Mercedes-Benz engine abnormal sound fault

Troubleshooting: in order to verify the failure symptoms, namely engine test, in the idle state, abnormal noise is small, it is unlikely to catch, but in idle status air conditioning switch to ON, and instantly "zoom, zoom, zoom" sound of the belt slipping. Air conditioning compressor belt slipping is the reason for abnormal sound of engine. Slippery reasons belt of aging, poor belt tensioner, tensioner adjuster and so on.

Secondly confirm the variable speed vibration is too large, from n to r gear, d gear changes gears and gear in the drive produces a lot of vibration. Road tests, from 3 to 4 to graduation, and from 4 to 3 when you downshift, variable speed vibration small, graduation and drop between 1 and 2, 2 and 3 between graduation and drop speed vibration. Variable speed only because of excessive vibration of the drive shaft rubber coupling aging or fracture, high oil pressure or within the automatic transmission automatic transmission operation component defect.

First variable speed vibration reason repeatedly for variable speed selection, confirm the status variable speed vibration. Results from n to d location changes, clutch moment of concluding "goo and retorted," sound, vibration and then "click" sound in the driver's seat can also be clearly identified. If the sound is a automatic transmission, is very difficult to understand. Immediately lift the car up, for rotating drive shafts a try, hand shaking can hear "click, click" small sound. Remove the drive shaft, and found the rubber coupling deformation will burst.

According to the above job results, bad parts, the air conditioning compressor drive belt, belt tensioner, tensioner adjuster changed. This three part set to replace the effect better. Abnormal noise because speed, so replacing the rubber elastic coupling drive shaft.

Operating after the driving test, results of abnormal sound of engine completely, switch n from stall to stall and shift in vibration also completely eliminated.