Faint Natural Gas Smell

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Joined
Mar 6, 2016
Threads
7
Messages
48
Location
Northern California
2004 LX - Has anyone else caught a wiff of natural gas in the cabin of their truck? I know that catalytic converters can smell when they go bad but this is not that strong. It's almost a propane smell not gasoline or exhaust fumes.
 
How long have you had the truck? Long shot, but due to high cost of Freon, home mechanics have been refilling AC with propane.
 
How long have you had the truck? Long shot, but due to high cost of Freon, home mechanics have been refilling AC with propane.
Long time to answer... I got the truck in the first part of March with 75K miles. Still getting the smell from time to time.
 
This may sound crazy but I had the same smell, It was gasoline fumes but it smelled more like natural gas with the A/C on. Turns out I had a cracked vacuum line that connects the purge valve to the charcoal canister. Replaced the hose and the smell was gone.
 
If you are not familiar with smell of gear oil you might mistake it for that smell. Do you have any oil leaks from front or rear differentials or transfer case?
 
This may sound crazy but I had the same smell, It was gasoline fumes but it smelled more like natural gas with the A/C on. Turns out I had a cracked vacuum line that connects the purge valve to the charcoal canister. Replaced the hose and the smell was gone.

I would check the charcoal canister connections. That smell is unique...
 
You might have valve cover gaskets that are starting to leak and you got a whiff of crankcase gases? The bolts for the covers are notorious for backing off over time and it's normal to find a few not even finger tight. Worth checking and retightening the loose ones - they only need a few inch pounds, don't over tighten and strip the Al. thread.
 
This may sound crazy but I had the same smell, It was gasoline fumes but it smelled more like natural gas with the A/C on. Turns out I had a cracked vacuum line that connects the purge valve to the charcoal canister. Replaced the hose and the smell was gone.

This is on a 2004, I believe the fix here is to replace the entire canister. It's located above the spare tire. Someone correct me if I'm wrong, but you cannot just change the valve or the line on the newer canisters, it all comes as one part.
 
I would check your differential breathers... if clogged from rust they will not operate and pressure of gear oil will bust the seals and give the faint smell of rotten egg / natural gas. Ask me how I know...
 
This is on a 2004, I believe the fix here is to replace the entire canister. It's located above the spare tire. Someone correct me if I'm wrong, but you cannot just change the valve or the line on the newer canisters, it all comes as one part.
I'm doing a little research on the canisters... I'm wondering if there is any way to be sure it's the problem before I spend the $$$ to do it? I think it's recommended to change out at the 90K service anyway.
 
When the seal gets blown it will push gear oil in to hand brake shoes /drum area and it is NOT easily visible (wet spot near the edge of drum when parked for longer)... , but the smell will be present.
 
PROBLEM SOLVED.

The cabin air filter was 99% blocked. This car, a 2004 LX470, had only 75000 miles on it when I bought it. It was used as a winter car at a ski cabin at Lake Tahoe. It sat idea for most summers over the last 12 years. A mouse had used the area just before the filters as a home and had moved a bunch of nesting materials into the area. Lots of foam, very small pieces, and other stuff had totally clogged the filters.... and I do mean clogged. The cabin was getting 0 ventilation. I ran all day today without cabin filters and detected no gas smell, none. New filters are going in tomorrow.
 
Check for water leaks in the cargo area, mine would smell nasty until it was driven and got vented, it was only a small leak. After fixing the leak and a good clean no more smell, even if left for a couple of weeks.
 
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