I have a 1995 Mercury Sable. I have replaced the water pump, the thermostat and flushed the cooling system twice. I have gone through every method I could find to eliminate possible air locks. Only once did the system operate correctly and that was during the cleanup right after a flush. The temp guage was reading about center and the heater was blowing heat extremely well. After draning the system and refilling with 50/50 it went back to the temp guage reading low (barely moving up at all) and the heater/defroster blowing hardly any heat at all. There are no leaks anywhere. What could be causing this problem of no (little) heat?
This problem probably dates back to the original water pump problem. You likely got it a little too hot and now have head gasket damage that is pumping combustion gas into the cooling system. You can have it chemical tested to find out.
June, 26, 2011 AT 1:55 PM
I deal mainly with ancient vehicles
To get you prepped and ready for a better diagnoses, from another. Sure To Jump in!
And to accelerate your fix. More info may be needed
Let's get it out of the way now, so we can get you warmed up sooner!
Are your heater core inlet and outlet hoses nearly as hot as the upper radiator hose when your vehicle is at normal operating temperature, when you are having the "No Heat" issue?
With my Jeep, I went thru 3 thermostats once, before I got one that worked. So even new stuff can be bad too!
June, 26, 2011 AT 2:36 PM
To the first reply, the car still runs like a top. There has never been an issue of over heating. This all started with a pin hole leak in the top of the radiator, which was repaired.
To the second reply, all hoses have basicly the same temp to them. I am going to replace the thermostat again today and hope thats it. It just seems the temp is running with a stuck open thermostat much like I have just removed it and am running with out one at all. Which I did do to an older vehicle eons ago when I was much younger.
June, 26, 2011 AT 2:45 PM
If temp of hoses is the same. Hot!
Maybe you have a Door issue in the heater box?
June, 26, 2011 AT 2:57 PM
I have thought about that but I wonder why it worked that once. Also I haven't looked that up (the door issue) but doesn't that mean disconnecting the dash and pulling it back? Also I thought about it and when the temp guage runs at about half (center) then the heater/defroster operate correctly, blowing plenty of heat. When the guage runs low, hardly any heat is blowing out.
June, 26, 2011 AT 2:59 PM
I think this is you, at the reference (I'm rusty with) Both Manual and Auto HVAC systems were mentioned.
This is the only exploded view I was able to find
Maybe it will aid you
June, 26, 2011 AT 3:15 PM
I might also say that yesterday I was upside down looking under the dash on the passenger side and when I reached up to adjust the control from a/c clear around to defrost, each time I moved it I saw the (acuator arm?) Move in or out depending upon which way I turned it. While I did that several times and it always moved, I could not see what it was moving or if it was moving it all the way.
June, 26, 2011 AT 3:36 PM
I'm sorry, I know little about you vehicle
I can follow requests well, if I am able
The Manual and Auto systems could play a part as well. Maybe a sensor or something will not allow the door to open till its hot. Maybe not!
I'm used to simple, cable operated stuff, where diagnosis could be done by the "mentally challenged" (like me!)
A big hand mirror and a bright flashlight might aid with the under dash adventures. Works well w/ my 2 Jeeps. Takes a bit of trial and error, till you get used to the reversage!
Wrenchtech, may be better with the Repair Resources and understand the other possibilities with this Newfangled stuff
Not trying to sluff you off. But that's as far as I dare tread into unknown territory, without a "Ranger Buddy" by my side.
If he is stumped, maybe others will jump in, who know your system, and aid you more. They are good about doing that!
June, 26, 2011 AT 4:18 PM
What could be causing this problem of no (little) heat?
Check if it has heater control valve
June, 26, 2011 AT 4:20 PM
Thanks, I just got the new thermostat and gonna try it.