Heating problems

I have a '97 Ford Taurus. At low rpm's I have little or no heat. At 1500 and above, heat works fine. I have flushed the cooling system,flushed the heater core twice,both directions. Took it to a repair shop,tech said it was the blend door. He replaced it twice and still the same. I have pinched off the bypass line and it seemed to improve a little. Could this be a water pump problem? I have no leaks,no lose of coolant and the engine runs at normal temp.

go to taurusclub.com re cooling system

Thank you

As an old wrench, I would have never guessed that a water pump would fail to pump, but it happened on my 98 Taurus.

I had some leakage from rotted out heater core piping along the firewall. No parts were available so I bypassed the heater core with a length of heater hose and just refilled the cooling system with water. It was summertime and I wasn't worried about not having antifreeze in the engine. The new parts came but I still didn't get around to the job for about 2 months.

When I drained the water to replace the piping I was horrified to see the clay-red water that glugged out. This had been a clean cooling system and now was rusty as hell. After filling and pressure testing, all was fine except I noticed that the temp guage would fluctuate a little from normal to a little above normal (while sitting at stop lights). When I began driving again, the needle returned to normal. I assumed the thermostat had gotten a little fried and finally was giving out.

Replaced the thermostate, but same thing. The weather turned colder and I realized no heat at idle (blows cooler and cooler, then cold). Start driving and heater air warms again. Good heat on highway...just cold at idle.

Think about it. Once the engine warms from cold and the temp is around normal, I only get heat when driving (or sitting stopped and revving the engine above idle, 1500 - 2000 rpm). Also, the engine starts overheating while sitting. Feels freaky to watch the temp guage climb while the heater blows colder air. If I didn't know better, I'd say the water pump isn't pumping.

Just for grins I took it to Goodyear (where I happen to know they have some pretty good all-around guys). They tried flushing and stuff but no change. Finally, I decided it had to be - so pulled off the water pump. I'll be damned if all the impeller fin metal hadn't completely rotted off! I installed a new pump and I've been warm and toasty ever since (and no more creep-up on the temp guage). I had never seen a water pump impeller rusted away like that before. For me, it happened because I ran straight water in the system for 2 months. Pretty stupid stunt for an old wrench.