Another weird noise
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Another weird noise
I read through 13 pages of "noise" in the forums to no avail, so...
My 99 (4.6L 4x2 XLT, no LLS, rear air) Expy has a gas problem during idle. It sounds a lot like flatulence, actually. It is coming from the left rear area. She idles fine then farts a little, then idles for three or four more minutes, then more noise. My kids get a big kick out of it, but it is kind of embarassing.
This is not a joke. Anybody else experience anything like this?
My 99 (4.6L 4x2 XLT, no LLS, rear air) Expy has a gas problem during idle. It sounds a lot like flatulence, actually. It is coming from the left rear area. She idles fine then farts a little, then idles for three or four more minutes, then more noise. My kids get a big kick out of it, but it is kind of embarassing.
This is not a joke. Anybody else experience anything like this?
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A bit of a longshot, but:
If you have rear air, then you have rear heat as well, with a seperate heater core (with engine coolant circulating through it) located in the back of the truck on the driver's side. I wonder if trapped air in the core is creating a gurgling noise. Run the truck for a little while with the rear heat set for maximum heat (you don't need to run the fan motor at any but the lowest speed), let the engine cool, then check out the engine coolant level. If the level is low, top it off to the recommended level. Go through the drill again, and see if the level drops further (as a consequence of the system burping out more air).
If you have rear air, then you have rear heat as well, with a seperate heater core (with engine coolant circulating through it) located in the back of the truck on the driver's side. I wonder if trapped air in the core is creating a gurgling noise. Run the truck for a little while with the rear heat set for maximum heat (you don't need to run the fan motor at any but the lowest speed), let the engine cool, then check out the engine coolant level. If the level is low, top it off to the recommended level. Go through the drill again, and see if the level drops further (as a consequence of the system burping out more air).
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Joined: Mar 2004
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From: Grand Island, NY
Can you get the noise to occur on a regular basis or under certain situations ? It may be the gas cap venting pressure or vacuum from the gas tank. If you know how to make it happen or when it occurs , try running it with the gas cap loose, not turned all the way until it locks or better yet just set it in the opening with out turning it. If the noise stops then you know it is related to pressure or vacuum in the fuel tank. That would lead you to looking into the fuel EVAP system or the charcoal canister, stc.
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Originally Posted by scholzee
Can you get the noise to occur on a regular basis or under certain situations ? It may be the gas cap venting pressure or vacuum from the gas tank. If you know how to make it happen or when it occurs , try running it with the gas cap loose, not turned all the way until it locks or better yet just set it in the opening with out turning it. If the noise stops then you know it is related to pressure or vacuum in the fuel tank. That would lead you to looking into the fuel EVAP system or the charcoal canister, stc.
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Joined: Oct 2000
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From: All over Texas
Originally Posted by PaulC
Just bear in mind that running with the cap loose or off will trigger the "service engine soon" light.
Not necessarily. In the heat down here, I sometimes fill up with the engine running and AC on for kids, wife and dog.
The PCM has to make a couple full cycles and pick up the same problem multiple times before a code is thrown.
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I changed the gas cap. It stopped. Until I slowly removed the new gas cap and it rattled out a small one, but the identical sound as before.
So, apparently it was the cap. Thanks for all the great advice.
So, apparently it was the cap. Thanks for all the great advice.
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