So I'm driving yesterday evening (on the frwy) with the AC when i notice that the air isn't coming out as cold. I then notice that the temp gauge is about 3/4 of the way up so I immediately pull over. I tow the car home and this morning i filled up the radiator and reservoir tank, turn the car on and the engine is shaking like crazy.. The check engine light is on and I'm wondering if the head gasket blew?

 

Getting the code read would be a good clue for where to start.

 

a parts store can ck the codes for you free (except Ca residents)
could be a coil misfire but removing a spark plug will be the first indicator of whats really happening

usually takes more than a single 3/4 temp event to blow a gasket, but there could be a long term prob that finally showed on guage
water pump and radiator are the first suspects
Any contamination of the engine oil with coolant?

you can pressure test the cooling system to look for leak from hose or the pumps `weep hole` on bottem

driver side fan: operates off and on when driving or stopped at light a long time?
or runs for 5+ minutes after engine shutdown = bad fan temp sensor not running fan when needed
Passenger side fan operates with AC on?

 

condition of rad cap seal?