I've got a 2005 4-cyl. Mazda 6 Sedan with 125k miles and still drives great. Noticed a slight radiator smell inside the car, usually just first thing upon startup. When oil is changed, they seem to add very little to the radiator. Probably time for a full flush anyway and perhaps new hoses all around, but worried it might be a hose to/from heater core? Any thoughts/experience anyone can relay on what to consider?

 

One thing to keep in mind is that the first generation 6 overflow tank sits about 18" from the fresh air inlet at the base of the windshield. You may have a problem, or you may simply be catching a whiff because of that vent. On the 6, the face-level vents are ones considered the actual outside are 'vent' setting. That's why you feel air through them even when the HVAC fan setting is off. I don't know if you shut-down everything before you shut-off the car each time, but make sure you do shut-off the HVAC, as well as make sure the outlet setting is not on the face level vents. At least for a few days. See if you still notice the smell.


It might even be time to consider a new radiator cap. Seal could be leaking on the old one.

 

Excellent points. I'll try it this weekend and go ahead and get a new cap. Many thanks for the info.