Noise When Accelerating From Stop

[kbrandt]

Hi all.

I wanted to get some opinions. My 01 325i is making a loud roaring noise (like a large fan) when I go from a stop to about 5-10 mph. It then goes away. This seems new and seems to be getting louder. I'm a second owner so i've just started noticing it over the last 4-5 months. Is my transmission or radiator fan about to go? or is this sound normal?

[zibby]

Originally posted by kbrandt@Aug 11 2005, 02:02 PM
Hi all.

I wanted to get some opinions. My 01 325i is making a loud roaring noise (like a large fan) when I go from a stop to about 5-10 mph. It then goes away. This seems new and seems to be getting louder. I'm a second owner so i've just started noticing it over the last 4-5 months. Is my transmission or radiator fan about to go? or is this sound normal?

[snapback]369003[/snapback]

I noticed the same thing on my car, but it happens when engine is very hot , like in "stop and go" traffic.I think it is normal, once sombody told me that is aux air pump and it kicks in for a moment as the engine is hot to reduce harmful staff in exhaust fumes, but again I am not sure about this theory.
,

[kbrandt]

Originally posted by zibby+Aug 11 2005, 01:38 PM--><div class='quotetop'>QUOTE(zibby @ Aug 11 2005, 01:38 PM)</div><div class='quotemain'><!--QuoteBegin-kbrandt@Aug 11 2005, 02:02 PM
Hi all.

I wanted to get some opinions. My 01 325i is making a loud roaring noise (like a large fan) when I go from a stop to about 5-10 mph. It then goes away. This seems new and seems to be getting louder. I'm a second owner so i've just started noticing it over the last 4-5 months. Is my transmission or radiator fan about to go? or is this sound normal?

[snapback]369003[/snapback]

I noticed the same thing on my car, but it happens when engine is very hot , like in "stop and go" traffic.I think it is normal, once sombody told me that is aux air pump and it kicks in for a moment as the engine is hot to reduce harmful staff in exhaust fumes, but again I am not sure about this theory.
,

[snapback]369012[/snapback]

[/b][/quote]
That seems to describe the same thing I experience. It appears to be only happening in stop and go traffic. I live in the south so heat would make sense. Plus the timing of when I started noticing it.

Thanks for the response.

[BMW-ATI]

It does it too mine to, when it's very humid, so it seems normal