Ruído do vento

501-25-83 Body Repairs - General Information 501-25-83 DESCRIPTION AND OPERATION Test method The test procedures given in the chapter Noise, Vibration and Harshness can also be used to diagnose wind noises. Road tests Wind noises can usually only be localized by road tests NOTE: There should always be two people present during road tests to find noises. A driver who reconstructs the situation causing the noise, and a person to carry out the checks. The following points should be taken into account for such road tests: ‡ Check that the tire pressure is correct. ‡ Remove non-standard ancillary components from the vehicle. ‡ Choose a dry, flat road with as little traffic as possible. E122761 Item Description 1 Test pipe 2 Test pipe opener 3 Puffer ball Mode of operation: The flow checking device is a set made up of a flow-testing pipe, a test pipe opener, puffer ball and closing-off caps for the pipe. The test pipe contains a filling layer which is impregnated with fuming sulfuric acid. When air is blown through the pipe by the puffer ball, sulfuric ‡ Carry out the road test in all speed ranges. Use a high gear so that the engine noise is low. ‡ Do not perform a road test near any sound reflecting objects. If it is difficult to detect the noise sources, the search can be made easier by masking potential areas. Chalk/powder test This test checks the contact surfaces of seals on doors, hatches and lids. Process using a door seal as an example: To do this, the door seal is coated with powder or brushed with chalk. A thin layer of grease is applied to the surface against which the seal makes contact. The door must then be slowly closed and reopened. The width and continuity of the imprint can now be checked on the seal. Smoke test Flow checking device acid aerosol is emitted in the form of a white smoke. NOTE: Pay attention to the instructions for use and the safety directions issued by the manufacturer. The smoke test can only be performed in a draft-free environment. This test can be used to detect leaks visually. Procedure: ‡ Break off both tips of the pipe in the pipe opener, in exceptional cases in the top of the packaging. ‡ Insert the pipe into the puffer ball so there are no leaks.