I put my defroster on for the first time ever last week and I soon started smelling coolant slightly. The smell has persisted with the defroster off.
In the old days, your temperature adjuster operated a valve letting hot coolant flow through your heater core. In modern cars this valve is eliminated and interior temperature is regulated via airflow regulation.
I’m thinking that if Fieros have the old fashioned system, my valve may be leaking.
This morning was cool and dry and on the way to work I had no ventilation on at all. The windshield fogged up right over the defroster vents once the engine warmed up. Further, the car leaves no puddles and the coolant level has been dropping very slowly. Also the smell of coolant persists inside but I smell nothing outside.
It almost has to be the valve or the heater core.
Do Fieros have a coolant flow control valve and are they prone to leak?

Check to see if the carpet is damp on the passenger side (some times it's hard to tell).
Sorrey I dont know if it has the valve or not.But if you can smell coolant it's probubley leaking.

To answer your question -- no valve. Coolant always flows through the core and there's an air flap that regulates air flow across the coils. It sounds like your heater core needs to be replaced.

Thanks for the info DCsoundNut.
Your screen name makes me wonder if you are into battery powered amplifiers. Is that so?

Can someone tell me how to get to the heater core? Is it from the front front compartment or the dash side?

Does your car have AC, or not .... the procedure is different to replace the heater core depending on which it is.... If you have AC here is a great write up on replacing the heater core...


//www.fiero.nl/forum/Forum2/HTML/043997.html


Rich

Thanks for the Link Richjk21.
That’s great. I found the core in stock for $42.99 and those hose clamps will save some time if I don’t find the hoses in need of replacement.
I checked and my carpet is wet with coolant as expected.