[sledge149]

A few days ago I paid to have my spark plugs changed in my 2015 BMW 328 (F30) and since then I have noticed a somewhat strong gas smell inside the cabin. The smell wasn't there before I paid to have the plugs changed, so I naturally thought that it had something to do with the spark plug change.

I took it back, they kept it for two days and said they smelt it, but after taking it apart and putting it back together, the smell went away. Well, I still smell it.

I just took all of the coils out and I found one coil that was slightly corroded, and one of the "shafts" the plug fits into looking similar in the area of the engine bay that I can smell gasoline. Sort of dark looking as opposed to bright and shiny and it SMELLS LIKE GAS. Im hoping you can see what I mean by looking at the pics.

So, what's going on? Did they break a plug while putting it in? (I don't have a socket to pull them out to check myself) And is this why I am smelling gas in the engine bay as well as the passenger cabin?

(Note. I dont drive with the engine cover off and the coil pack that is rusty looking is the second from the back of the engine)

[Wgosma]

Maybe plug is not sealing/seated correctly, some dirt,etc. or mechanical damage to the sealing ring surface...fuel leaking past

Need to pull plug and inspect seal and mating surface.

[Wires]

I'd have to saw whatever is causing that rusting isn't from a couple days ago, that's months ago. Is the car throwing any codes?

[frchdragon]

I think that there was a TSB from BMW regarding the rust on the coil, stating that it was acceptable and they don't need to be changed.

[NEWTRON]

Originally Posted by sledge149

A few days ago I paid to have my spark plugs changed in my 2015 BMW 328 (F30) and since then I have noticed a somewhat strong gas smell inside the cabin. The smell wasn't there before I paid to have the plugs changed, so I naturally thought that it had something to do with the spark plug change.

I took it back, they kept it for two days and said they smelt it, but after taking it apart and putting it back together, the smell went away. Well, I still smell it.

I just took all of the coils out and I found one coil that was slightly corroded, and one of the "shafts" the plug fits into looking similar in the area of the engine bay that I can smell gasoline. Sort of dark looking as opposed to bright and shiny and it SMELLS LIKE GAS. Im hoping you can see what I mean by looking at the pics.

So, what's going on? Did they break a plug while putting it in? (I don't have a socket to pull them out to check myself) And is this why I am smelling gas in the engine bay as well as the passenger cabin?

(Note. I dont drive with the engine cover off and the coil pack that is rusty looking is the second from the back of the engine)

theres rust on your fuel line/injector. It looks like you have a small fuel leak there. Put it back together and check if there's any fuel leaking from that line while its running.

[AMG KLR]

Originally Posted by NEWTRON

theres rust on your fuel line/injector. It looks like you have a small fuel leak there. Put it back together and check if there's any fuel leaking from that line while its running.

Good eye

[slegau]

Had exact saem problem in my 2015 BMW 328i. Has spark plugs changed, literally had gas fumes and exhaust coming into cabin through vents, vent intake is right near spark plugs.

Brought car back, they pulled out all coils and noticed one was corroded like yours, replaced it, and majority of smell is gone but definitely still something remaining, been driving like this a while now.

Have you had any further success into finding the cause?

[McGyv3r]

Coil and plug, rust or not, will not produce a gas smell.

However, there is a high pressure fuel line going to the injectors right next to the coil pack. There is also oil residue on the valve cover near the spark plug well. It's likely that there is a small fuel leak. The mechanic may have accidently caused a leak, or it could be a coincidence.

[helomech]

Just a thought-I can’t verify this since I’m not at home, but I would think the cabin air intake would draw from an area that would be sealed off from the engine bay, presumably from behind the panels that have to be removed to access the plugs, since this just started after you had that done. The engine bay is pretty well sealed up, so if you are getting engine bay fumes through your cabin vents, they may have installed that paneling incorrectly.
I would do a leak check with the engine beauty cover & sound insulation off, and if you don’t see any leaks, check that the paneling aft of the strut brace is all installed correctly. There are multiple pieces that join together back there.

[McGyv3r]

Originally Posted by helomech

Just a thought-I can’t verify this since I’m not at home, but I would think the cabin air intake would draw from an area that would be sealed off from the engine bay, presumably from behind the panels that have to be removed to access the plugs, since this just started after you had that done. The engine bay is pretty well sealed up, so if you are getting engine bay fumes through your cabin vents, they may have installed that paneling incorrectly.
I would do a leak check with the engine beauty cover & sound insulation off, and if you don’t see any leaks, check that the paneling aft of the strut brace is all installed correctly. There are multiple pieces that join together back there.

None of the covers or panels in the engine bay seal against air. The beauty cover is to reduce the ticking engine noises. The cabin air intake comes from below the windshield wipers. So any smells in the engine bay easily get sucked into the cabin.

[Billfitz]

Originally Posted by McGyv3r

Coil and plug, rust or not, will not produce a gas smell.

That. Coils and plugs conduct electricity, not fuel. Look at the fuel lines, rail and injectors as possible leak sources.

[helomech]

Originally Posted by McGyv3r

None of the covers or panels in the engine bay seal against air. The beauty cover is to reduce the ticking engine noises. The cabin air intake comes from below the windshield wipers. So any smells in the engine bay easily get sucked into the cabin.

Yeah, I know the beauty cover doesn't seal anything. I was referring to the panel that bolts down behind the strut tower brace that has to be removed to access the rear spark plugs & coils. That piece has a seal on it where it mates with the structure back there, and then there is the seal at the rear of the engine bay that follows the strut brace from fender to fender. When the hood is closed, that seal contacts the hood all the way across, which, along with the paneling between the engine bay and the firewall, isolates the engine bay. So then, between the engine bay and the firewall, with the hood closed and the panels/seal properly installed, there is an enclosure for cabin air to be drawn from (which includes the cabin air intake under the windshield wipers) that is separate from the engine bay. I'm thinking, if the OP doesn't have any leaks, something is up with that enclosure.

[slegau]

Originally Posted by NEWTRON

theres rust on your fuel line/injector. It looks like you have a small fuel leak there. Put it back together and check if there's any fuel leaking from that line while its running.

Where do you see this rust, not sure what to look for or what fuel injector looks like?