Experience turbo lag and power surge during road tests; check for significant oil accumulation at the turbo intake and intercooler connections (slight oil vapor is normal); and use OBD to read the real-time boost pressure peak to see if it meets factory settings.

Odors are difficult to convey through images, so our quality inspectors conduct subjective smell assessments and record them. For vehicles with severe smoke or mold odors, if deep ozone sterilization is ineffective, we will downgrade the vehicle and mark the report with a red "Odor Warning" at the top.

As rubber seals age, "slight oil seepage (oil stains but no dripping)" is very common in used cars and is not considered a major fault. Our recommendation is: as long as the oil level does not drop abnormally, just clean and monitor it regularly after arrival, without the need to immediately incur high costs to disassemble and replace the seals.