Thumping noise when starting my cold car

[Blade74]

My 2010 TDV8 Vogue makes a thumping type noise every 2-3 seconds when I first start the car.
Its not very loud but you can just hear it.
It remains me of the sound a concrete pump makes.
It goes away after 5 mins or so.
Any ideas?
Is it the EGR trying to clean itself?
Oh and my air conditioning is always on!

[rar110]

That's a new one. Never heard of that being reported. Does the EGR make the normal noise when you shut the engine off? Any idea where in the engine bay it comes from?

[Blade74]

It does I believe but I'll re check tomorrow.
I'd say the right side top of the motor looking at the car from the front.

[Blade74]

Although it sounds a bit lower when you're in the car.
Ill check it some more and post my findings.
I think I need a stethoscope! :-)

[BobD]

Do you mean that the compressor is always running or that the air con is always cooling? The compressor doesn't stop turning as it is variable displacement but if you turn the cooling off it shouldn't cool, even though the compressor is still turning. The ECU just varies the displacement to zero so it doesn't do anything.

[Blade74]

Do you mean that the compressor is always running or that the air con is always cooling? The compressor doesn't stop turning as it is variable displacement but if you turn the cooling off it shouldn't cool, even though the compressor is still turning. The ECU just varies the displacement to zero so it doesn't do anything.

I just mean that I never turn off my air conditioning.
When I start the car cold it is on straight away and possibly trying to cool.
Therefore it could be a noise from the AC compressor??

[BobD]

It could be the fan on the way out. I had a similar noise on start up but I would describe it more as a click. I think the fan gets tested after start up and mine would not engage so it just kept clicking until the test was finished. I ended up with a new viscous hub. Probably not your issue but you never know.