Fumes entering cab (sometimes)

ktmmike

2014 Sport Package 370Z Coupe

Sometimes after driving for a while with the heater on, I can smell some sort of fumes in the cab.
NOT exhaust fumes.
Smells more like oil breather fumes possibly??? Not completely sure.

Intermittent. Some days I can smell it on a short drive (or not).
Other days I can take a long trip and not smell it AT ALL.

Never smelled it in the summertime with or without A/C.
Seems to happen only when heater is on (and even then, only sometimes).

When I smell it in the cab, I can stop, lift the hood, and smell NOTHING anywhere under the hood.

No exhaust leaks.
Checked entire engine for any kind of oil seepage onto hot engine surfaces.
None. Perfectly clean.

QUESTIONS:
1. Has anyone experienced this?
2. Is there an existing thread on this problem?



Thanx for any help,
Mike




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3 KTM SUPERMOTOS & a 2014 370Z

SouthArk370Z

Sounds like there is something in the heaters ducts or you have a leak in the heater core. Does it make any difference if you switch from recirc to outside air mode?

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ktmmike

Thanx SouthArk,
I will check both air modes tomorrow and see if there is a difference.
Please stay tuned.



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3 KTM SUPERMOTOS & a 2014 370Z

SouthArk370Z

Have you changed the cabin air filter lately? In heat mode, the system defaults to pulling air from outside, through the filter. In A/C mode, it recircs cabin air and doesn't go through the filter. Both modes are probably a blend but the majority will come from one source or the other.

Edit: It might help to look through the section on HVAC in the FSM.

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Zipper 104

If the heater core has a leak you ought to see coolant on the inside of the windshield on the 'defrost' setting.

104

SouthArk370Z

Good point.

Maybe "seep" would have been a better word to use. Just enough to cause a smell but not enough to start fogging things up.

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ktmmike

I don't think this smells like coolant, Southark.

I know I can smell it in outside air mode, but I can't get out today to see if I can smell it on recirc.

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ktmmike

Inside of windshield absolutely clean, no coolant on it.

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3 KTM SUPERMOTOS & a 2014 370Z

glw

does it smell like burnt oil? after hard acceleration?

ktmmike

Yes, glw, it could be a burnt oil smell . . .
and yes, now that you mention it, the smell seems to be at its worst:

1. after hard acceleration UP steep twisty mountain roads (which is mostly what roads we have around here). AND

2. also at its worst at relatively higher rpm in lower gears while running back down the steep twisty mountain roads.

I can cruise down the Interstate at 80 mph for hours and not smell it at all.

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3 KTM SUPERMOTOS & a 2014 370Z

SouthArk370Z

That sounds like you are overloading the cats. Mine did the same thing on hard acceleration.

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ktmmike

Overloading the cat(alitic converters)? with what? oil or oil fumes?

And how did you correct it?

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3 KTM SUPERMOTOS & a 2014 370Z

SouthArk370Z

Products of incomplete combustion. The engine is putting out more PICs than the catalytic convertors can handle.

I learned to live with it. A tune might help but I doubt it would eliminate the problem. "Better" cats might help but that sounds restrictive and expensive.

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glw

I, too, have the burnt oil smell post hard acceleration (with recirculate on?). It seems fairly common on newer cars (non-Nissan, too).

My guess is that the EGR PCV valve is passing too much oil to the intake on hard acceleration and we're smelling the resultant burn. I was looking for a place to mount one an oil catch can to see if it helps, but there's no room in the stock engine bay.

SouthArk370Z

I had always assumed it was over-fueling but EGR/oil makes sense, too. Wouldn't take much to make a big smell.

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Mankind has progressed past the need for war but we haven't evolved that far. - NachoMahma