1995 Mercury Mystique Maintains heat until driving any dist

Hello,

I recently had a coolant hose blow off while on the highway and so had a pressure test done on the car to check for any cracked gaskets etc.

Mechanic confirmed no cracked issues, replaced the hose and put in 2 bottles of coolant.

Since I have had the car back I have noticed the following:

* If I turn on the car and allow it to run in park, the tempurature reached the middle of the heat gague and stays there. (Good!)

* If I drive the car at highway speed, the tempurature remains at the middle or slightly higher. (Good!)

* If I drive the car at highway speed for any distance and then slow down to stop and go traffic (street/congested road etc.), Then the temperature rapidly increases (1-3 minutes) until it is near the red line. (Problem!)
I have not tested whether or not it will continue into the red line as I turn the car off before that occurs.

I am also noticing a small grinding squeak to the engine that I never noticed before.

Finally -- prior to the overheating on the highway, in order to avoid an accident, I slid my car into some curbing (driver side front wheel followed by rear wheel) to slow down my momentum enough to prevent hitting a car. I bent a rim, and from that day forward the engine has not been acting 100% (Had a tune up done, but still had some temp problems and engine rumbling at stops/in low gear)

I am unsure as to what could be happening.

Thanks in advance