What are the three hoses coming from air box on my Buick verano?

My Buick verano has three hoses coming from the air box. One is a vacuum line, I believe one goes to the pcv valve, and the 3rd goes back to the firewall. When that 3rd hose is removed…it is sucking air from what appears to be the firewall. What is this?

My car has 90000 miles.
My car has an automatic transmission.

Experienced mechanics share their insights in answering this question :
Hello, thank you for writing in. There are several vacuum lines associated with the engine intake and throttle. One of which that does run along up towards the firewall is the brake booster line. This vacuum helps assist the master cylinder in maximizing the brake assisting. The others are for the EVAP canister, the fuel pressure regulator, super charger if equipped, and manifold pressure source. You will find the best sources for diagrams is in repair manuals for the vehicle. You may also want to locate the component on the other side to see what the purpose of this line is. For more diagnostic help, contact our service department to schedule an appointment.

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You can call it a vent hose, it is part of the PCV system. It provides filtered air to the crankcase. Actually that is the air intake line for the PCV system.
The air intake hose`s function is to connect your vehicle`s factory air box (or aftermarket cone-style air filter) to the intake manifold bolted to the engine. Aftermarket units are often installed to increase airflow to the engine, which can result in increased power output.
by having the vacuum hose and PCV leading to the intake the engine will burn off the hydrocarbons instead of releasing them in to the atmosphere. Removing pressure from the crankcase also assists in minimizing oil leaks. So it`s an important part of the engine by reducing emissions and reducing crankcase pressure.
That`s the idle air hose. One end goes to the air intake pipe, the other end to the idle air control valve which sits right under the throttle body. If one end of the hose is loose, there should be a free spot for it nearby. That`s the idle air hose.
The Positive Crankcase Ventilation (PCV) valve hose is a hose running from the valve cover on the engine to either the intake air box or the intake manifold. The PCV valve is activated when crankcase pressure rises in the engine when running.
vent hose (pcv system, valve cover to intake / air filter) genuine Toyota part.
When you install a cold air intake, you move the air filter outside of the engine compartment so that cool air can be sucked into the engine for combustion. This cool air is denser with oxygen, which means there is more fuel for combustion and more power for your vehicle.
Manifold vacuum is an effect of a piston`s movement on the induction stroke and the choked flow through a throttle in the intake manifold of an engine. It is a measure of the amount of restriction of airflow through the engine, and hence of the unused power capacity in the engine.
Vacuum leaks can develop in many locations, including the intake manifold, throttle body evaporative emissions system, power brake booster, and several other places, because some vehicles have a multitude of vacuum hoses.
If you`re looking for style and performance, we suggest going with the open-airbox, and if you want nothing but performance, we recommend going with the closed airbox. Note that to get the most out of your cold air intake, most of them will need a tune to see rear-wheel horsepower results you desire.
An inlet hose, or sometimes referred to as a jumper hose, supply hose, or feeder hose, is simply a short garden hose that supplies water from the faucet or spigot to the hose reel.
The passage through the cylinder head in four stroke engines, the intake port, connects the intake manifold to the cylinder.
If the air filter housing is disconnected, your car`s performance will reduce drastically, and the lifespan too. This is because the air filter housing prevents dust, and other dangerous particles from getting into your combustion chamber.
The upper radiator hose is where the hot coolant enters the radiator from the engine. It cycles through the radiator, cooling as it goes.
A hose connects the top of the PCV valve to a vacuum port on the throttle body, carburetor or intake manifold. This allows the vapors to be siphoned directly into the engine without gumming up the throttle body or carburetor.
The supply hose is connected to the fuel filter. The return hose is connected to the top of the fuel tank. The vapor return hose is connected to the charcoal canister.
The throttle body generally attaches directly to the intake manifold`s plenum and features an electronically controlled or cable actuated plate to control the amount of air to be let in.
The plenum is the large cavity at the top of the manifold. It acts as a reservoir, holding the air until it`s ready to go into the cylinders. The plenum evenly distributes the air to the runners before it passes through the intake valve. The size of the plenum impacts the engine`s performance.
Standard performance air intake kits locate the air box and filter within the engine compartment at or near the stock location. Cold air intake kits relocate the air box and filter outside of the engine compartment, usually near the fenderwell.
The cold-air intake tube is usually located where it can pull air from outside the engine bay, such as a fender, the grille, or hood scoop. The cold-air intake tube marks the beginning of air`s passage through the air intake system, the only opening through which air can enter.
The purpose of a cold-air intake is to find cold air in an otherwise hot under-hood environment. It can do this by drawing air from above the hood, under the front bumper or a spot inside the engine compartment that isn`t as hot as other places.
Vacuum hoses can be found throughout many vehicles, with cars generally having as many as a dozen working inside them. Generally, they are made out of rubber or rubber like materials. While modern electric cars may not have vacuum hoses, just about any car that runs on gasoline will.
Vacuum is the difference in air pressure between the inside of the intake manifold and the outside atmosphere. The pressure difference creates suction and helps to draw air into the engine. Engine vacuum is a required condition for a gasoline engine to run.
This is certainly the case with leak detection, with four main methods being employed: the bubble test; pressure decay test; pressure rise test; and helium sniffer mode/helium vacuum mode tests.

Relevant Questions and Answers :

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What are the three hoses coming from air box on my Buick verano?
ANSWER : Hello, thank you for writing in. There are several vacuum lines associated with the engine intake and throttle. One of which that does run along up towards the firewall is the brake booster line. This vacuum helps assist the master cylinder in maximizing the brake assisting. The others are for the EVAP canister, the fuel pressure regulator, super charger if equipped, and manifold pressure source. You will find the best sources for diagrams is in repair manuals for the vehicle. You may also want to locate the component on the other side to see what the purpose of this line is. For more diagnostic help, contact our service department to schedule an appointment.

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The loud rattling noise you heard is a classic failure pattern for all A/C compressors. Other than not having cold air and effective defrosting, your car will run and drive as normal. If you are experiencing other symptoms, then you have other problems.

I recommend the following service if you decide you want your A/C compressor replaced, by a certified technician from YourMechanic; AC compressor replacement.

Good luck!

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