andya 0 Report post Posted March 4, 2008 Hello, just a quick question if i may - I drive a 318i E46 1998 - since I bought it last year it has done something that i never thought about at the time but several people have noticed it and bought it to my attention. After the car has sat idle overnight or during the day upon start up there is a very noticeable vacuum sound that lasts for about 45 seconds to a minute. it only does this after about 5-6 hours of not being used- otherwise it doesn't occur. As far as i can tell it doesn't impede the performance in any way but then again I never even noticed the sound until someone mentioned it. Any ideas? many thanks, Andy Quote Share this post Link to post Share on other sites
Yuen 16 Report post Posted March 4, 2008 My 2 cents - sounds like the vacuum leak occurs when the car is cool. Could it be that when when warm the small leak in a hose, for example, disappears due to the hose expanding from heat? Quote Share this post Link to post Share on other sites
*Glenn* 854 Report post Posted March 4, 2008 Hello, just a quick question if i may - I drive a 318i E46 1998 - since I bought it last year it has done something that i never thought about at the time but several people have noticed it and bought it to my attention. After the car has sat idle overnight or during the day upon start up there is a very noticeable vacuum sound that lasts for about 45 seconds to a minute. it only does this after about 5-6 hours of not being used- otherwise it doesn't occur. As far as i can tell it doesn't impede the performance in any way but then again I never even noticed the sound until someone mentioned it. Any ideas? many thanks, Andy If it has an EGR valve and air pump (electric) thats what you will be hearing. Not all 318's have them though. Its located on the drivers side by the radiator. When the EGR valves pack up, moisture gets into the pump and damages the bearings. This makes the noise louder. They also have an air filter located on the other side of the radiator (passengers side). Take the hose (plastic clipped hose) of the EGR valve that goes to the air pump with the engine running (warm) and see if the EGR valve is spitting out moisture or exhaust fumes. It shouldnt do that. Hope you can make sence of that Cheers Glenn Quote Share this post Link to post Share on other sites
