[BigJon10]

My wife has a 04 Murano SL 197,000 miles. When first started its puffs a cloud of white smoke and reeks of exhaust fumes.
Going down the road the smells slowly dissipates but when stopped at idle it returns. It’s very strong to the point I had to kill the engine and let windows down because my head was pounding. Anybody have any idea what could be causing this and how I could fix it

 

[MuranoSL2003]

Scan for OBD2 trouble codes.

But most importantly, inspect your exhaust systems for leaks ASAP. It sounds you have a very dangerous CO leak...

 

[Cryogenix1]

Despite my MO not having any serious exhaust leak, when I had an oil leak from the bank 1 valve cover that was dripping onto the exhaust system and creating smoke, anytime I'd use the heat and be stopped on a slight hill, smoke would start to enter the cabin and I'd have to roll down the windows to air it out. While in motion, it was never an issue. The heating system is drawing in outside air, which means anything wrong happening under the hood can instantly be brought into the cabin under those circumstances. Likewise, if the wind is not in your favor, a rich-running engine can create headache-inducing fumes if tailpipe exhaust fumes are being blown towards the front of the car and being drawn into the heating/blower system, particularly while the car is stopped.

Until you can figure it out, I'd bundle up, keep the heat at low on your feet only, and keep some windows slightly opened to allow fresh air in and carry bad air out.

 

[I need coffee]

It could actually be two problems based on the initial description. The "fumes" definitely sounds like an exhaust leak. Does the engine sound noticeably louder since this all started? If so, that's another symptom of an exhaust leak. I would suggest checking the exhaust manifolds for a crack (esp. bank 1 against the firewall) as that has been noted as a common problem on these forums for the 1st generation. Obviously, check the rest of the exhaust as well.

The cloud of "white smoke" sounds like you might have a head gasket issue as coolant entering the combustion chambers of the cylinders will produce a symptom like that.

 

[DreamCar5683]

My wife has a 04 Murano SL 197,000 miles. When first started its puffs a cloud of white smoke and reeks of exhaust fumes.
Going down the road the smells slowly dissipates but when stopped at idle it returns. It’s very strong to the point I had to kill the engine and let windows down because my head was pounding. Anybody have any idea what could be causing this and how I could fix it

When we had this issue years ago on our 2006 we had a cracked rear exhaust manifold. Hard to get at to actually see the crack.