1997 Blazer 4-dr. there is a hole in the top of the tank opposite end from where the fuel pump is mounted, any idea what this is for ? I believe this may be the source of my fumes but i cant get to it right now hopefully i'll i will have to do is drop the shield and tighten what ever is screwed in that hole any ideas guys?

 

Is there any way you can take a picture of the area you are referring to?

 

go to auto zone web site and look at the tank i have no means of getting a picture. thank you.

 

Looks like there is supposed to be some EVAP lines at the front of the tank. If I still had my Bravada I'd crawl underneith and check it out for you...

 

Kyle has it correct. There is a vent line that attaches to the front top of the gas tank. Whoever designed it there should be nuetered cause it is a real pain (literally and figuratively) to reach it with your hands. You need to disconnect the hose that attaches to this fitting before you can completely drop the tank. I have done it by lying on my back, with the Blazer jacked up securely, and reaching in there with a long pair of straight blade pliers and squeezing the clamp open so you can slide the clamp out of the way, then you can grab the hose with your fingers and twist it off the fitting. You will scrape and or cut the top of your hand doing it ( a little blood donation ). Remember to re-connect the hose when the tank is back in place. Could be somebody forgot to re-connect the hose (if this was not always your vehicle) or worse, the fitting is broken. You can't really get a good visual on it with the tank in place. If the fitting is broken, you can probably get a replacement at any good "tank bank" recycler. Good Luck.