car to the shop, but ended up with my coolant light(red) going off with beeping and flash right after I am drive out of the shop's parking lot. Just don't believe such a coincidence happen to me.

Let's stick to the symptoms. Within half mile afterI hit on road the coolant red light went off with beeping and flashing thereafter and the temp went to the max of 260F, but it cooled off a little if I were stuck in the traffic, then went off again after I sped up. The strange thing is that while the car is idle with engine on the temp is stable on 190F, or if I stopped for traffic light the temp was also down to the normal range but well above 190F. Any idea what is going on or what kind of evidence I could collect on a foul play?

My car is a 2003 Jetta GLS 1.8T and runs for 52K miles by now and is in great condition. This thing never happened before. Thank you. This is my first post here and really furious on what they might do to me.