Smell of petrol cold start W212 E250

[cheapshots]

Hi all,

W212 Facelift 2.0 E250 SE, 2013, 45k

For a week I've noticed a strong smell of petrol with a cold-start (first thing in the morning). The smell is coming from the engine bay. If I'm inside the cabin with the heater fan off, I can't smell the petrol, if the heater fan is on, I can smell the petrol.

The smell disappears after about 2 mins of driving and doesn't return until the next cold start (next day in the morning).

I can't see any visible signs of a leak under the car, and even if it was a leak, surely the smell of petrol would be constant?

Any idea's?

Thank you

 

[cheapshots]

Any ideas at all ?

 

[John Laidlaw]

Exhaust manifold gasket potentially

 

[LostKiwi]

Or exhaust leak anywhere under the bonnet.
You aren't starting it in the garage are you?

 

[cheapshots]

It’s only from a cold start. The smell comes from the engine bay.

And the car is parked on an open road.

I’m inclined to think it’s a small fuel leak somewhere and that’s why I only smell it from an overnight cold start...

 

[John Laidlaw]

The cold start made me think exhaust manifold, when hot it may be expanding enough to push the gasket tight again

 

[cheapshots]

Ahhh i see, makes sense.

I guess I need to visit my garage

I’ve been kidding myself that the smell is normal!

 

[cheapshots]

Booked into my local garage on Friday, will let you know what they find. I really hope it's something minor, 6 years old car with 44k mileage grrrrrrrrrr

 

[cheapshots]

Small update:

I usually use a fuel additive (Archoil AR6200) however, with my latest fill up, I didn't use this additive and there was no petrol smell during my morning cold-start.

Hmmmmmm,.... may be a coincidence so will keep my Friday appointment with the garage for now!

 

[John Laidlaw]

Small update:

I usually use a fuel additive (Archoil AR6200) however, with my latest fill up, I didn't use this additive and there was no petrol smell during my morning cold-start.

Hmmmmmm,.... may be a coincidence so will keep my Friday appointment with the garage for now!

Why are you using this additive....??

 

[cheapshots]

I got sucked into the hype around fuel additives a while ago and it has stuck ever since.

Things like this article made me initially use it

 

[LostKiwi]

Nothing like a bit of pseudo science to help market something....

 

[John Laidlaw]

As you probably guessed I’m somewhat dubious of the claims made, “snake oil” comes to mind, however that’s me really. If it works for you in some way why not?

 

[cheapshots]

With long term use the cars I've used it in had better MPG (1-2%) but other than that I haven't noticed much else.

 

[John Laidlaw]

I got sucked into the hype around fuel additives a while ago and it has stuck ever since.

Things like this article made me initially use it

OK, I fell for it and read it!
The phrases...
“This is achieved by increasing the surface area of droplets” and “The fuel becomes more aromatic (a sign of increased chemical stability)” crack me up...more power to his elbow there. I’m guessing the author is commercially involved in Archoil ?

 

[LostKiwi]

OK, I fell for it and read it!
The phrases...
“This is achieved by increasing the surface area of droplets” and “The fuel becomes more aromatic (a sign of increased chemical stability)” crack me up...more power to his elbow there. I’m guessing the author is commercially involved in Archoil ?

I liked the bit about lowering the flashpoint....
(flashpoint is a chemical property defined as the minimum temperature at which the vapour will support combustion - which for petrol is -45C!)

 

[cheapshots]

Ok I'll stop using the Archoil stuff

The smell of petrol is much less this morning, so I will cancel tomorrow's garage app and keep an eye on it. Odd.

On a side note, do you think my cat might be a bit dirty/clogged up? If so, what are your thoughts on Cataclean ?