Skip the auto shop - Our mechanics make house calls

Q: Airflow changes when I step on gas pedal

asked by on

When I accelerate, the airflow goes from the dash vents to the defroster. When I let off the gas, it returns to the dash vents.

A: The AC has a vacuum reservoir that is desig...

The AC has a vacuum reservoir that is designed to hold a vacuum to the AC blend doors during acceleration, or low engine vacuum conditions. If this system is leaking, the system cannot hold vacuum to the AC, and will default to the defroster vent when vacuum levels drop. I recommend that you have a mechanic, like one from YourMechanic, check for broken vacuum lines, or a leaking reservoir, through an inspection of your entire AC system.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: How much pag 46 oil goes in a new condenser for 2005 Honda Accord?

Hi there. You will need to add 1 ounce of Pag 46 oil to the condenser. Also if you are just replacing the condenser, I recommend replacing the receiver dryer as well for excessive moisture in the system. The system...

Q: Car not starting

If you are having an issue with the security system, the security light on the dash should light up. I would have the battery tested. A dead battery can cause all kinds of computer issues. If you find that the...

Q: Car ran hot losing power, pulled over put water in radiator car wouldn't start, replaced radiator, still won't start

When you overheated the engine you most likely blew a head gasket and now have low compression in one or more cylinders. Replacing the radiator after overheating the engine that lost power will not fix the fact that the overheating...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.