Mondeo Engine Smoke and Power Loss

Smoke is never a good sign! I'm skeptical it's just the crankcase ventilation. A bad valve could cause pressure issues and maybe some oil to get burned, but smoke usually points to something more serious. Is it bluish smoke, which would mean burning oil from worn piston rings or valve seals? Have you checked your oil level lately? Is it dropping faster than usual?

The smoke does have a bluish tinge, so it could be burning oil. I've been watching the oil level, and it has decreased slightly over the past few weeks. Could a bad crankcase ventilation valve make oil consumption this bad, or is it more likely piston ring or valve seal wear?

Okay, the bluish smoke and oil consumption point away from just a crankcase ventilation problem. Think of the ventilation system as a band-aid; if the engine is already burning oil due to wear (like worn rings), the ventilation system might struggle to keep up, making the problem more noticeable. It sounds like your engine has multiple things going on. I advise taking it to a trusted mechanic for a proper diagnosis. They can do a compression test and leak-down test to check the health of your piston rings and valves.

Based on your assessment, I scheduled a diagnostic evaluation with a technician. It was a defective crankcase ventilation which caused increased pressure and led to smoke when accelerating, plus worn valve seals, so I had both fixed for 360€.