How to pop a dent out of an SJ gas tank

[SXIPro]

I just pulled my gas tank to make room to work on some stuff and noticed it was 'sucked' in pretty substantially on the B-Pipe side of the tank, so apparently at some point my tank vent crapped out. How would I go about popping the dent out? I tried muscling it out using a long 3/4" dowel and sort of prying on it, but it didn't move at all. If I emptied the tank and sealed it up and maybe blew compressed air into an open inlet maybe?

 

[WFO Speedracer]

Pressurize it with air and leave it out in the sun for a few hours.

 

[Quinc]

Starting fluid and a match! Works well on tires.

 

[Sanoman]

I just pulled my gas tank to make room to work on some stuff and noticed it was 'sucked' in pretty substantially on the B-Pipe side of the tank, so apparently at some point my tank vent crapped out. How would I go about popping the dent out? I tried muscling it out using a long 3/4" dowel and sort of prying on it, but it didn't move at all. If I emptied the tank and sealed it up and maybe blew compressed air into an open inlet maybe?

Flush and clean the tank really well. and let it air out for a couple days.That should be enough to get the fumes out. Take a heat gun and warm up a large area around where it’s sucked in. Use your dowel with some turf around it to gently push the area back out. Just get the plastic barely warm enough to move, cause to much heat will distort the tank. That should work

 

[SXIPro]

Flush and clean the tank really well. and let it air out for a couple days.That should be enough to get the fumes out. Take a heat gun and warm up a large area around where it’s sucked in. Use your dowel with some turf around it to gently push the area back out. Just get the plastic barely warm enough to move, cause to much heat will distort the tank. That should work

This is pretty much exactly what I ended up doing. I didn’t air it out for a couple days but i washed it inside and out with Dawn and hot water and rinsed it forever then left it out in the yard the rest of the day in the sun. Hit it with the heat gun and used the rubber coated handle end of a framing hammer to massage the dent out. Kind of like what the paintless dent repair guys do to car dents and dings. Worked like a charm plus my tank is a lot cleaner looking now. Win/win.

 

[Sanoman]

The paintless dent removal guys do plastic bumpers like that.So figured it would work on a tank. Glad that worked out for you

 

[TheBuzzard]

Gas tanks are made out of hdpe. High density poly ethelene. Sun eats that plastic with a quickness so keep your hoods on. I've fixed a couple holes in tanks by lighting a stick of hdpe on fire and dripping it on the hole. Hillbilly plastic welding

 

[bird]

In the north we fill things with water, put in freezer or outside and let it FREEZE. Water expands when frozen...or ice would sink. This works for dents in exhaust pipes and more.