HI, I have a 86 gt . Since the weather has gotten cold here in new york i have put the heat on in my fiero when i take it out for sunday drives. I have noticed a anti freeze smell anytime i turn the heat on. If i shut it off and push the temp lever to the cold side i do not smell it anymore. I checked for antifreeze leaks inside and under the car i do not see any. And my anti freeze over flow still is the same level.Does anybody have any ideas I'm thinking its the heater core.I would appreciate if anybody had a similar issue if they can post what it might be .Thanks

quote Originally posted by Doms86gt: I'm thinking its the heater core.

Bingo.

If left long enough, you'll eventually get a pool of coolant forming in the passenger seat footwell.

Easy to replace. Good info in the forums regarding how to swap it out.

I just had this same issue with my 87. Antifreeze smell in the cabin when the heat is on, but no sign of it leaking anywhere around the car, and my overflow level was good. I turned out to have a small leak in the heater core that was enough to let the smell in without initially compromising the system. Unfortunately, I didn't realize this until the heater core fully let go on me during a drive around town and my temp gauge skyrocketed.

My advice would be to pull the cover under the passenger side of the dashboard and check for signs of a leak. Just make sure to remove your floor mats and lay down some plastic (a large garbage bag works fine). If it is leaking, you don't want to end up with antifreeze-soaked carpet. Mine dumped out quite a bit of fluid when I checked mine.

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"The Twins"
'87 GT 3.4 pushrod daily driver
'88 GT 3.4 DOHC swap in progress

Yep, heater core. Get it now while the leak is probably small. It's one of the easiest heater cores, for any vehicle, that you will ever change out.

Jim

Yup. An hour job at the most (and that's if you end up mopping up spilled coolant).

My leak ended up being right where the coolant tubes enter the heater core body. Even though I already had a new core purchased, my old man braised the crack in the tube while I was away at school so it was good as new. I suggest that you check to see if a small crack such as this could be the source of your leak as well. If so, you might just be able to save yourself $30 and just repair your current heater core.

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"The Twins"
'87 GT 3.4 pushrod daily driver
'88 GT 3.4 DOHC swap in progress

[This message has been edited by Irrationable (edited 12-15-2014).]

Be careful about running the blower fan with a heater core leak. Not certain how the vent setup is on these, but the fan could create a toxic mist of antifreeze coming through the cabin vents inside. Not good to breathe in.

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My Fiero: 1986 Pontiac Fiero GT, V6, 4-speed manual

One bolt for heater core removal is easy to get at when you remove the passenger side speaker if you have an AC equipped car.

This was one of the repairs I had to do on my 87 SE last year.
Windows started to fog up and had that unmistakable smell. I was initially hesitant to attempt a replacement, as I am a novice mechanic at best.
Purchased replacement from TFS and followed the great technical advice here on the forum and it all went smoothly.
The biggest PITA was getting the hoses off the old core.
Great step by step directions by member RWDPLZ in the FAQ's. & how to section.

https://www.fiero.nl/forum/Forum9/HTML/000009.html