Hey my 2005 Chevy Monte Carlo LS has a strong gas oder whenever it idles or when the heat is turned on, now I was told upon purchase that there is a small exhaust leak, could this be the cause of the smell?

 

I would get to the bottom of this, sounds like you have an actual fuel leak, and then "Poof". Follow all your fuel lines, could be that a rear injector O-ring is failing, something close to the heater air intake. If anything have a shop search it out, if for some reason you can't find it, this could get ugly on a very hot day... poof poof poof

 

Would the small hole that was told to me be the cause? I have a catalyst converter code or O2 sensor.

 

Exhaust gas and Gas Fumes smell completely different. If you smell Gas you have a Fuel leak. Check your fuel lines against the fire wall under the Master Cylinder. The connection were they go from a solid line to plastic. The connector there wares out on the pressure line. Also check the plastic line the crosses over the engine to the fuel rail and the connector at the fuel rail. These are your greatest weak points.
I had a leak at the connector under the Master cylinder. The intake for your heat is right above that. So if the leak is there, that would explain the fuel smell I'm the car when your heat is on.
At any rate, you should have it checked out ASAP, because if it's over the engine it could start a Fire, then you baby goes "Up In Smoke!"

 

^Not necessarily.

Evap leaks smell like gas. So does running rich...

 

Good point John! I didn't think about that. The Evaps canister is in that same area! I've never had a Rich mix in a fuel injected engine but yeah, I remember in a carbonated engine the fuel small did get into the cabin! Nice catch!!!!!

 

Still haven't diagnosed the initial problem but I appreciate you guys, just fixed my actual exaust leak/shaky hanger. The gas smell isn't as bad but still present.

 

Probably evap. Is the engine light on?

 

My 2000 had a fuel leak at the rear fuel rail disconnect strong odor took a little longer cranking to start (low pressure) found a neat repair kit. Enter Malcolm Fay in search box read my post on fuel leak repair for details on the kit.

 

@02ssintimidator, engine light is on!