For gasoline cars, insist on a compression test: each cylinder should read within 10-15% of the others, and the actual values should match factory specs for that engine. A single low cylinder points to worn rings or valve problems that idle checks will never reveal. A leak-down test goes further. It pressurizes each cylinder and measures how much air escapes and where. Air hissing from the oil filler cap means ring wear; from the intake or exhaust means valve issues; bubbles in the radiator coolant mean a head gasket problem. This is the single most revealing test for engine condition. Also request OBD scan data with freeze-frame records, a coolant system pressure test (to catch hidden leaks), and an inspection of the timing belt or chain condition with service history. For electric vehicles, compression tests don't apply — instead ask for a battery health report from the BMS, motor insulation readings, and a road test logging any inverter or drive-unit fault codes. A written report with photos or video of each test is essential evidence for your records.

Yes. For software crashes, a forced restart (Hard Reset) can usually be done with a specific combination of physical buttons or by disconnecting the negative terminal of the 12V battery for 5 minutes to recover. We will send you these engineering operation manuals.

Our shipping quotes are typically valid for only 7 to 14 days. If a CIF contract is signed and there are significant fluctuations in shipping costs due to war surcharges or route changes imposed by the shipping company before the vehicle is actually loaded, we will transparently provide you with the official price increase notice from the shipping company. At that point, we reserve the right to renegotiate the freight difference or allow you to change the trade terms to FOB, letting you designate your own freight forwarder for booking.