1998 BMW 740i Q&A
1998 BMW 740i Question: loud noise
Check for vacuum leak. I could be grasping but don't skip basics. - raiderron
Are you sure it's coming from the front? Failed vent valve could cause this sound, but it's in the back of the intake manifold. If there is excessive amount of oil in the intake manifold the vent valve failed. If it's coming from the front all the pulleys has to be checked for worn bearings. Zee - ZeeTech
while the engine is running carefully and slowly loosen the oil cap and lift it SLIGHTLY off the valve cover- if the noise goes away it may be a vacuum leak. Be careful- oil will spray out if you lift the cap up too far!! - Greg-Julia
Took my 01 BMW 740i for smog check. Diagnostics listed about six codes, all sensors. Was told car had a misfire?? The car turns on, but it stales like its runing out if power gas and then all of a ...