Well my car is having another cooling problem. Last night I took my car for a drive and the add coolant light came on (it's been 2 weeks since it last did) the system has been flushed and now I just put in a new thermostat and put in some coolant sealer in to try and seal the leak.. I did notice that my fresh coolant has some witch foam like stuff in it...what is it? And another thing after that I ran the car for a good 15 minutes and the heat gauge didn’t move at all is this normal with a new thermostat?

 

stop leak is not reccomended. you should flush your system and repair the leak.
the foam in your coolant may be you stop leak or it could be oil.
if your stock gauage is working properly it should move befor 15 min. i would have it inspected by a mechanic. you do not want to over heat it

 

The add coolant light can come on for 2 reasons:
1) Leaking internal or external
2) Air bubbles in system

The car can overheat because of:
1) Gunky radiator needs cleaning out
2) Someone used mineral / tapwater and the minerals have now corroded & clogged the radiator. Your autoparts store should have a soaking/flushing kit that can clear this out. I've used some mineral disolving solution before that won't hurt plastic or metal, but will disolve mineral deposits.
3) Waterpump failure
4) Ran out of coolant & engine overheated

If you've blone a coolant seal in the engine, you'll see:
1) Air bubbles in the radiator, overflow bottle running over, overheating due to over-pressurized coolant system (ie compression is leaking into the coolant system).
2) Colored exhaust or sweet smelling exhaust
3) Foamy coolant

I BELIEVE (someone correct me) a coolant system pressure test can confirm if it's a coolant seal. Most mechanics can also detect coolant in the exhaust with a sniffer machine.