[Classic Heartbeat]

Did you vent the tank? If not that is the problem of the tank not holding the shape. Whenever you remove something out of a gas tank it has to be replaced with something, in the case of the gas tank that means air has to replace the gas being used by your truck. If not it will collapse because a vacuum is created inside the tank. The same thing happens with the steel tanks, I know this because every time I fill my Blazer up with gas, when I remove my gas cap there is a big suction noise at the filler followed by a popping noise from the tank as it returns to it's normal shape. The poly tank should return to it's normal shape also, because of the memory charictoristics of Polyetholene. If you want to eliminate the problem use one of the 3 venting places and run a vent hose with a brass filter on the end of it up into one of the frame rails or somewhere it will stay reasonably free of water and dirt. Installed properly, in my opinion, the poly tanks are better than the steel tanks. This is because if something flys up and hits the bottom of your tank it won't dent. WES www.ClassicHeartbeat.com