Gas smell after cold start
Thread Starter
Newbie
Joined: Jun 2019
Posts: 1
Likes: 0
2015 C300
Gas smell after cold start
Hey All,
I am noticing a gas smell coming through the vents. It happens only in the morning when I first start my car which sits outside overnight. It tends to dissipate after I get going for a few minutes. It seems to only happen after the car has been sitting for some time. On one occasion when I had it in a garage overnight there was a gas smell even outside of the vehicle before I started it and I checked for any leakage but there was nothing it was totally dry underneath the vehicle. Any thoughts as to what this may be? I've taken it to a shop but they couldn't replicate the issue. It doesn't happen every time but often occurs in the AM at first go. Any help is appreciated.
Thanks
I am noticing a gas smell coming through the vents. It happens only in the morning when I first start my car which sits outside overnight. It tends to dissipate after I get going for a few minutes. It seems to only happen after the car has been sitting for some time. On one occasion when I had it in a garage overnight there was a gas smell even outside of the vehicle before I started it and I checked for any leakage but there was nothing it was totally dry underneath the vehicle. Any thoughts as to what this may be? I've taken it to a shop but they couldn't replicate the issue. It doesn't happen every time but often occurs in the AM at first go. Any help is appreciated.
Thanks
Senior Member
Joined: May 2019
Posts: 431
Likes: 86
C400
Sounds like maybe some fuel left in the fuel rail or from a leaky injector, OR, a leaky evap valve somewhere
first thing I would do is use Lucas fuel injector cleaner and see if that helps. I had it unstick some injectors in my Skyline, I legit can't believe how well that stuff works.
first thing I would do is use Lucas fuel injector cleaner and see if that helps. I had it unstick some injectors in my Skyline, I legit can't believe how well that stuff works.
Super Member
Joined: Mar 2018
Posts: 740
Likes: 135
From: Westchester County, NY
‘15 C300 4M Sport, ‘20 GLC300
Senior Member
Joined: Feb 2018
Posts: 333
Likes: 102
2019 CLS450 (C257)
it's usually leaking at the high pressure hoses to the high pressure pump in the engine bay.
it can be as easy as changing out the hose clamps with new ones, or changing the hoses or even the high pressure pump.
Start with the clamps first, should be fairly cheap and easy to change.
it can be as easy as changing out the hose clamps with new ones, or changing the hoses or even the high pressure pump.
Start with the clamps first, should be fairly cheap and easy to change.
Member
Joined: Aug 2018
Posts: 158
Likes: 15
From: Spring, TX
2015 C300 Sport
I had it, but it was really strong in the garage.
I'd go out in the morning after the car sat over night, put a few things in before leaving for work & go back inside.
Leave for work ~10-15 min later & the whole garage smelled of fuel.
Svc adviser said it was a loose fuel hose under the hood. Whatever they did resolved the issue.
I'd go out in the morning after the car sat over night, put a few things in before leaving for work & go back inside.
Leave for work ~10-15 min later & the whole garage smelled of fuel.
Svc adviser said it was a loose fuel hose under the hood. Whatever they did resolved the issue.
Newbie
Joined: Apr 2019
Posts: 11
Likes: 8
C300 15
I've had this issue and it was just a hose replacement. Opposite end of the car vs our former W203 which had fuel leakage behind the rear seats! =P
Yet another reason we always go with CPO and some extra warranty padding.
Yet another reason we always go with CPO and some extra warranty padding.
