2014 CX-5 maybe overheating?

Hopefully someone can shed some light into what's going on. For the last couple of days we have been in a cold snap around -30C. I was driving the car and noticed that the ambient (outdoor) temperature sensor would read the proper temperature upon starting the car but, after driving for 15-20 minutes it would shoot up to +10-15C.

I took a look around the engine bay, and there is no visible signs of coolant leaks (even tho I know the temp sensor is behind the front bumper and has nothing to do with the engine temp). I noticed whenever I run the fan on the heat cycle (fresh outdoor) it would blast hot air which would almost burn my hand. Whenever driving the temperature sensor (the outdoor one not the engine temp sensor) would rise upon acceleration but whenever idle it would go back down.

I should say the dash does not light up with any of the warning lights. Turned the engine off, inspected the coolant after removing the radiator cap, and there is a bit of bubbles.. The overflow coolant container is in between full and low. I'm thinking the thermostat maybe stuck closed.. Anyone have any other suggestions what I should check.

information about the car..

2014 cx-5 2.5Gas
120,000 KM
cooling system was inspected (pressure tested by mazda last year and no issues)
 
L
GA prior 16 CX5 GT
V
20 CX5 GT + Prem
Sounds like the outside temp sensor is going bad with a higher voltage input after warm up when the voltage rises. If you think the engine is too hot and your engine temp is not showing it, throw a little water on the engine block/head, not the exhaust manifold. If it quickly turns to steam it is too hot if not it is likely OK. If you remove the radiator cap on an engine that is too hot it will boil out the coolant and possibly burn your hand as you release pressure that allows the temp to be above boiling. When you open it creating no pressure it will flash to steam and throw the coolant out on you if it is well above 212 F/100 C. A bit of burbles is OK as it is designed to run at or slightly above boiling. If your thermostat was stuck it would likely get very hot and blow the coolant out into the overflow tank...
 
Sounds like the outside temp sensor is going bad with a higher voltage input after warm up when the voltage rises. If you think the engine is too hot and your engine temp is not showing it, throw a little water on the engine block/head, not the exhaust manifold. If it quickly turns to steam it is too hot if not it is likely OK. If you remove the radiator cap on an engine that is too hot it will boil out the coolant and possibly burn your hand as you release pressure that allows the temp to be above boiling. When you open it creating no pressure it will flash to steam and throw the coolant out on you if it is well above 212 F/100 C. A bit of burbles is OK as it is designed to run at or slightly above boiling. If your thermostat was stuck it would likely get very hot and blow the coolant out into the overflow tank...
Thanks for the great information. So the outside temperature sensor does more than just tell me what the outside temperature is?
 

erhayes

Contributor
V
Mazda CX-5 FWD Touring
You are correct. They outside temperature measurement is separate from the engine coolant temp. Ed
 
L
GA prior 16 CX5 GT
V
20 CX5 GT + Prem
The outside temp likely feeds the Climate Control Auto System so it knows how to react to the temp and where to route the airflow. It also likely feeds the engine control system so it knows to inject extra fuel when real cold with dense air especially when starting and less when hot although I think there is also a temp sensor in the intake airflow...
 
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yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg. Plano, TX
Contributor
L
Plano, Texas, USA
Awesome, I will order the part, and replace it. Should be fun taking off the front bumper... o_O
The outside ambient temperature sensor is poorly located in front of radiator on CX-5. It’s easily to get affected by high radiator temperature especially when the car is not moving. If your CX-5 is a bit overheating with higher radiator temperature than usual, you may see the outside temperature display going up on temperature too.

I believe you should check if the outside temp sensor is properly affixed first as this sensor usually is very long-lived.
 
I have some UV Coolant Dye laying around, I'm going to drop it into the coolant because there is a very faint smell of burning coolant just for reassurance the rad, hoses, waterpump aren't leaking
 

yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg. Plano, TX
Contributor
L
Plano, Texas, USA
I have some UV Coolant Dye laying around, I'm going to drop it into the coolant because there is a very faint smell of burning coolant just for reassurance the rad, hoses, waterpump aren't leaking
I wouldn’t mix coolant dye with FL-22 coolant. Just check the coolant level in the reservoir. If it keeps dropping, you have leaks somewhere.
 
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