Quote:
Originally Posted by Mondaveo
That's interesting.
I've noticed that my MC TDCi sometimes makes a noise several seconds after the ignition is turned off - even well after I've gotten out and locked up - it's not a buzzing, but sounds somewhat like someone operating a foot pump. It goes about half a dozen times (out-in "breaths") and sounds a little like it could be moving fluid. Something in the hydraulics I guess? Was spooky the first few times I heard it!
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That's the egr valve opening and closing for the purpose of cleaning.
It varies from three times and up.
The buzzing is a different noise which occurs immediately on switch off.
It's the turbo vacuum control valve. Cars with pneumatically operated egrs (maybe prior to 2009?) have two of these valves, one for egr and one for turbo. Not all cars do it but it's fairly common and is the subject of youtube videos. One of our two Mondeos nearly always does it, and has done for the last few years without apparent problem. I'm fitting a new valve in it tomorrow, as it's got a turbo issue, not because of the noise.