Here are the recent answer to this question.
By Mary (Guest Post)12/20/2008
My husband had the same problem with our 93 Ranger. Several years ago, after driving for 2 Chicago winters with no heat (he tried all the usual stuff), I suggested he SOAK the heater core in CLR over night. Then he flushed it SEVERAL times with clear water, reinstalled it and it still works fine! He is toasty warm...of course NOW the Air Conditioner does not work...but his window does!
By Steve (Guest Post)12/03/2008
I have the same problem with my 93 Ranger. Did the core flushing and all new coolent, but the temp gauge still does not climb to where it should be. Don't think there is any air trap in anywhere. Had put a new t-stat in about 3/4 of a year ago, so it should still be good, Right? Starting to get cold up here, so heat would be nice. Any ideas where to look next?
By Harry (Guest Post)12/01/2008
You could check for a broken head gasket. Check the oil on the dip stick and see if there is any water mixing with the oil. Or take it to your mechanic and he will check the oil.
Sounds remotely like a possible plugged heater core, to flush take both heater hoses off and flush with a garden hose.
Add your voice to the conversation. Click here to answer this question.