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I bought a second hand 991 S recently. It has 50,000 miles on it. Everything is good except sometimes I get this Gas fume smell (very light) from my air vent. It only occurs when I am driving around 10 - 35mph and when I slow down after exiting a highway. I figured if I am in lower gears and low speed it tends to happen more.
Edit: I found out that if I break under a low speed and come to a stop light or a stop sign it occurs more often. Which is funny because there shouldn't be any oil injection happening when I brake. I understand that it might have something to do with the gas tank. Going to have a mechanic check it out next week.
Here is a forum that I find out which had a similar issue but has no explanation to it. I have a second-hand car so I have no choice to get a refund. But here it is: https://www.6speedonline.com/forums/...ng-stop-3.html
Last edited by Liping Lin; 07-16-2017 at 02:15 AM.
I had a similar problem, and found out it was the tire repair kit, there was a bottle of mobile 1 in there
I checked mine and found nothing smells abnormal. I found a similar post but it doesn't give anything detail about fixing or where the problem came from.
Thanks. I checked and it seems more like something from the AC vent. I might have to get it check next week to see if there are anything leaking. I checked myself with all the components and it seems there isn't any smell when the car is in idle or driving. The smell only comes when I brake a bit harder than usual to a traffic like or a stop sign.
The smell is a bit like natural gas in a way, or something like unburnt fuel. Since the gas tank sits right in front of the car, I suppose it has something to do with that. I hope it is nothing catastrophic.
Resurrecting an old thread. I have had this same exact issue on my 2012 991 S I bought used a few years ago. The problem has recently gotten worse. I notice it most after an HPDE event, but it sometimes happens on normal driving, particularly after hard braking.
Did you ever figure out what it was? I see several threads on this, but none of them seem to have a conclusion.
Hi all, I purchased a 2012 991.1 911s last week, and it has this same issue. It is definitely a natural gas sulphuric smell, not a gasoline smell. Dealership 'couldn't replicate issue' and had no idea what it might be. Has anyone resolved this? All of the threads seem to be dead ends. Thanks! I'm in the process of sorting some issues I should have found pre-purchase, and the forums have been extremely helpful.
Check your battery to see if the vent is there. It is located in the frunk under the plastic panel with the Porsche ingraved in it.
The 991 uses an AGM battery. So, no more vent tube required. Unless, the prior owner put in the wrong (lead acid) bettery. Make sure the proper battery is installed. Good idea.
The 991 uses an AGM battery. So, no more vent tube required.
The dealership mentioned that I have a battery that isn’t Porsche approved. Any chance that it’s a vented type, with nowhere to vent? I’m not familiar with battery venting. Am I looking for something like a nipple that a hose would attach to, or something larger?
edit: looks like you added that while I was responding. That would be an easy fix, I was going to get an approved battery anyway.
The dealership mentioned that I have a battery that isn’t Porsche approved. Any chance that it’s a vented type, with nowhere to vent? I’m not familiar with battery venting. Am I looking for something like a nipple that a hose would attach to, or something larger?
edit: looks like you added that while I was responding. That would be an easy fix, I was going to get an approved battery anyway.
That could be it. The 991 does not have any tubing or vent to connect to, like the 997 and 996 had. You need to buy the proper battery from places like Batteries Plus. I'll post a link to a great DIY you can use.
I had this happen to me as well. It was driving me nuts. I noticed it was worst when backing up or after filling up my gas tank. As it turns out, there was a small hole chewed by a mouse in a gas vent line in the front. The tech had to use a mirror to finally find the damage. I hope this helps!
07-02-2017, 01:50 AM
Gas Fume Smell from 2012 991 S air vent
