Heater not working at idle

[xSHOESx]

The heater does work to some small degree if I turn the fan all the way down, but it chills to ice cold if cranked up. Over about 1.5k rpm the problem vanishes and the heater works fine any ideas???

[behlinla]

Usually that means the water pump is dying. Unfortunately this is a major job on the 3.5L because the pump is timing chain driven. It may take 10 hours labor to fix it.

[xSHOESx]

[QUOTE=behlinla;1720285]Usually that means the water pump is dying. Unfortunately this is a major job on the 3.5L because the pump is timing chain driven. It may take 10 hours labor to fix it.[/QUOTE

Any way to verify this is the problem that's not to much trouble? What else might it be? I am not seeing even a drop of coolant or anything like that and the level is right where it should be so its not seeping out I think. I know they don't always seep when "going" bad but still just want to check it if I can.

[sheila]

Are you hearing any "clicking/thumping" behind the dash when adjusting the temp. control?

[xSHOESx]

No thumping that I'm noticing I should mention I have the dual zone climate control.. its such a sudden change pull up to a stop and bam cold airget the rpm up just a tiny bit and it comes right back.

[behlinla]

The other test you can do is what I call the "idle" test. Warm up the car and let it idle with the climate control off. Watch the temperature gauge. If the water pump is bad, the temp will start to rise and keep rising even with the fans running. If you have a thermometer, measure the temperature of the top radiator hose leaving the pump in the V and also at the radiator. You might have to let the car idle for 10-20 minutes to see the effects.

If you can, put the cluster into ETM and watch the coolant temp value or use a scan tool. After the car has idled for 20 minutes, bring the engine up to 2000 RPM and watch the temperature carefully. Record the peak temperature you see.

Note: if the car starts overheating (gauge gets close to hot), turn the heat on full and get the revs up to 1.5-2k so the pump can cool the engine. If the engine doesn't start cooling down immediately, shut it off and open the hood to let it cool.

[xSHOESx]

Thanks for the help behlinla I ordered a bluetooth adapter that supposedly works with fords today for my Torque app... Ill perform this test this weekend and report back.

[xSHOESx]

I saw no rise in temp during the test hovered right around 186 f. It spiked by no more than 2 degrees... However I did notice when starting the car cold the temp was rising quite quickly up to 60 f. Within seconds and onward steadily is this normal?

[twiggy144]

Water pumps dont stop pumping. The coolant always recirculate. A failing water pump means it has started leaking. A bad water pump is known as such to have started leaking, and not to have stopped stop pumping. No heat is usually caused by a failed thermostat.

[behlinla]

Originally Posted by twiggy144

Water pumps dont stop pumping. The coolant always recirculate.

You must not have seen pictures of a failed vulcan water pump where the blades are completely eroded away. Pumps don't pump well when they don't have any blades left.

Originally Posted by xSHOESx

I saw no rise in temp during the test hovered right around 186 f. It spiked by no more than 2 degrees... However I did notice when starting the car cold the temp was rising quite quickly up to 60 f. Within seconds and onward steadily is this normal?

Thanks for doing the test, SHOES. That seems normal to me, so I think the water pump is okay. The sudden rise in temp is from the warmer coolant in the block reaching the temp sensor a few seconds after the engine is started.

As far as the heat, not sure what to tell you. Did you make sure the coolant bottle wasn't low? Does the coolant temp stay at 186ºF when you loose heat? Does the outdoor temperature sensor show a correct temperature when it does it? It could be some kind of electronics problem as well.

The gen 5's really don't have too many problems with the climate control other than the blend doors, so no real quick fixes come to mind. You'll have to do a little more observation and investigating.