EGR valve 'whistling' after engine shut-off

[AVillatoro]

Hi all,

My 1.4D4D engine started hunting for idle when cold, so I removed and cleaned the soot accumulated in the EGR valve on the left side of the engine (the one that gets air from the intercooler).  This cured the rough idle, but now the engine makes an odd 'whistling' noise a few seconds after shutting off.   It sounds like one of those 'tuning whistles' musicians use.   As it whistles, I can see the vacuum pot that operates the throttle valve inside the EGR valve body moves - as if trapped boost is slowly being released somewhere.   The whistling sound is a bit faint on the video I've attached, but it's there.

This is the first time I've heard my engine do this - it did not do it before or during the rough idle showed up. 

Why is it doing this??  How do I stop it??

[Madasafish]

How did you clean the soot?

 

It sounds as if the valve is closing very slowly due to dirt  build up

[AVillatoro]

Most of it I was able to scoop out with a small flat screwdriver.  The small passage between the two halves of the valve body was completely clogged with soot.  I cleaned that out using brake fluid and running a thin wire through the orifice until it easily come out the other side.  I don't think there's much soot left in there at all - to stop the valve closing quickly.

[Madasafish]

Hmm I would only use carb cleaner - a volatile liquid which evaporates leaving no residues..  (Yes I cleaned mine using it)

 

Brake fluid is not volatile and is heat resistant - I suggest you  have left a greasy sticky mix of brake fluid and carbon..ideal to clog up any EGR valve. (I have never used brake fluid as anything but - brake fluid).. (It also strips paint)

[bathtub tom]

18 minutes ago, Madasafish said:

(I have never used brake fluid as anything but - brake fluid).. (It also strips paint)

I find it's excellent at quietening squeaky, rubber suspension bushes.

[AVillatoro]

34 minutes ago, Madasafish said:

Hmm I would only use carb cleaner - a volatile liquid which evaporates leaving no residues..  (Yes I cleaned mine using it)

 

Brake fluid is not volatile and is heat resistant - I suggest you  have left a greasy sticky mix of brake fluid and carbon..ideal to clog up any EGR valve. (I have never used brake fluid as anything but - brake fluid).. (It also strips paint)

I thought it looked all very clean and soot before I fitted it back to the engine.  But, you might be right and so I'll take it off and clean again - with carb cleaner spray.

This is not the EGR valve, BTW.  That one is on the other side of the inlet block, closer to the Battery.   The part I took off doesn't have the EGR poppet valve in it.  It has a butterfly valve similar to the one in petrol engine - I'm guessing it closes to create vacuum in the inlet manifold to encourage exhaust gas flow from the EGR valve on the other side of the manifold.

[AVillatoro]

21 minutes ago, bathtub tom said:

I find it's excellent at quietening squeaky, rubber suspension bushes.

I'm no bushes expert, but I'd say if they can be made quieter by adding any sort of lubricant, then they've dried out and will soon start cracking, so best to just replace them.  

And won't brake fluid chemically attack the rubber the bushes are made from?

[bathtub tom]

1 hour ago, AVillatoro said:

And won't brake fluid chemically attack the rubber the bushes are made from?

It doesn't attack the rubber (or whatever material) brake and clutch hydraulics are made from. That's why you'll often find an old jam jar with old brake fluid and a paint brush in old, amateur mechanics garages.