Im in the middle of a cross cpuntry trip on my 07 escape hybrid. I have 110k on the car, has ran fine since ive had it (only a few months) but i have put over 6k on her already,

Anyway like i said, car ran fine for 2 days on the trip, then out of nowhere i get a red high temp indicator light, and i pull over to check out coolant levels are fine, MECS pump seems to be running as I can hear it running and see a small flow in the tank, and it appears to have been replaced with the 'new style' pumps.

Temps have been cold in the 40's. I let the car sit overnight and next day not even 15 miles in I get the same light, so this time I feel the lower radiator hose and notice its cold, but the bypass hose is warm, and upper hose is warm so I was thinking it was the thermostat stuck closed (although thermostat was changed a few months prior by the PO, was getting emissions CEL)

This allowed me to go about 100 miles (same driving conditions) and again to my frustration the red light came on again, i pull over to let the engine cool for about an hour, and no more then a few miles i get the light again.

I bled the system by using bleeder screw over transaxle, had some air but same overheat light.

Heater works great, doesnt seem to trigger anything, and when im idle or at a stand still the car goes into electric mode with no problems.

Radiator fans kick on. Heater temp dies down quickly when car ignition is turned off (a sign that the engines water pump is working?)

No white smoke out of exhaust, a few water drops, but no steam or coolant loss or oil loss that would indicate a head gasket issue...

Im stumped.

Any help would be greatly appreciated.

Thanks.

 

Are you getting any codes?

To clarify, you replaced the thermostat?

Do you still have the disparity in the upper/lower radiator hose temps?

Coolant temp sending unit?

 

No codes, yes i did change thermostat, and on my test ride around the city the lower hose became warm, but on the highway it went cold sgain, could be because at night i am driving in 40 degree weather.

Radiator fans kick on, but when i pop the hood, i dont see traditonal signs of overheating, no pressure build up in tank, no heat, i can place my hand on the valve cover (not plastic cosmetic cover) no blasts of hot air when i open the hood.

 

I am towing a small trailer with around 500lbs in it, i dont 'feel' the weight of the trailer, and my mpg hasnt really suffered (avg 30mpg vs my regular 33) but is it possible my transaxle is gerting too hot?

Wish i had a scangauge or something i could see the perameters of whats going on thats triggering this warning light....

 

Car is willing to go to electric mode when im off highway quickly and stays in electric mode as normal, even with trailer.

Ive tried sitting at idle with the heat at full blast for 20 minutes trying to get the high engine temp light but the car keeps going in electric mode.

 

Are you using a professional grade code reader? If not, get your codes checked at O'Reilly.

 

I don't feel qualified enough to reply but due to the circumstances you are in my guess would be

MECS pump
water pump
coolant thermostat - new one defective
defective temp sensor playing tricks with the engine management system
in that order. It's possible you have two issues.

Being able to monitor your sensors in real time would be very helpful. FORSCAN on a laptop connected through your OBD2 port as you are driving could be monitored by a passenger, for example
You may consider taking it to a Ford dealer with at least one very experience FEH tech that can look it over.
What is the weight of the trailer? You have 500 pounds on it but the trailer could weigh 1000 on its own. That would put you overweight.. Ford may not have cold climate tested a 1500 lb trailer and load. The system is keeping the thermostat partially closed since ambient is so cold and you are asking for cabin heat but the transaxle is overheating. Can you buy a cheap temperature gun and take measurements of the rad, hoses, engine head and transaxle when its in an overheat condition?

Let us know what happens.

 

Naw, the trailer is a tiny harbor freight trailer, not covered only like 4ft long, u can pick it up pretty easy.

Does anyone know if the water pump shows signs of failing via a weep hole or anything?

Ya i wish i had a scangauge to read engine parameters...

I drove 170 miles today with the light only coming on once sfter 80 miles and i only waited like 20 minutes to let 'whatever' cool down. Then finished off the leg of the trip.

 

I bet bad t stat. U have to use oe. If u didnt have this happen before t stat the that where i would start.