Is this a problem? Overcooling but not the Thermostat.

[Falcon1772]

Took the car to a restaurant about a week ago. 30 ish degrees outside. Car didn't wanna warm up completely so it was a cold drive. Coolant temps would drop anytime we came to a stop. 
Replaced the thermostat and O=ring with an OEM ones. Same issue. 
Replaced the Coolant temp sensor. Same issue. 
Car will warm up to about the 2nd line up if I just let it idle and thats about 145 degrees-ish And then it will shut off and go into EV mode. I cannot recall if its always done this...

Got the old T stat out since this is really weird and checked it in a pot on the stove and it opened at 180, so it was fine all along.
Tried doing the bleed procedure thing with holding the pedals and whatnot that didnt seem to change much.
Checked the water pump fuse. it was good. I assume the pump is fine or I'd be overheating.

So what the heck. is this normal behavior that I've somehow just now tuned into after 2 years of ownership??  I guess my current plan is to just drive it like normal and see if it becomes a bigger issue as we get into the teens and then into the negatives. I live in Alaska so that will be soon. 

oh and this is a 2014 C-max Hybrid SEL

 

[cr08]

30 degrees F? This is normal behavior especially at lower temps like this and will be exacerbated the higher you have the cabin temp set. These vehicles don't push to get the coolant temp up to the 200-210 temp normally seen on ICE only vehicles. It only brings the coolant temp up to what's needed for cabin heat and will let the ICE cycle accordingly thereafter. In my firsthand experience I've often had it not get off the first notch on the coolant temp gauge when it gets down below freezing out when there's a ton of stop and go driving.

 

But you should be getting heat if the temp gauge is up at least off the bottom of the gauge and it has been able to enter EV operation. If it's dead cold coming out of the vents, you may want to pull codes (with a proper scanner like Forscan with an appropriate adapter with MS-CAN support, not a generic off the shelf scanner) and see if any are reported for stuff like malfunctioning HVAC dampers or if it is seeing an issue with the engine cooling side of things. These vehicles are smart and track a lot of data points for this stuff and will store codes appropriately if something isn't behaving right.

Edited September 29, 2023 by cr08

[Falcon1772]

yeah man I'm starting to wonder if I just really never paid enough attention before. I normally have heat coming out the vents by the time I pass a church on my normal route. and thats how it is now. I'm really wondering if we somehow were mostly on EV when I went to that restaurant as its only about 3-4 miles away, not one we normally go to and is a route that does'nt go above 45mph. Maybe I'm just a tard and thats all it was and that made me monitor everything way too much. lol Not sure. But the last couple trips its seemed fine. Will keep updated. 
 

Edited September 29, 2023 by Falcon1772

[ptjones]

On 9/29/2023 at 2:38 PM, Falcon1772 said:

yeah man I'm starting to wonder if I just really never paid enough attention before. I normally have heat coming out the vents by the time I pass a church on my normal route. and thats how it is now. I'm really wondering if we somehow were mostly on EV when I went to that restaurant as its only about 3-4 miles away, not one we normally go to and is a route that does'nt go above 45mph. Maybe I'm just a tard and thats all it was and that made me monitor everything way too much. lol Not sure. But the last couple trips its seemed fine. Will keep updated. 
 

Grill Covers solve this problem and Ideal WT is 210-220*F for the best gas mileage.

 

Paul

 

[Lacienega]

On 9/29/2023 at 12:27 PM, ptjones said:

Grill Covers solve this problem and Ideal WT is 210-220*F for the best gas mileage.

 

Paul

 

I don't think grill covers will do anything. The thermostat will not even open the cycle to the radiator before the temperature gets too hot. Besides, there are automatic grill shutters behind the grill that should be closed anyways in this low temps. Cars get smarter all the time ?

[jestevens]

All I can say is that a) I got into an accident, grazed the right front end and STILL had to pay for new vent shutters -- although they are only active at like 65-70MPH and up -- and b) my car NORMALLY will keep the cabin fan off in the winter until the engine warms up to the point where it can generate heat in the cabin .. unless you are overriding that by pressing the DEFROST button ..

You'd think they'd also close the shutters when the engine is very cold but I guess there's a lot more holes in the front end to "breathe through" beyond that anyway.

I don't know if C-MAX uses the same design but I know the amount of trouble the Prius goes through -- like keeping a "thermos reserve" of previously warm coolant and allowing that to loop back into the engine on demand to warm up a cool engine quicker, plus all the things it does to maintain a proper EVAP cycle are a bit crazy.

I've always averaged about 40-42MPG -- except on trips around town it does more EV+ and a few times gets 50+ MPG. Lately the dealer installed the "wrong" tires which are stickier and hard to pulse and glide .. I assume they'll wear down to 7/10's eventually anyway and for now enjoying more burn out potential. Edited October 1, 2023 by jestevens

[Falcon1772]

Ok driven it a few more times. idk still seems like its just running cooler and/or cooling off faster than I remember. Its not a problem persay and again, maybe I'm just being hypervigilant on watching the temp gauge now, but idk, just feels off. 
I put on my winter front today. We'll see how it goes after a few drives with it on. 

[cr08]

I'll say that as long as it's not throwing any codes, it should be fine. These vehicles track a LOT of data points and are pretty picky about emissions related stuff (of which coolant temp will be part of that). But take my info with a grain of salt of course.

 

If you want to do some reading, Ford's got an extensive document about the OBD/emissions related systems including relevant trouble codes and conditions: https://www.fordtechservice.dealerconnection.com/vdirs/diagnostics/pdf/OBDSM1303_HEV.pdf

[Falcon1772]

I think it must've just been a fluke short drive that got me all worked up over nothing. Car seems fine. Figured I'd update so there was some sort of conclusion. 

[ptjones]

On 9/28/2023 at 11:33 PM, Falcon1772 said:

Took the car to a restaurant about a week ago. 30 ish degrees outside. Car didn't wanna warm up completely so it was a cold drive. Coolant temps would drop anytime we came to a stop. 
Replaced the thermostat and O=ring with an OEM ones. Same issue. 
Replaced the Coolant temp sensor. Same issue. 
Car will warm up to about the 2nd line up if I just let it idle and thats about 145 degrees-ish And then it will shut off and go into EV mode. I cannot recall if its always done this...

Got the old T stat out since this is really weird and checked it in a pot on the stove and it opened at 180, so it was fine all along.
Tried doing the bleed procedure thing with holding the pedals and whatnot that didnt seem to change much.
Checked the water pump fuse. it was good. I assume the pump is fine or I'd be overheating.

So what the heck. is this normal behavior that I've somehow just now tuned into after 2 years of ownership??  I guess my current plan is to just drive it like normal and see if it becomes a bigger issue as we get into the teens and then into the negatives. I live in Alaska so that will be soon. 

oh and this is a 2014 C-max Hybrid SEL

 

You need a ScanGaugeII or similar gauge to get an accurate reading and put Grill Covers to solve the problem.  Look up the thread up on Grill Covers, it worth 2 to 4 mpg.

 

Paul