2017 Mercedes-Benz GLC 300 (W253, M274, 9G-Tronic) arrived with mixed oil-and-water-like residue beneath the parked vehicle; the evidence, repair and bounded verification are documented here.
A 2017 Mercedes GLC300 lost acceleration at highway speed and stored P029921. A vacuum hold comparison exposed the leaking turbo actuator before replacement restored reported power.
A 120,000-km Mercedes E300 stored P06DA00 and kept its engine warning lamp on. Oil found at the oil-pump control solenoid connector led to solenoid and anti-siphon lead replacement, terminal cleaning, oil-pan resealing, and a successful initial code-and-warning recheck.