ok still new to feh 2007 awd. When measured by sgII the engine coolant temp peaks between 143f and 158f. While warming up the instant mpg is extremely poor (14 to 18 mpg measured by scII). The new question is: What is normal? If not normal what is likely wrong ( temp sensor - thermostat)?
Thanks

 

Sounds like your thermostat is stuck open, which is common on that car.

Gary

 

Gary,
Thanks for the reply. Another question arises in trying to identify a replacement thermostat. For my 2007 feh, there appears to be 3 temperature ranges for replacement thermo stats, 180, 190/193 and 208w/sensor. Do you have any insight into this subject? I am particularly interested to know which FEHs used the 208 degree thermostat.
Thanks

 

I recommend you give your VIN to a Ford dealer and let them look up the right thermostat for your FEH. I would not use after market parts.

Gary

 

Yep, happened to me in my 06. Better stuck open than closed.

 

The 180 deg would work.
The 190 is appropriate.

Avoid the 208.

 

Thanks for the reply. It has been some time since I posed the question so alot has changed including the temperature. I changed the thermostat with the factory part for the Ford Escape Hybrid. The difference is extraordinary. The average CHT as measured in a scangaugeII is between 215 and 225 with a high around 235. MPG is consistenly above 29.0 mpg and has been as high as 31.2 mpg.

Because it is hot here in Virginia now the AC has been on much of the time and so mpg has suffered. The last tank was 29.2 mpg (combined city and highway).

A futher note, the thermostat that was previously in the cooling system looked to be an aftermarket part and did not look like the ford factory part. It also was not open when removed. The ford factory thermostat 3M4Z-8575-B for my 2007 hybrid retails for about $65. I replaced the thermostat myself.

Thanks again for your reply.