Noah Harbinger Posted August 1, 2021 Report Share Posted August 1, 2021 On 4/7/2021 at 9:35 AM, Bill-N said: The assumption is that the Energi engine will be used about half as much as in the hybrid, hence the longer oil change interval. Which is also why the Energi transmission has a separate oil pump. Something I wonder about that separate oil pump, or lack thereof for the plain hybrid, is how long do you have to drive with the engine off (e.g a long downhill with lots of regen and EV usage) before the lack of an oil pump causes heat problems for the electric motor? Quote Link to comment Share on other sites More sharing options...
cr08 Posted August 2, 2021 Report Share Posted August 2, 2021 On 8/1/2021 at 7:13 PM, Noah Harbinger said: Something I wonder about that separate oil pump, or lack thereof for the plain hybrid, is how long do you have to drive with the engine off (e.g a long downhill with lots of regen and EV usage) before the lack of an oil pump causes heat problems for the electric motor? In theory it shouldn't be a concern in that scenario. For the Energi model, that aux trans fluid pump will be running any time the vehicle is on. For hybrid models, the battery is small enough that it will get filled very quick if you have a good enough downhill and then the ICE will kick back in for engine braking and thus the primary engine driven pump will be operating again. Quote Link to comment Share on other sites More sharing options...
SnowStorm Posted August 3, 2021 Report Share Posted August 3, 2021 On 8/1/2021 at 8:16 PM, cr08 said: For hybrid models, the battery is small enough that it will get filled very quick if you have a good enough downhill and then the ICE will kick back in for engine braking and thus the primary engine driven pump will be operating again. Engine braking doesn't happen unless you are in 'L' or have downhill assist ON. I've filled the HVB numerous times in normal 'D' mode and you then have to use friction brakes to hold down your speed. In my view, you should NEVER allow engine braking to go active since I'm very suspicious that there was some problem going out of that mode that caused my transmission failure (horrible 'clunk' and nasty sounds). I still doubt that the lack of an oil pump has anything to do with transmission failures. Apparently, Ford fixed the problem without adding one. cr08 1 Quote Link to comment Share on other sites More sharing options...
fbov Posted August 3, 2021 Report Share Posted August 3, 2021 I see C-Max engine braking as similar to a diesel's engine braking, which is commonly used enough to have "No Engine Braking" signs. Not a reliability concern, even if it's obnoxious. The Escape has a similar HVB cutoff, but it switches to what I suspect is a resistive load. Regen drops from up to 35kW to 20kW when the HVB is full. And I still go with the data that says the oil pump makes a difference in reliability. Problems can have multiple solutions. Quote Link to comment Share on other sites More sharing options...
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