Skip the auto shop - Our mechanics make house calls

Q: Gas tank implodes/ won't fill.

asked by on

2001 Silverado. Gas tank implodes while driving then when I open the gas cap, it sucks a lot of air in and the tank goes back to normal. Gas tank also won't fill past 3/4 full. I've replaced the charcoal canister and the vent valve/solenoid. What else could it be?

Your fuel tank is going into a vacuum when the engine is running. The vacuum condition is causing the fuel tank to collapse and the gas cap is supposed to let in fresh air from the outside to keep the vacuum build up. I would recommend having the fuel tank checked to make sure it is not damaged and then check the fuel cap vent to see if it is stuck and gas cap needs replaced. Your fuel tank vent line to the carbon canister should be checked to make sure it is not pinched and flows freely to the carbon canister to the fuel tank.

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: Gas tank door burnt black.

The most common cause for a P0440 code is the fuel cap seal. I suggest making sure that the fuel cap is tight by turning until it clicks. If you are sure that your fuel cap was tight, replace the...

Q: Chevy Tahoe has a heavy idle on startup, and will stall out when put in gear

Hi Tony. There are several possible sources of this problem, ranging from a damaged or loose vacuum line, faulty idle control valve or EGR valve and mass air flow sensor. If you'd like to have a professional mechanic come to...

Q: My truck turns over but won't start.

When a truck won't start, it's usually going to be an ignition or fuel system-related malfunction. The fact that your gas gauge was "ticking" a bit may be an indicator that an electrical problem exists, causing the ignition system to...

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 Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.