Ford Repair: no heat, heater hoses, radiator cap

Question
QUESTION: my 1996 mer sable heat gauge used to go almost to the top, then drop to 1/2 way had lots of heat.then went 1/3 up then down to bottom, little heat at 1/3. replaced heat sen, stad 3 times,flushed core & rad, all vents are blowing air, door seems to be ok, what is stoping the heat gauge from going up, stad is 195 seems to be opening to soon

ANSWER: i doubt the stat is the problem you've got something else going on-number one sounds like you have air in the system will need to be bled or purged out-first if your coolant was very dirty or has been overheated you may have blown or leaking headgaskets-this or air will cause same symptoms-to bleed air out-remove one of the heater hoses and fill radiator until water runs out of it-jack up front end about 12 inches-remove radiator cap and run engine about 1500 rpm with heater on until fan cycles once or twice-stay away from radiator opening coolant can shoot out and burn you-if your not familiar with how cooling system operates please have someone do it because you can blow your headgaskets and in my opinion they are questionable already.

make sure your coolant is at least 50/50 mixture and radiator cap is good-

good luck.

---------- FOLLOW-UP ----------

QUESTION:  Subject no heat...I doubt it is the head gaskets there is no leaks ,also the car is working great.  there is no air in the core. I am getting some heat when the gauge up to 1/3.also put on new water pump. are there any cencers to this,or computor link to this that may open stad to soon. thank you

Answer
nothing electronic about thermostat it is totally mechanical when the tempature reaches around 195 degrees the thermostat starts to then opens fully-letting hot water from engine flow through radiator cooler water enters engine from radiator which cools off engine then thermostat closes and cycle starts over again that's basically how it works-hot water is flowing or should be flowing through core all the time-now back to why i am suspicious about head gasket-the fact that it was going up to almost top of guage means it was overheating-you didn't say whether you had a 3.0 or 3.8-most sables had 3.8 engines which is notorious for blowing head gaskets-just because their are no external leaks doesn't mean you can't have gasket problems most head gaskets do not leak externally water usually gets pulled into combustion chamber in small amounts first and will cause every symptom you've named-unless you pulled a vacuum on the cooling system you very well could have air in it and that would be your best case scenario (less expensive) you probably have one of those two problems also if it is headgasket it will cause air to get back into system. i hope it isn't-good luck