From time to time I get a pretty noticeable honey-like aroma coming out of my vents. Although it smells like honey to me, a friend described it as "old lady lavender".

I have a 2011 Nissan Sentra with approximately 45k miles.

I had the dealer perform an inspection, which included the cooling/radiator system. They did find and replace a cracked axle boot, but the smell persists.

The smell is intermittent and I cannot reliably reproduce. Sometimes it occurs from a cold-start, other times I won't notice it until I'be been driving for 20 minutes. It doesn't seem to be related to the air temperature or if the AC is on or not.

Should I have someone else inspect the radiator? What are other things that I should have inspected as possible culprits?


  • 3
    You said they looked at the radiator and cooling system, but did they specifically look at the heater core?
    – Compro01
    Apr 7, 2013 at 18:55
  • Not to my knowledge. It makes sense to me to look at that. I'll see if I can have that done and respond back. Thanks. Apr 7, 2013 at 20:46
  • I just had this inspected by the dealer. They claim that they pressure-checked the coolant system and could not detect any leak. Additionally, there are rodent droppings in the engine compartment. They suggest that there may be a rodent nesting next to the heater core and that the smell I've been noticing is evaporated rat urine. Before I have my dash torn apart for close to a grand, does this sound reasonable to anyone? Apr 26, 2013 at 18:18

1 Answer 1


You may have a heater core leak. A few drops blown into the vents will be aromatic and give a sweet-is smell. Telltale signs is moisture or staining on the passenger carpet, although a slight leak may not be visible. Sometimes a very difficult repair and other times not. Depends on the car. Google will know.

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