Soft "Clack" every 4-5 seconds under the hood when Idling

[bcolins]

When I'm sitting at a light with engine idling, I hear a very faint "clack" every 4-5 seconds,.....sounds like its coming from the engine bay (or maybe firewall area?). It is VERY regular in its interval and sound,...never varying.

Anyone else experienced this?

Brian in San Antonio

[bcolins]

was noticing this again while idling the other day,..... it was clacking about once every 2 seconds,....then after a few minutes,.....it stopped. Anyone have any thoughts on this?

[Unkleschilke]

Want to ressurrect this... I am troubleshooting a 2007 e83 with the N52 and GM6. I hear this same soft clack. Every 5 seconds or so.

OP, did you ever figure it out?

[bcolins]

I got a response elsewhere that it was common,....cant recall what it was thought to be,.....possibly a water circulation valve. not sure. I decided not to worry about it.

[Qsilver7]

On my Bimmers with the M62/M62TU engines...the evaporative purge valve made a noise like you mention...and it would do it at idle. That's because at idle...is when the recovered fuel vapors (from the fuel tank) were being "recycled" to be burnt inside the engine.

[E38flagship]

turn your hvac off and see if it stops I had the same problem with mine and my brothers x3 you could feel it where you rest your foot . Replaced my heater valve with a used one never had the problem again.