Over heating car changed thermostat,acting really weird?

one day my heat quit working in my (95 taurus 3.8)so i got on the free way and it started blowing luke warm then 10 min later it was blowing hot as soon as i got off the freeway it started blowing cold instantly,i took it to a shop and had the thermostat replaced,he even took the hoses off the heater core and blow it out,and still the same ,after leaving the shop it was getting really close to over heating so i made it home waited 2 hours and left my house againgot on the freeway(yes dumb)and it started over heating this time the gauge was reading that it was over heating but the car sounded normal and ran normel,but i pulled over anyway and turned the car off and i could hear bubbleing coming from the resivor,got back home safe the next day got in my car and drove it around all day and it was fine,but iam afraid that it will overheat again,what could be causeing it to act like this?
Over heating car changed thermostat,acting really weird?
there my be air still in the system
Over heating car changed thermostat,acting really weird?
Most of these cars have an electric fan that helps keep the engine cool, check to see if its functioning properly.
It could be a bad thermostat, or one rated higher than what your car is made for. Usually 180 deg is safe. You could have air in the system, check this by starting the car cold and taking the radiator cap off and let it run for a few minutes. Keep an eye on your coolant level, if it goes down, add anti-freeze. After about 5-7 minutes and your coolant level looks good, replace the cap %26amp; check your resevoir %26amp; make sure it is up to the warm/hot line. After it is %26amp; the system is closed back up, shut the car off for 5 minutes. Then start the car %26amp; take it for a drive, this should've taken care of the problem. If it doesn't, you might want to have you water pump checked out. Good luck.
I had a similar issue in my F150 p/u. Turned out to be two things...a vacuum check valve and a %26quot;tired%26quot; diaphram on an airflow gate (door) under the dash. replaced them and now they work like new!
If you want to be on the safe side, take it to a different mechanic (a competent, conscientious one) and have him replace the Thermostat again, with a high quality brand, and have him check the fan too. Make sure there is heat coming out of the heater, and the temperature is stable before you leave the parking lot.