2018 Expo Max 3.4 ECO Consuming Coolant/ Code P0453

[winterkill]

My wifes daily driver with 140k miles is consuming about 1 quart of coolant every week.
Nothing dripping and no visable leaks.
No white smoke coming from the exhaust.
Where do i start???

Also is throwing a code for P0453 EVAP Syspem Pressure Sensor/Switch Circuit High. Getting a gas smell upon startup and it takes a while cranking to start.
Has anyone seen these 2 issues together?

 

[Benztech]

It's not likely these issues are related. Although you aren't seeing a coolant leak it is most likely what is happening. You can pressure test the system to check for leaks and pull the plugs to check for burning (plug and/or cylinder should be cleaner than the rest). The EVAP code would require some testing. A lot of times it is the sensor not reading correctly or the purge valve sticking. The fuel smell could be related or be on the supply side. Check for leaks first- a small amount can make the smell go a long way.

 

[Mr Big]

My wifes daily driver with 140k miles is consuming about 1 quart of coolant every week.
Nothing dripping and no visable leaks.
No white smoke coming from the exhaust.
Where do i start???

Also is throwing a code for P0453 EVAP Syspem Pressure Sensor/Switch Circuit High. Getting a gas smell upon startup and it takes a while cranking to start.
Has anyone seen these 2 issues together?

Also check the pressure cap. coolant could be going out the overflow, if the cap is bad.

 

[jwatso4]

My 2018 Max Plat was having the same issue with disappearing coolant. There were no indicators under the hood or on the pavement. The failure was found to be the upper heat hose. The metal crimp connection at the firewall have a history of leaking, but with the heat shield over the hose the coolant was being absorbed and then sitting directly over the passenger side turbo it was evaporating before any drips were noticed. When I peeled back the foil like heat shield it was bright orange on the inside.