Gas tank overpressure after sitting in the sun

Asked by malibusteve Jun 21, 2016 at 09:11 PM about the Chevrolet Malibu

Question type: General

I have a 1964 Malibu SS. Not show room quality but I like it. It drives good
and in fair condition.This weekend I filled it up with gas which I don't
normally do just to see how much it would hold.It stopped at about 17
gallons. After it stayed in the driveway for a couple of hours I noticed
something dripping right behind the back tire. It was gasoline dripping from
the frame right next to the gas tank.I went around to the license plate (thats
where the gas cap is) and when I opened the gas cap, about
a quart of gas shot out. It was a very hot day. I siphoned two gallons out
just so that wouldnt happen again.The dripping stopped also. Periodically
throughout the rest of the day I would open the gas cap and relieve
the pressure. I assumed the heat of the day was causing pressure to build
up in the tank.

I checked today and no more dripping. Now, do I have a problem with the
gas cap or the tank? How does the tank normally relieve pressure? Could I
have a hole in the tank and if so where can I take it?

3 Answers
157,475

Bob answered 7 years ago

Gasoline is stored in underground tanks at about 60 degrees F. If you crammed the tank full and it was hot outside the fuel likely expanded, due to the heat, overflowing the fuel tank. Many of the older cars had vented gas caps, but no sure about yours.

1 people found this helpful.
Mark helpful
157,475

Bob answered 7 years ago

Fuel when heated will also build pressure to its vapor pressure. If you tank is unvented the buildup in pressure pushed gasoline out of the tank when you took off the gas cap. Do some reading on vapor pressure for gasoline.

Mark helpful

Your Answer:

Related Questions

  • Gas tank overpressure after sitting in the sun 3 Answers

    I have a 1964 Malibu SS. Not show room quality but I like it. It drives good and in fair condition.This weekend I filled it up with gas which I don't normally do just to see how much it would hold.I...

    Chevrolet Malibu

    -

    General

  • Gas tank size 2 Answers

    What size is the gas tank on 2014 Chevy Malibu

    2014 Chevrolet Malibu LS FWD

    -

    General

  • 09 Chevy Malibu gas tank 1 Answer

    My 2009 Chevy Malibu gas gauge says it's empty and my low fuel light is on but when I go to fill up it will only take 3 gallons andshut off and spits gas back when I try to put more, I forced one ...

    2009 Chevrolet Malibu LS FWD

    -

    General

  • size of gas tank 2 Answers

    How many gallons of gas does the car hold?

    1998 Chevrolet Malibu LS FWD

    -

    General

  • What is the small black box mounted in trunk? 1 Answer

    There is a small black box in my trunk in the area where the speakers go what is is for? Are the wires there if I want to add speakers

    2020 Chevrolet Malibu LS FWD

    -

    General

Malibu

Looking for a Used Malibu in your area?

CarGurus has 1,061 nationwide Malibu listings starting at $2,995.

Postal Code:

Shortcuts

Search Chevrolet Malibu Questions

CarGurus Experts

  • #1
    Gene Arnett
    Reputation
    4,590
  • #2
    T_S_T
    Reputation
    4,380
  • #3
    tenspeed
    Reputation
    4,150
View All

Find great deals from top-rated dealers

Search

Related Models For Sale

Used Chevrolet Impala
4 Great Deals out of 127 listings starting at $3,495
Used Honda Accord
52 Great Deals out of 978 listings starting at $2,995
Used Toyota Camry
51 Great Deals out of 1,099 listings starting at $2,500
Used Nissan Altima
35 Great Deals out of 667 listings starting at $1,995
Used Dodge Charger
36 Great Deals out of 865 listings starting at $5,995
Used Ford Fusion
20 Great Deals out of 436 listings starting at $1,995
Used Honda Civic
206 Great Deals out of 4,071 listings starting at $2,877
Used Chevrolet Cruze
60 Great Deals out of 1,072 listings starting at $2,495
Used Chevrolet Camaro
22 Great Deals out of 471 listings starting at $11,999
Used Chevrolet Silverado 1500
177 Great Deals out of 7,423 listings starting at $6,995
Used Hyundai Sonata
57 Great Deals out of 838 listings starting at $1,543
Used Nissan Maxima
10 Great Deals out of 196 listings starting at $1,450
Used Chevrolet Equinox
96 Great Deals out of 3,203 listings starting at $1,695
Used Toyota Corolla
143 Great Deals out of 2,269 listings starting at $3,495
Used Chrysler 300
28 Great Deals out of 519 listings starting at $6,898

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use. Content will be removed if CarGurus becomes aware that it violates our policies.