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  1. #1
    Junior Member
    Join Date
    Oct 2006

    FEH Ice Coolant Pump

    Hi All

    Many FEH/MMH owners thought the primary engine coolant pump was electrical, but this doesnít appear to be the case. The primary coolant pump is a mechanical pump with a pulley and is driven by the accessory drive belt above the A/C compressor (Vol 1 Engine Cooling - Escape Hybrid page 303-03B-21). There is a diagram on that page also.

    The Aux. Coolant Pump (heater pump) can be seen through some vent holes near the bottom of the radiator shroud (drivers side). The larger coolant pump for the electronics is just to the right (passenger side). Another diagram of the aux. pump is on the next page (22) in the repair manual above. This pump is only activated while in EV mode with the climate control switch in any other position but OFF. Coolant still circulates through the heater core while the engine is running and I got that wrong. Someone at GH was thinking about adding an ON and OFF button for the Aux pump, but that would not do much more than stop circulation of coolant while in EV. You can do that by turning the climate control switch to the OFF position.

    It appears there is a by-pass hose from the mechanical coolant pump to allow circulation of coolant through the engine until the thermostat opens to allow radiator flow. This all means that the volume of coolant will not heat any quicker with the heater pump OFF. However, if the climate control switch is in any position but OFF while in EV going down a mountain, you could cool down the engine for a restart of the ICE in cold weather. The most that could be gained with this information is how to save energy (electric motor running) and engine heat while in EV. This will improve MPG and further explains my increase in mileage since I stopped leaving the climate control switch in the vent position and just turn the thing off.

    Havenít found anything that states the PCM would kick on the Aux. Electric Pump if the primary mechanical pump failed or the drive belt broke. It may mean the Aux Pump is to small for cooling the engine.


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  3. #2

    Your right in most cases

    Your right in most cases there is a by-pass hose from the mechanical coolant pump to allow circulation until the thermostat opens to allow radiators flow.

  4. #3

    Gary, I'm glad to find this

    Gary, I'm glad to find this even though it was posted quite awhile ago. Last spring we bought a MMH AWD which we really like. Getting close to 30 mpg overall in mixed suburban driving.
    Being used to heavier vehicles and towing (not with this little guy....) I am aware that you need to let things cool off gradually after running for awhile. My concern is when pulling off the hwy, the ICE shuts off when you get below the magic 44 mph. WIth the mechanical cooling pump now off as well, there is no coolant flow to the hot spots in the ICE.
    The service mgr. at my otherwise very knowledgable dealer - whom I like a lot - didn't really know anything about it. He did tell me that in five years of servicing them, he hasn't seen any issues with head gaskets, manifold gaskets, and so on.
    I am wondering if the engineers took this into consideration when they designed the systems around the Atkinson ICE. I would guess not, because that would cost more to manufacture, but I do wonder if this something I should be concerned about.
    Any light you can shed woudl be greatly appreciated.

  5. #4
    Junior Member
    Join Date
    Oct 2006

    I'm not concerned at all

    I'm not concerned at all about hot spots and I've never heard of any problems in 5 years. In fact, Ford is going to design the next non-hybrid vehicles with start/stop technology so just about all Ford vehicles will shut-off while slowing to a stop. The engines will automatically restart when the gas pedal is reapplied.

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