Years ago I posted about a very similar whirrr noise as you describe with no responses. I have since ignored but still present.
The noise always happen when braking nearing stop and does it again when accelerating from a stop, but harder to hear as the engine is noisier that moment.
As a GUESS, it is a servo from the heating/cooling system inside the box near the passenger feet. Some weird engineering that closes or opens a ventilation gate when reaching a stop and reopens when speed increases again. Perhaps under 5 mph. It is louder at certain season of the year, perhaps winter.
If the climate control computer is programmed to keep some ducts closed or open when stopped, is a second part of the guess.

 

I would replace only its spark plug 5 wire first and no other action for diagnostic purpose. Do not replace the set of wires. Then, evaluate if persistent or not. If cured, you know exactly what was it. Replacing the whole set is your later option... or not.
Next, if persistent failure, inspect health/wetness/porcelain cracks on that spark plug 5. You want diagnosing, not guessing.

 

thank you for your answer.

We did a compression test and the problem was that there was no compression in this cylinder. They in the repair shop think it’s a ring problem or an open valve.

should I do further tests?

 

No compression is of course a more serious issue. Is your shop familiar with this era of LR’s? To suggest rings or valve sounds like he’s guessing. There are other possible causes, eg bad Head Gasket, which isn’t that big of a deal, but a bit time consuming. Other possibilities could be worse.

 

Have them do a cylinder leakdown test, that will determine problem area.