malheur

Hello.

My 350z overheated about a year ago and had to rebuilt the engine.

When it's overheated, actually even driver side's cabin carpet(cheap aftermarket one) was melted. It is right above the catalytic converter, so I guess catalytic converter also very hot back then. I'm not sure if cat could survive on that hot.

So after engine rebuilt I have no problem for driving, but exhaust smell is bed. Some gas smell - sure, but SOUR like vinegar or acid.

1. No visible exhaust fume.

2. No smell at all inside cabin, A/C or engine bay. Only exists in exhaust.

3. No check engine light or error code. (This is why my mechanic said it's fine)

4. It's dual out exhaust(*pic), and only passenger side of muffler has that sour smell. driver side is fine.


In my mind, since cats overheated too, first guess was broken cats. But if cats are gone, there shouldn't be check engine light?

And on google, there could be coolant leak, but coolant is not decreased in both radiator and reservoir tank, and it's still clean green with no oil in it.

So... where / how should I check for sure? Is it cats? Are after-cat components like resonator or mid-pipe something can makes smell bed?

icer5160

iTrader: (4)

Brand new exhaust systems can have weird odors/smells thanks to the cutting grease and other compounds used while machining/welding/polishing the steel. If you have a brand new catback exhaust system, this could be perfectly normal. Based on your description of the overheat, I suspect one of your cats is fried and the exhaust has plenty of miles on it. The only way to be sure is to pull the cat out to inspect it (not that difficult). A cat code won't be throne for a while, it could take over 100 miles of driving under varying conditions before the ECU throws a CEL for the cat.
-Icer

mr. sparco

iTrader: (13)

If it smells sour like sulfur or rotten eggs, your catalytic converters are failing and will make that distinct odor. You can totally smell it out the exhaust after parking the car especially after making a hard pull.

MicVelo

Maybe the engine just had beans for dinner.

Spike100

Coolant leaking into the engine (warped head gasket) will smell like this.

malheur

Thank you guys. I believe cats could not be normal either, but based on the smell(it's not sulfur smell. definitely vinegar) and search, it should be coolant leak. Though weirdly coolant level is not decreasing and does not contain any oil...

Spike100

You will notice overheating if the coolant is leaking into the engine. If you are not seeing overheating, it must be something other than a coolant leak.