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Sweet-smelling substance in my car


When I put on the cold air in my 2003 Mitsubishi Galant, after it’s on for a while, I start smelling something sweet like syrup. I haven’t noticed it when the air’s not on and I don’t know how long it’s been happening because my sister’s been using my car since 2008. It seems to be coming from the front, but I’m not really sure.

Does anyone know what this is (is it coolant?), is it dangerous, and how much it should be to fix?



This is very likely a heater core leak. You don’t want to breathe coolant, so you should get this fixed soon. The price can vary quite a bit depending on the car; unfortunately, on many cars quite a bit of labor is needed to get to the heater core.

Yup, sounds like a coolant leak. Check under the hood for leaks in the radiator, hoses,and intake manifold. The leaks may be easier to find if you are under the car and looking up. Check your antifreeze level by removing the radiator cap when the engine is cold and top it off. Then stick your head under the dash and look for moisture, you could have a leaking heater core. This could be dangerous…to your engine and it overheats. The costs could be dirt cheap or very expensive. A lose hose clamp would be free, while a leaking heater core is not. Good luck.

I agree. The most likely source of the smell is a coolant leak, possibly in the heater core.

Check the coolant level in the radiator. Are you slowly losing coolant?

Breathing coolant fumes is extremely unhealthy. You should have this checked out ASAP.

It’s possible the smell is coming from some other source, but coolant has a sweet, syrupy smell, exactly as you describe.

If the windshield fogs up when you turn the defrosters on, it’s definitely a heater core leak. I’ve had 3 of theose, 2 on Fords and one on a Chevy Impala.

The cost varies greatly; some have 8 hours labor (Ford Granada with air) to replace since the dash has to be dismantled. Others, like the rear drive Chevy take only $125 or so to replace.

Thank you all for the responses. It looks like it is rather urgent. I will see about it right away.

Thanks again,