Engine coolant leak

If you smell it inside, look for a puddle about a foot behind the right front tire and toward the middle of the car. That's where it would drip out of the air conditioning drain hose if the heater core was leaking.

You may need to use a cooling system pressure tester to pressurize the system, then look for a leak. As a last resort, you can add a small bottle of dye to the coolant, drive it a little, then use a black light to search for bright yellow stains, including the tail pipe.

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