Generally to hold liquids. Like a Windshield washer or brake fluid reservoir. But also to hold things like a "Vacuum" (yes I know a vacuum does not exists but That's what the car manufacturers call it)
Vacuum reservoirOn the left and right fender well, the one on left is cruise controll & the right is the atc
If you look at the vacuum diagram on the underside of the hood you will see that if a vacuum reservoir was used it would be located near to or off of the Power Brake booster vacuum supply line. I know this because I'm trying to find a vacuum reservoir myself for my 91 Dodge , B250,with 239cid. Why are you looking for one? Henrij.
On a 1998 Windstar the vacuum reservoir tank is under the hood in the back left of the engine compartment when standing in front of the vehicle. Mine has a red and black vacuum hose coming out of it.
When the vehicle is under acceleration it doesn't supply vacuum. The vacuum canister or reservoir holds a vacuum supply to operate vacuum operated accessories until the engine regains vacuum.
There isn't one.
It is a vacuum reservoir. It helps maintain a constant vacuum supply to the HVAC system when engine vacuum is temporarily not sufficient.
Residual vacuum from vacuum reservoir.
The engine's vacuum is mostly controlled by the cam. You can use a milder cam to increase vacuum, or purchase an inexpensive vacuum reservoir to make better use of the vacuum you have.
The headlights require a vacuum to operate down. If there is no vacuum they remain in the up position. You may have a vacuum leak such as a disconnected or broken vacuum line. I have also seen the vacuum reservoir can rotted out and unable to hold a vacuum.
It replaces coolant back into the system by drawing coolant from the reservoir that was pushed out into the reservoir during the heat up process.
Vacuum lines supply vacuum for various functions.