strange noise coming from my gas tank

[termitetrooper]

I have a 1997 GMC suburban 5.7L 2 wheel drive model. I bought it about 2 months ago and it has always made a some what loud bong noise coming from the gas tank, it sound like someone hitting a 55 gallon drum with a rubber malot. This happens when the car sits for about 30 - 40 seconds after I shut it off. It also happens about 30 - 40 seconds after I start it up. It does not seem to effect the performance but I am wondering in the back of my mind is the darn suburban going to blow up on me one day. Does any one else experienceing this problem and what can I do to fix it.

[horse482]

Check the ecm for codes first. You could also try replacing the gas cap could be a pressure problem. The system is designed to maintain some presure but if your cap is not venting correct then that maybe your problem.

[derf]

My 2001 does the same thing. I had it checked at the dealer while under warranty and contacted GM about it. They know about the defect. It's coming from the muffler contracting and expanding. GM had straps installed around my muffler untill they can figure it out. Stated they are working on it. Did not do any good. I don't think they want a another recall. You may want to contact GM and complain.

[termitetrooper]

Originally Posted by horse482

Check the ecm for codes first. You could also try replacing the gas cap could be a pressure problem. The system is designed to maintain some presure but if your cap is not venting correct then that maybe your problem.

Checked for any codes on the ecm non present, I will try the gas cap and see if that helps. Thank you for the rely.

[termitetrooper]

Originally Posted by derf

My 2001 does the same thing. I had it checked at the dealer while under warranty and contacted GM about it. They know about the defect. It's coming from the muffler contracting and expanding. GM had straps installed around my muffler untill they can figure it out. Stated they are working on it. Did not do any good. I don't think they want a another recall. You may want to contact GM and complain.

I appreciate the insite the sound Im hearing is coming from the gas tank though. it does sound like it is expanding and contracting though Im going to try changing the gas cap & see what happens.

[atousc]

I have this exact problem with my 2001 Yukon. Loud clunk noise coming from the rear of the car. Have not been able to figure it out yet. I will update if I get it fixed.

[turnercd]

I have the same noise happening in my 2002 Suburban, anybody had any luck curing it yet??

The other thing mine does that may be related is below 1/4 tank it starts harder than it does otherwise (just takes a couple extra cranks but always starts). Maybe it is related in that the pressure (or lack thereof) is drawing fuel back out of the pump?/?

I may try the new gas cap, but any other thoughts would be welcome.

[atousc]

Originally Posted by turnercd

I have the same noise happening in my 2002 Suburban, anybody had any luck curing it yet??

The other thing mine does that may be related is below 1/4 tank it starts harder than it does otherwise (just takes a couple extra cranks but always starts). Maybe it is related in that the pressure (or lack thereof) is drawing fuel back out of the pump?/?

I may try the new gas cap, but any other thoughts would be welcome.

I had the same problem with a slow start on low fuel. I replaced the fuel pump and it corrected the problem.

[Denalix5]

Originally Posted by termitetrooper

I appreciate the insite the sound Im hearing is coming from the gas tank though. it does sound like it is expanding and contracting though Im going to try changing the gas cap & see what happens.

Believe me it is the muffler or the exhaust pipe. It is a known GM defect. It is caused when the muffler is cooling down and the metal is contracting, or when starting up when cold and the muffler is heating up. Thus the pinging or clanging noise. My noise stopped when I upgraded my exhaust to a Corsa touring. The day I changed the system is the day the noise stopped. Also not all GMC's or Chevy's have this problem. Its hit or miss if you have it.

[Denalix5]

Originally Posted by turnercd

I have the same noise happening in my 2002 Suburban, anybody had any luck curing it yet??

The other thing mine does that may be related is below 1/4 tank it starts harder than it does otherwise (just takes a couple extra cranks but always starts). Maybe it is related in that the pressure (or lack thereof) is drawing fuel back out of the pump?/?

I may try the new gas cap, but any other thoughts would be welcome.

This is probably your fuel pump starting to go bad. This is a known problem on GM trucks. You don't want to let your fuel level go below a 1/4 tank to often. The fuel pump sits inside the gas tank and is usually kept cool when the tank has lots of fuel in it. When you run the tank below 1/4 or close to empty, there is less cold gas in the tank to keep the pump cool. Eventually the pump over heats and goes bad faster than usual. Also be sure and change your fuel filter at every major check up. That's another thing that will mess up your truck.

[bmwgolfguy]

Are you guys sure this isn't just an AMC Gremlin disguised as a Burb?

[Denalix5]

Originally Posted by bmwgolfguy

Are you guys sure this isn't just an AMC Gremlin disguised as a Burb?

I should have said it is a common problem with vehicles that have the fuel pump inside the fuel tank. If happens on BMW's too.

[bmwgolfguy]

I was just funnin with ya.

I no longer own a bimmer. And I won't until they fix the run flat problems that they are ignoring.

[Denalix5]

Originally Posted by bmwgolfguy

I was just funnin with ya.

I no longer own a bimmer. And I won't until they fix the run flat problems that they are ignoring.

No problem, I have an X5 and I've heard of the same problem happening.