My 2000 GMC has started to have a very strong odor of natural gas
coming from the front. If I drive with the windows open even a
little, it comes pouring in. Windows closed with or w/o the a/c on,
absolutely nothing. Really weird, it is the *exact* same smell of
home gas when you turn on the stove, you know, that odor they put in
it so you know there's a gas leak? We even thought at first I had
forgot to turn the gas off in the trailer we were pulling, but nope
that was not it.

There is nothing leaking onto the ground anywhere and the truck runs
fine, recently had it all checked out and fluids changed. Any idea
what fluid in the car would smell exactly like this and why it would
be so strong coming in when the side windows are open? Or what part
might smell like that if it was burning or something?

thanks
Frenchy

Oxagen sensor ?? My GMC stunk like that . I got lucky ,brother unpluged
it as a juke. He still hasn't figured out who took his valve stem cores
five years later. I have a verry good memory. BTW I did that right
after his wedding.

Jerry


http://community.webtv.net/awoodbutcher/MyWoodWorkingPage



http://community.webtv.net/awoodbutcher/1974RuppCentair

"frenchy" <mf101723 (AT) msn (DOT) com> wrote

The odorant they put in natural gas is methyl mercaptan...there's nothing in
a vehicle's systems containing this compound. When you eat asparagus, this
is the stuff that makes your urine stink afterwards. A catalytic converter
at operating temperature produces small quantities hydrogen sulfide which is
a powerful odorant (rotten egg smell), detectable at a few ppm by people.
It's usually released and from the coverter after low temp operation when
it's adsorbed by internal cat washcoat and released on high temp operation
of the cat. Unless the exhaust system is leaking past the converter and
seeping from under the car to the front and sides this is usually only
detectable from rear. Is it possible you are smelling exhaust gasses wafting
back from the pipe?

Augustus wrote:
More likely that the battery is overcharging and boiling off sulfuric
acid fumes.

On Wed, 12 Aug 2009 23:14:27 -0700 (PDT), frenchy
<mf101723 (AT) msn (DOT) com> wrote:

I guess that you have checked and sniffed all fluids
from engine compartment, checked belt tensions.
Checked that there is no bearing burning out from
alternator, checked that auxiliary electric cooling fans
are not jammed and burning hot..

That smell could come from car battery.

Check battery water levels if you dont't have
maintenance free battery. fill if necessary. Check also
that there is not overfilling in any of the cells.
Check charging voltage at different engine revs. 14.2V
max would be ok.
Usually US made alternators charge little bit higher
level than EU made automobiles.
Check battery voltage with engine turned off. put some
load for battery, lights on and check that battery level
won't drop excessively. This is to check that there is
no battery cells shorted.
This all is to check that there is no battery over
charging at any cells or whole battery that would boil
the battery water and overspill battery water thorough
overspill tube or blowing boiling gases out of the
overspill tube or water filling caps. (Hydrogen, Oxygen)
Clean battery and check that there is no cracks or
leaks. Also check that battery is in its original
shape, not ballooned or otherwise disformed.
Grease battery connections with oxygen free grease or
battery spray. Check also battery connections and that
the battery is solidly installed.

If that smell doesn't come from battery, at least your
battery is now overhauled.

--

Or that smell could come from raccoon that is half
rotten and stucked in your radiator (c>

AJ.

_____________________________
Gas price at the moment $7.30/gal
8-12 miles /gal with Chevy SS454
_____________________________

Thanks I'll check out the battery levels and the voltage, the voltage
gauge seems to read ok, and will check the fan. This is definitely
not wafting up from the rear, that's what we thought at first since we
first noticed it with the trailer back there, but even with no trailer
it is exactly the same amount of stink from the windows while driving.
I'm almost positive it is not some other fluid in the car as I'm
familiar with their smells. Also it is definitely not that rotten-egg
smell associated with cat convertors, so pretty sure it's not an
exhaust leak, just doesn't smell like an exhaust, fuel or cat conv.
odor. The racoon joke is almost what I thought at first, I started
hunting for some dead cat under the hood. I suppose their could be an
animal hidden somewhere that I can't see it, this did happen first
when we left a camping area, I'll look some more.
Thanks everybody!
Mark

I just went out to the parking lot... battery looks fine, all cells
are filled and identical, cell caps are on good, no bulging or leaks,
terminals are nice and clean, dash gauge reads slightly above 14
volts. Belts are all new and look fine and correct tightness. Man
I'm really starting to think maybe there may be a critter stuck
somewhere under the truck after all, time to get out the work light
tonight in the garage. That's the first thing I thought of when I
smelled it!
Mark

frenchy wrote:
Could be a cooked critter over the cat. Not a fun thing to clean up.
Wasn't anyone around the campsite who had some human scent masking
product? A bit of the stuff I use to hide my scent from animals while
heading to the tree stand could sure make a stink. (I know it can
because some A%%WIPE poured about a tablespoon of skunk musk in the
window wash jug on the truck a few years ago... The only way I got rid
of that was to replace the tubing, jug and pump!!!!)


--
Steve W.

"Steve W." <csr684 (AT) NOTyahoo (DOT) com> wrote


Thanks for the laugh...

"frenchy" <mf101723 (AT) msn (DOT) com> wrote

How long has it been a problem? If a dead animal is the cause, it's not
likely to cause a problem, or at least one of this magnitude, for more than
one or two weeks.