floor board

[xvr843]

if a heater core is leaking could i smell antifreeze in the cabin?

[J Wikoff]

Yep, you could.

[Mad Myche]

...as the heater core is within the HVAC ducts, so the vapors can be pushed into the passenger cabin. I don't know the Bonneville ducting, but on my Cierra I would get coolant film on the windshield and it would also drip onto the carpeting

[xvr843]

i think my floor sweat, i see no sign of coolant loss

[Madcarpenter]

Take a look at your coolant overflow tank.

I had a coolant smell inside my wife's Bonneville only when it was warmed up to operating temperature, but no wet carpet, no coolant loss, and no leaky heater core. I started to worry about the plenum, LIM gaskets, plastic coolant elbows; the common problems with this engine...

While checking the level of the coolant overflow reservoir, I found a 1/8" wide, 2" long crack in the top of the tank near the neck. The smell of the warm coolant in the engine compartment was getting into the cabin through the fresh air intake. As soon as I replaced the reservoir tank, the smell disappeared.

[xvr843]

Thanks you guys quick update, wet carpet was coming from the rubber floormat(weird) when i remove the floormat, my floor was dry since and its been past 2 days now.

[MattStrike]

Yep. If you smell coolant inside, the carpet is damp at the front right, and the radiator/overflow tank is losing coolant than the heater core is likely leaking. Coolant has an odd, sweet odor.

The heater core is behind the glove box. Remove the cover under the dash on the passenger side, inspect for coolant on the foam, watch for coolant dripping.

If you are not loosing coolant, then the heater core is not leaking.

You might also be experiencing leaky door seals, making the carpet wet.