I have a 2002 Land Rover making a sound similar to a vacuum cleaner when you use the attachments. Sound occurs intermittently from the engine compartment.
Difficult to determine from your description but if this sound occurs intermittently and lasts for several seconds it could be your ABS brake booster pump.
Can you provide any more information ?
Let me guess: it happens when you first start the car, or if it’s colder outside. If that’s the case, the culprit is probably the SAI (secondary air injection) system. Totally normal. You can verify this by a quick glance under the hood. On both sides of the engine, near the spark plugs you should see corrugated copper tubing. If you have this, then between the firewall and the coolant resivoir you’ll see a black blower motor. That’s the device that’s making the vaccuum sound! So no worries, probably