Winter has arrived with a vengence here in Nebraska and we were at -9 wind chill this morning. When the temps outdoors started to drop last week, I was reintroduced to an issue with the Excursion that I forgot about enjoying the pleaseure of last winter...low heat supply while blasing it on high. Last winter I placed a grill cover on the Ex in hopes of holding in more heat, therefore increasing effectiveness of the cabin heater, but no such luck, it had no noticable effect. The vents still only blew luke warm air, and the engine water temp gauge never rose but a hair off the lowest mark of the "normal range" of the gauge. The same conditions exist this season; low engine heat, luke warm air, engine temp needle sitting low.

Last night I realized that earlier in the year I had bought a digital thermometer with its temperature sensor at the end of a 36" lead (meant to monitor temps in a walk-in cooler/freezer), and the ablility to record the Hi/Lo temp it read. I decided to pull an experiment this morning, record some data, and compare the Excursion data to other vehicles at my disposal at work. So here is what I have, let me know what you think.


All tested vehicles had the temp probe inserted fulling into a central dash vent, and were operated/measured under the following conditions for the duration of 25+ minutes: High heat, High fan, Dash-only vents selected (no vent blending)

2000 Excursion, 6.8L V10
Engine temp gauge reached lowest end of "normal range"
Max Dash temp. 106.7 degrees during city driving
Max Dash temp. 108.1 degrees during hiway driving
(this only feels luke-warm, being only a few degrees above body temperature)
Max Overhead/Rear temp. was only a miniscule difference from the dash temperatures

2007 Ford E-150 cargo van, 5.7L V8
Engine temp gauge reached middle of "normal range"
Max temp. 149.3 degrees during city driving
Max temp. 159.9 degrees during hiway driving

2006 Ford E-250 cargo van, 5.7L V8
Engine temp gauge reached middle of "normal range"
Max temp. 142.7 degrees during city driving
Max temp. 156.6 degrees during hiway driving

So here is my thought. It seems to be that the low vent heat in the Excursion is attributed to the low engine heat, and not resulting from a plugged Heater Core. I'm coming to this conclusion becasue the rear/overhead heater is putting out the same temperatures and not warmer temps. I'm also thinking this could all be caused by a faulty thermostat in the engine, being stuck more open than it should be.
Considering what is known, what do you think???

If it stays this cold much longer, I'm going to be a teeny bit jealous of this guy ------------>

 

Get a code reader and read the coolant temps. It sounds like a faulty thermostat ?
When mine failed it also was stuck open and the engine never got up to full temperature as it should have. Easy and cheap fix that I would do first if I was you.

 

I was going to say the same thing. You need to see what the real coolant temps are first. Could be a thermostat or maybe a bad fan clutch? I have an auto enginuity that shows me oil temps and coolant temps. You don't need to go to that expense to see the coolant temps.

I have a 2003 6.0l diesel and it was -5 here in Colorado this morning and I was getting good heat from the vents.

Regardless of the low outside temps, if the car is running properly, it should reach normal operating temperatures.

 

Do you think I could get a faily accurate reading of the coolant temperature by using a Infrared Laser Thermometer and reading the temp of the upper radiator hose after a drive while the engine is still running?

If my needle is pegging the cool end of the gauge, I already think I'm not making temperature. Either way...what should the temp of the coolant be at of everthing is operating properly?

 

Replace the thermostat, its cheap and easy and with your symptoms that is almost 100% what the problem is. Just make sure you use a motorcraft stat as people have had lots of problems with the aftermarket stuff. Just ask Brent..

 

Is Ford the only source for Motorcraft, or can they be bought at auto parts stores?
We have NAPA, Advance Auto, Auto Zone, and O'Reilly here in Nebraska. I'd prefer to stay away from a ford dealer parts counter because we all know they usually cost 2-3x as much as anywhere else.

 

For me, Amazon is a great source for Motorcraft (with Amazon prime I don't pay for shipping) or you could try Rock Auto. NAPA I know doesn't carry any other brands. You might get lucky at O'Reilly.

 

O'reilly sells it here.

 

Had a similar problem with the low heat issue years ago. Installed a new T-stat and it solved the problem. The temp gauge in the V10 Ex is almost worthless. It always runs at the very low end of the normal range, but it did move up a tiny bit after the new t-stat was installed.

 

Got mine from O'Reilly - motorcraft. My heater will melt your feet. I can keep it on full hot and on the floor it I'm serious it will burn your feet.

 

I stopped in at O'Reilly to see if they had the tstat, they only order it in and don't stock them in our store. I also found out that they come in two flavors. I have the option of a 170 or 190 degree stat, they claimed the 190 is the OEM temperature. So I'm thinking I should have them bring in the 190 to keep as much heat in there and available as possible. Agreed?

 

Yes you want the 190 OEM stat not the 170