Hello, hope this hasn't been beat to death in some old thread. 02 F150, turn on heat and get a coolant smell in the cab. I have checked everywhere and there are no apparent leaks of the heater core. I disconnected heater hose and no smell, so it MUST be heater core right?????? Can the core be clogged and do this as well and is there a method to like blow out heater core, like low psi I air in one side to blow out possible restrictions, or is there somewhere else I should look?? Thanks

 

Bump, any ideas ??

 

You probably have a tiny leak - maybe just seepage somewhere in or around the heater core assembly. The logical place is at any connection.

When you turn the heater on, the fan blows across the leaked out coolant and you smell it until it evaporates.

If it goes away fairly quickly, you can probably just live with it. But, if you want to find it, you're going to have to locate the leak point. Until you can see all of the heater core, and any connections, you won't succeed.

I haven't looked for the valve that allows coolant to enter the core to provide heat. If it's behind the firewall, then that's a likely leak point.

I've had this in the past in a different vehicle, and it only happened the first time I used the heater after a long period of disuse. I just lived with it.

- Jack

 

Thanks, I disconnected one line to heater core and smell went away, guess it is time to do a heater core job, thanks again.

 

This might help