2014 sierra 5.3 smells like propane

Jliebrecht · June 10, 2018

Has anyone else had this issue, I have had the same thing happen to my 2014 gmc Slt 1500, was pulling horse trailer when first noticed and now it’s happens for a little bit every time I drive it.

Red_5 · June 21, 2020

I have the same issue now too. While towing our travel trailer recently we started smelling propane when we stopped. With propane tanks on the trailer we were pretty freaked out. It’s still doing it with the trailer disconnected. Usually get the smell when we park after driving in the car. Smell outside the truck seems to be the strongest in the driver side wheel well. We have a ‘15 Sierra SLT 6.2 4x4 Max Tow if any of that matters. We still have a powertrain warranty so when we get home I’ll take it in and see what they have to say. I found another link the other day talking about a TSB on it.

Red_5 · July 5, 2020

Anyone know how you locate the TSB for this problem? I've seen in other threads there's a TSB but not sure how you locate it to share with the dealership. I'm hoping to take my truck in soon. Thanks.

Dave Chiek · January 27, 2024

I have a 2017 Silverado LTZ that started having a propane smell especially inside the cab after a friend used the truck to pull a boat home. Anyone have any ideas what it might be?

FMyrick · December 25, 2024

On 5/31/2018 at 11:55 AM, cruser7 said:

I found my propane smell, and fixed it. Coming from the front differential vent. I changed the fluid, rerouted the vent line to the rear of the vehicle up by the gas cap door and installed a inline gas fliter. Smell has disappear. Sound crazy, but its gone thank god.

I have this same smell in my 2015 Chevy Silverado. I've had guys rip me off changing my fuel injectors, performing a tune up, and changing my cabin filter.. Yet i still smell it.. it's feint when my heat is off but really strong when my heat is on or when i step out the car after driving a while.

FMyrick · December 25, 2024

How did you resolve the problem??

superdave160 · December 30, 2024

I didn't see it mentioned earlier in this thread, but it could be the cats overheating. Take a code reader with live data display and see what the cat temps are when you smell the propane smell. The smell could be cause by heating of the adhesives and/or dyes in the carpet.

BIGDOGx · December 30, 2024

14 hours ago, superdave160 said:

I didn't see it mentioned earlier in this thread, but it could be the cats overheating. Take a code reader with live data display and see what the cat temps are when you smell the propane smell. The smell could be cause by heating of the adhesives and/or dyes in the carpet.

The problem was quoted in the post above with it being a Front differential vent. Even before reading this post to me the only substance that could smell a tad like propane gas is gear oil imo, as the stuff is rank smelling, especially older dirty gear oil.

superdave160 · December 31, 2024

13 hours ago, BIGDOGx said:

The problem was quoted in the post above with it being a Front differential vent. Even before reading this post to me the only substance that could smell a tad like propane gas is gear oil imo, as the stuff is rank smelling, especially older dirty gear oil.

I was a mechanic in the 80's and 90's and I've seen instances where cats overheat and cause odors in the cab. I've never seen any events where the differential vented enough fumes to be detectable in the cab. I worked on 1/2 ton and 3/4 ton trucks with big tires and solid axles. I believe that it is more likely a cat issue causing the smell than the differential vent, which is why I posted my comment. If I am wrong then I am wrong. I was simply providing some information from my experience so that the person who posted the question could consider it.

BIGDOGx · December 31, 2024

8 hours ago, superdave160 said:

I was a mechanic in the 80's and 90's and I've seen instances where cats overheat and cause odors in the cab. I've never seen any events where the differential vented enough fumes to be detectable in the cab. I worked on 1/2 ton and 3/4 ton trucks with big tires and solid axles. I believe that it is more likely a cat issue causing the smell than the differential vent, which is why I posted my comment. If I am wrong then I am wrong. I was simply providing some information from my experience so that the person who posted the question could consider it.

As i did the same thing, i am only repeating what a person in this very post claimed fixed his issue.

Quote

I found my propane smell, and fixed it. Coming from the front differential vent. I changed the fluid, rerouted the vent line to the rear of the vehicle up by the gas cap door and installed a inline gas fliter. Smell has disappear. Sound crazy, but its gone thank god.

Gear oil, i'm sure since you are mechanic will agree smells rank and foul and i can find it possible for it to smell a bit like Propane.