1995 Dodge Ram 1500 V8 4x4 Short Bed Automatic

I have notice when my gas cap it tightened down and its hot outside, my gas tank starts leaking. Then when I loosing the gas cap I hear pressure escaping and the leak will stop. Whats going on?

Thanks

 

Sounds as if your Evaporation system isn't working properly.

Look for the vent hoses around the tank, make sure none of them are capped/plugged.

 

Where exactly is it leaking from?

 

I look under the truck, and I see it running down the bottom of the tank and dripping on the ground.

 

Front or back?

 

Really need to try and isolate where the gas is leaking from. It could be the tank, a fuel hose coming off the tank, the evaporation system, the metal fill tube (mine had a hole in it from rust), etc.

 

+1... Need to find where it's leaking from. Could be the gasket around the fuel pump too I suppose. And I have a couple new fuel pump gaskets if you need one.

 

So I dropped the thank and inspected it. Looks ok, no pin holes or nothing and the hoses are fine. I reinstalled it and tightened the gas cap. We I came home work today, and its only about 78 degrees out, my tank was leaking again. I got under the truck and saw the gas bubbling out of the auxiliary port or nipple. Its on the pump module.
Does this mean my emissions system is faulty? The tank is connected by a hose to the emissions canister to store the fumes. Maybe this is not working?

 

If you are getting liquid gasoline out that port, something is indeed wrong. That is just to capture vapor from the tank. Might need to drop the tank, and pull the pump module, and see what's up.

 

You're going to have to pull the tank and inspect the seal around the pump and the lines, as well as the lines themselves.