Car overheating??
l have a 96 Mercury Sable. The car is overheating and radiator resivior is gurgling. And there the heat in the car is blowing only cold air. We changed the thermostat and it did not help?? the antifreeze was leaking of out of the resivior but that is the only place it was leaking. so far it is not leaking any more at all. l was told by some one it might just have air bubbles in it and it could be causing pockets of air therefor the anitfreeze can not get to the engine ?? and we should try to get the air out? but what does that have to do with the heat coming out cold? also we can not find the radiator cap?just the resivior cap

Maybe it is the Heater Coil?

temperature control goes to a valve some are direct linkage some operate off of vacuum but whatever yours is it is either plugged up or not operating (opening)
Water should not be bubbling out of reservoir either that is usually the sign of a blown or leaky head gasket. If you recently added some fluid you may have overfilled if it has stop bubbling by now.

OK if your car is overheating you have a cooling system problem, no heat inside means the hot water is no reach the heater core or a close valve or something, or the water pump could be bad.Last thing thermostat you have to know it is working do not Never think that you can not buy something bad. (Not going with the air bubble theory hope this helps.)

thermostat

try changing your thermostat.

the thermostat regulates the water temp that goes through the car. when it goes, you have no heat.

it is located in the hose that leads from the radiator to the engine-it is on the engine side.

it only costs a few bucks and is easy to replace.

Could be just air bubbles. The cooling system is what goes through ur heater core to produce the heat also in the car which is why u have no heat if there is bubbles or if the fluid is too low, or possibly there is a clog at the heater core as well. But. .if u do not have a cap on the radiator, the system can not create pressure & heat properly either. Go to Wal-Mart, get a new cap, start the engine & let it run with the cap off for a couple of minutes to get bubbles out & while it is running, add any fluid that u might be low. This fills the system without creating the possible air bubbles. Put the cap on & see if that helps any.

l am thinking that the water pump is done. When it is not working the hot coolant stays in your engine and overheats and the heater core does not get any warm coolant to put heat inside your vehicle. This also will happen if the belt is gone or slipping.

you probably have a blown head gasket, symptoms,

can not keep water in it, white vapor out the tailpipe

You can try some water glass, block sealer

or repair and replace