Last week I noticed that several times throughout the week, whenever I'm stopped at a light and place the transmission on Neutral (while the A/C is on), the idle increases drastically and drops and races again. Since this 2014 Ford C-Max Hybrid does not have a tachometer, I am guessing that it is possibly goes up to 3,000RPM on its own. Several days after while on the Freeway I heard a noise coming from the front of the car, which sounds like a metal bolt twirling around and around. A few seconds later, antifreeze suddenly burst from the hood of the car and I decided to make an emergency exit. After I opened the hood I noticed that the plastic coolant reservoir expanded and there's a hole on the front side it (see attached picture)? I'm not sure why did it build up so much pressure on the reservoir like that and blew a hole on the plastic, and why didn't the reservoir cap relieve some of the pressure?
After I replaced the coolant reservoir with a new one, I filled it with orange antifreeze for North American cars. After installing the new part, I started the engine, and the engine's idle was erratic. It races up and down throughout the 5 minutes that I had the motor running. There are No white smoke nor any other colored smoke coming out of the tail pipe. I didn't see any message on the dashboard other than an orange lit up engine icon.
If this scenario has ever happened to you, please Advise what you did to fix this problem. Thank you!
Pls. See attached pictures.
