3233155 - S13 ENGINE RUMBLING

There is a constant, low frequency noise, only noticeable for short periods of time
Results of the tests
0PRELIMINARY CHECKSAll OKProblems metOperation
Carry out a preliminary test to check the conditions which give rise to the noiseThe noise does not reoccur: Continue to Step 3 The noise increases considerably with the steering in the end of travel position See table   S35 
The noise also occurs with the engine switched off (when warm) Continue to Step 1
The noise increases during braking Continue to Step 2
1MULTI-PURPOSE VALVE CHECKAll OKProblems metOperation
Check the condition of the multi-purpose valve, located on the fuel filler pipe Continue to Step 3 Valve faulty Replace the valve pump Op.   1040A30 
2BRAKE SERVO VACUUM VALVE CHECKAll OKProblems metOperation
Check the condition of the one-way valve on the brake servo vacuum pipe Continue to Step 36 Brake servo valve faulty Replace the valve Op.   3330D20 
3CHECK CORRECT OPERATIONAll OKProblems metOperation
Check that the fault is no longer presentEnd of diagnosisFault persistsSearch for the fault starting from another symptom'