看汽车零部件防护表层是否完好。大多数零件在出厂时，都涂有防护层。如活塞销、轴瓦用石蜡保护；活塞环、缸套表面涂防锈油，并用包装纸包裹；气门、活塞等浸防锈油后，用塑料袋封装。选购时若发现密封套破损、包装纸丢失、防锈油或石蜡流失，应予退换。
See if the surface of the auto parts is in good condition. Most parts are coated with protective layers when they are out of the factory. For example, the piston pin and axle bush are protected by paraffin wax. The surface of piston ring and cylinder liner is coated with rust proof oil and wrapped with wrapping paper. After the antirust oil such as valve and piston is packed, it is packed in plastic bags. If the sealing sleeve is damaged, the wrapping paper is lost, the antirust oil or the paraffin wax is lost, it should be replaced.
看胶接零件有无松动。由两个或两个以上零件组合成的汽车零部件，它们之间是通过压装、胶接或焊接的，不允许有松动现象，如油泵柱塞与调节臂，是通过压装组合的；离合器从动轮与钢片是铆接结合的，摩擦片与钢片是铆接或胶接的；纸质滤清器滤芯骨架与滤纸，是胶接而成的；电器设备的线头是焊接而成的。选购时若发现有松动，应予调换。
See whether the adhesive parts are loose. By two or more than two parts combined into auto parts, among them by pressing, bonding or welding, does not allow loosening, such as pump plunger and the adjusting arm, by pressing the combination; clutch driven wheel and a steel sheet is riveted with the friction plate and the steel plate is riveting or adhesive; the paper filter frame and filter is glued together; electrical equipment is formed by welding wire. When it is found to be loose, change should be given.
看转动的汽车零部件是否灵活。选购转动部件总成时，用手转动泵轴，应感到灵活无卡滞；选购滚动轴承时，一手支撑轴承内环，另一手打转外环，外环应能快速自如转动，然后逐渐停转。若转动部件转动不灵，说明内部锈蚀或产生变形，不要购买。
See if the rotating parts of the car are flexible. When you select the rotary assembly, you should feel the flexibility of the pump shaft when you rotate the pump shaft with your hands. When you choose the rolling bearings, you need to support the inner ring of the bearing with one hand and rotate the outer ring with the other hand, and the outer ring can rotate quickly and then stop gradually. If the rotating part does not rotate, it indicates the internal rust or deformation, do not purchase.
看总成部件有无缺件。正规的总成部件必须齐全完好，才能保证顺利装配和正常运行。一些总成部件上的个别小零件若漏装，将使总成部件无法工作，甚至报废。
See whether there is a missing piece in the assembly. The regular assembly must be complete in order to ensure the smooth assembly and normal operation. If a few small parts on the assembly parts are leaked, the assembly will not work or even be scrapped.