It hasn't rained in a month, but the carpet in your Honda is soaking wet...what's going on? Well, it could be a couple of things but we'd put our money on a leaking Honda heater core. When it's working correctly, the Honda heater core does a great job of turning engine heat into cabin heat by flowing hot coolant through its tubes and passageways. But develop a pinhole leak (or worse) and you suddenly have green, sweet-smelling engine coolant flowing out of your Honda heater core and onto your dashboard and floors. With a little bit of luck, you'll notice the dampness from a Honda heater core leak before it can do any lasting damage to your interior. But, if you're like our friend who ignored the Honda heater core leak in his Civic for nearly a year (topping off the radiator on a daily basis), you'll find rust, moldy carpet, and a foul odor that's nearly impossible to get rid of is the result. So how do you know when you've got a Honda heater core leak? Moisture on the inside of the car is clue number one. It can come in the form of damp carpets, fog on the inside of your windshield, or simply a sense of high humidity in the cockpit at unusual times. Your first indication of a Honda heater core problem could come from an unexplained loss of coolant too. If you find yourself having to top off your radiator expansion tank frequently, but your engine has no visible leaks and doesn't show signs of coolant in the cylinders, the Honda heater core is suspect. Once you find a leaky Honda heater core, order your new Honda heater core from us immediately: The less time you live with a leaky Honda heater core, the better off your vehicle is going to be. Besides, a new Honda heater core, particularly when you buy it here, isn't that expensive. The weekend you're going to lose putting in your new Honda heater core...well, that's another story entirely.