So it's been in the teens to twenties this past week or so. We've been using my girlfriend's mountaineer a lot to get to and from work. Now being its a 2003 model, it has the digital readout for temperature for heat and A/C. Yesterday I put in a automotive thermometer in the vents to see how warm they are getting. Well with the heat controls only allowing up to 90 degrees, the air coming out of the vents is about 90-100 degrees. Now when it's this cold out l, that is unacceptable.

I'm use to have blast furnace like heat from the 99 F150, where you have the ***** for heat and the temps, depending on outside air can be between, 140-150. Coolant level is perfectly fine in the vehicle. It does have front and rear climate control and even the rear vents don't get much above 100-102. Is there something wrong with the thermostat, is there anyway to get an extra 40+ degrees, or is this the normal range for these vehicles? Defrost works just fine front and rear. Just sick of freezing my butt off. Wearing a carhartt jacket and snow pants is very bulky when not needed.

This past fall, I did reset the KAM, to help fix a high idle issue, but that never fixed the problem. Did resetting that mess up the HVAC?

 

Does her Mountaineer have heated seats? You can turn those on to help warm up.

Are you using the Auto setting of the electronic climate controls, or manually setting the temperature and fan speed? If you have the fan speed too high it may be blowing air over the heater cores faster than the cores and exchange the heat to the air, try a slower fan speed.

You can also try setting the temperature to the max, but I think that is 90 degrees and probably why you mentioned that....

-Rod

 

Yes it has heated seats...well at least the passenger side is working and not the driver side no idea. One thing I did notice was the heat is sensitive to how high the fan is blowing, at least in this vehicle compared to others, in that you need it on low, just to get heat, other wise its cold air. 90 degrees is the max setting for heat, unfortunately.

 

So I did an experiment that did show results. On my way home tonight, I used the recycle air button, that you'd normally use for AC. Doing so increased the temperature from about 102 to 110 degrees. So that's helpful. Now I either have a blocked heater core, air in the lines, or a stuck thermostat. Engine gets up to temp after driving for a good 5 minutes or so.

I double checked the controls for something like a max heat, but nothing of the sort on there.

 

You should find out first how hot the engine coolant is once it has fully warmed up to normal engine temperature.

Pointing IR thermometer to the engine coolant outlet leading to radiator is one way to get a pretty good indication.
There are other ways, like for example having a proper working engine temperature gauge.

I would not trust the factory "gauge" in the instrument cluster of over 12 year old truck.

There is no way my 4.0 L would warm up to normal temp in 5 minutes of winter driving!

 

If your cooling system has not been flushed recently, pull the thermostat out, pull the radiator and heater core hoses off. Get your hose and flush the heater core, radiator and engine until water runs clean. Replace thermostat with Motorcraft brand.

Also check this out. I made this repair on my Crown Vic and this made a big difference. The AC was colder and the heater was much hotter. I think the blend door was not being properly controlled.


How to Change your EATC O-Rings | Body and Interior | Crownvic.net

I hope this helps.

George

 

Interesting. I'll be curious to know if the Explorer has vacuum lines on the EATC. I thought the whole system was electric.

-Rod

 

I'll take it in for a proper flush. Isn't the heater core behind the glove box or is it under the hood on the passenger side against the firewall? Haven't done any work since been busy with work and it's been too cold to do any vehicle repairs. Waiting for a 20 degree F day so it's decent.

 

Like I said earlier, find out if the engine is running at proper temperature before spending money on anything else!

 

It is running at its proper temp. Last few days it's been taking longer to get there due to it being sub-zero. I'll be pulling the thermostat out next week since it'll be 26* out.

 

Sorry, I don't mean to bug you but why pull the thermostat if it is running at "proper temperature"?

How hot is that in F or C?

 

According to the gauge, it's in the middle, right around 190F. I am basing a faulty thermostat based on previous experience from the past with other vehicles. Ideally I would like to floors the whole system and replace the t-stat then, but we can't have a vehicle down right now and it's too cold to run a garden hose to flush the whole system.
​

 

Replaced the t-stat and topped off with coolant, left the cap off the allow air pockets to escape, got up to 130F. Did check the heater core hoses, one was definitely hotter than the other, so when I can, it'll be getting a complete coolant flush and a new cap for the resivior.

On a completely unrelated note, check engine light popped on today with a P0308 and P0316, meaning crank position sensor dected a misfire in cylinder number 8 (driver side back plug) at 1,000 rpm under startup. Pulled the plug out and it was just slightly white on the electrode wire, but the bottom of the plug was black, so I'm reading it as a potential rich mixture. Narrowed it down to a bad coil pack or bad fuel injector.

 

Recirculate will help, because you are adding heat to the inside air, which is warmer than outside air. Do NOT run fan at high speed until coolant is hot enough.
You'll need an ODB2 bluetooth adapter and an APP to actually read coolant temp, because you can only get more heat if the coolant is hot.

 

Running the fan above level 3 gets the air too cold. 2 seems to be a good spot for now. Fan has 6 speeds I believe. We run the rear heat to help keep the temp decent.