Metal smell on cold start

[Rochev]

I have a 140k mile '16 Passat 1.8 and an 80k mile '17 Pathfinder 3.5. Both are cared for and not needing maintenance.

Let me start with this analogy: You know when someone pulls out in front of you and steps on it with a cold engine, and you can smell metal?

Yesterday I started my car when it was 60° out after sitting overnight when it got down to 26°. It smelled like burning metal pretty strong, something I've never noticed from it.
The next day I started my wife's car after sitting overnight with similar temperature ranges. It too made the same smell for a while and neither car has ever done that.

Now I am paranoid that there's a lubrication issue on both engines. Would you be worried?

 

[DriveHard]

Nope no worries - smelling the catalyst warming up.

 

[Silver]

Must be using that fancy "Titanium technology".

 

[Blinker]

I’ve never smelled metal coming from a cold engine’s exhaust.

Sounds like paranoia or your sense of smell has changed.

 

[Gyro Gearloose]

It's the catalyst bouquet. When I was growing up the smell was an eye watering, suffocating cloud of partially burned hydrocarbons with a hint of lead.

 

[repairman54]

Cold start rich mixture and a cold cat coming up to temp doing a partial burn off. Normal
After '60's and '70's cars and being a pump jockey in my youth back then with fillers behind the license plate modern cars are odorless.
I still like the unadulterated smell of leaded hydrocarbons when driving behind a ''classic''.

 

[Rochev]

Interesting. I've never smelled it before and haven't smelled it from either cars since. It reminded me of the smell of a dry engine creating a ton of friction.

 

[Snagglefoot]

Have you filled up lately? The winter formulation gasoline is out.

 

[Ihatetochangeoil]

I work in the welding industry and I have been next to blast furnaces and steel being smelted and poured. Metal doesn't "burn," it melts. Steel doesn't have a smell; but plenty of gases do, and some of them will kill you.
In a blast furnace, some hydro cyanide (HCN) and cyanogen gas (CN2) can also formed due to the reaction of nitrogen in the hot air blast and carbon of the coke. The reaction is catalyzed by the alkali oxides. These gases are highly poisonous. BF gas can contain these cyano compounds.
My guess is that you smelled the exhaust or the catalytic converter.

 

[Exhaustgases]

Metal doesn't "burn," it melts. Steel doesn't have a smell;

Pretty much anything that burns is being oxidized, steel burns when using a cutting torch that rapidly oxidizes it.
I've machined many different materials, yes steel does have its special smells when hot, everyone knows the rusty steel smell for one.

 

[Skippy722]

Pretty much anything that burns is being oxidized, steel burns when using a cutting torch that rapidly oxidizes it.
I've machined many different materials, yes steel does have its special smells when hot, everyone knows the rusty steel smell for one.

You can definitely tell when they went a bit heavy on the sulfur in 303 stainless. Cuts nice but stinks!

 

[Ihatetochangeoil]

Pretty much anything that burns is being oxidized, steel burns when using a cutting torch that rapidly oxidizes it.
I've machined many different materials, yes steel does have its special smells when hot, everyone knows the rusty steel smell for one.

Yes, you are correct, and so am I. You're not going to smell stainless, rust oxidizing, or any smells coming from machining, welding, or blast furnace gases coming from an automobile exhaust, even a mosquito fogger or a bad head gasket.

 

[KrisZ]

OP is probably smelling the exhaust fumes from a cold start. That would be my guess.

Also, if this “metal burning” smell was real, logic tells that it should be the strongest at full operating temperature, not during a cold start.