Inexplicable engine noise

[mick3y]

Good morning,

I was wondering if you could help me with a hint regarding a sound that I noticed coming from the engine. 
The car is a Ford Ka Petrol 1998-2008.
It's not happening all the time and not continuously. It happens immediately after starting the engine, but not every time. I didn't noticed it after having the engine running for a while. But, I may be wrong.

I have uploaded the file so it could be played online.

The noise can be distinguished at 00:05, 00:08, 00:13

Engine noise

 

Thank you

[fiestaecoboostman]

It just sounded like the hydraulic tappets filling with oil a bit slowly, have you checked oil level? When warm it does it sound better?

[mick3y]

Thank you for replying me

It seems that the oil and coolant level are quite low. I will top-up them and check if the sound is still there.

I maybe tempted to say that after the engine gets warm the sound disappears, but I may be wrong. 

I will get back with a follow up after fixing the fluids levels.