A week ago I started my '88 (V6) for the first time in about 18 mo. ... it was running very rough, low power, some backfiring but was able to drive it around residential streets w/o much problem and got engine temps up to around 220. Brought it back got some Lucas fuel injector treatment and warmed up the engine in the driveway. For kicks I tried out the A/C and after running the A/C for a while during the engine warmup in the driveway I noticed a leak in the passenger compartment under the heater core (probably a bad heater core)... ok so I got that on my list of things to fix

I checked the garage floor (I store it inside during the new england winters) and didn't find ANY pool/puddle of leaking fluid. I put a tin can under the leak in the car to catch it so it wouldn't get in the floor mat too much. The next day I checked on the can and it was about 1/3 full (4oz) of the bright day-glow green anti-freeze fluid.

A few days later I drove it around again to see if the engine was running any better and it was a bit, this time I didn't run the A/C and the leak was barely noticible.

Today, a wanted to give the engine a good warm up so I backed it out the garage and ran it around 3500rpm until the temp hit 220 and the battery gauge jumped (I think to indicate the front fan turned on). The temperature sat at 220 for a few minutes before I decided to drive it back in the garage.

This afternoon I decided to just check on the anti-freeze levels to see what they were.... to my astonishment when I removed the coolant resivior cap (when the car was cool, it had sat for about 6 hours) I couldn't SEE ANY coolant....

The repair shop I'm going to take this to for the heater core is about a 5-10 mile drive (not too far) and I'd hate to have a tow to get there... should I just fill it up with anti-freeze and drive there? (Or would the fact that it's drastically low already be a good reason to tow it so no damage results to the engine/radiator)

Does anti-freeze evaporate? I mean I didn't see ANY pooling at all in the garage... bone dry.

Thanks,
Steve

quote Originally posted by buhockey56789: A week ago I started my '88 (V6) for the first time in about 18 mo. ... I noticed a leak in the passenger compartment under the heater core (probably a bad heater core)....

And your heater core may have been slowly leaking for who knows how long while your Fiero was sitting for the last year and a half.

quote Originally posted by buhockey56789: This afternoon I decided to just check on the anti-freeze levels to see what they were.... to my astonishment when I removed the coolant resivior cap (when the car was cool, it had sat for about 6 hours) I couldn't SEE ANY coolant....

You've no doubt complicated things a bit by allowing air to get sucked into the coolant system. Not a big deal, but before you drive to the shop to have your heater core replaced (you should actually do it yourself, not difficult), you'll need to properly burp the system while adding water. When the heater core is replaced, it would be a good time to flush the system and fill with with fresh coolant.

Next time, check your fluid levels before you start a car which has been sitting for a long time!

[This message has been edited by Patrick (edited 06-15-2014).]

Replacing the heater core is very easy. Remove 2 hoses in the front trunk connecting to the heater core; remove (4) 7mm screws holding the heater box cover in the passenger footwell screws are at 12 o'clock, 3 o'clock, 6 o'clock and 9 o'clock positions as you look at the face of the heater core; remove 7mm screws holding the heater core.

If you don't wanna try it, I'd just top off your system and go the 5 - 10 miles. watch the temp. gauge.

After the core is replaced, I'd do my cooling system maintenance.

Replacing the Heater Core yourself is not too complicated, although if it weren't for this article, I also was going to take it to a shop to have it done.

Being that I hadn't really turned a wrench in many years, I was hesitant at first, but decided, what is the worst that can happen?

This was first real repair I did after acquiring my Fiero, and while it took me a lot longer than someone more proficient than I, it turned out great. And I had the satisfaction of doing it myself.

If you decide to attempt it yourself, go to this link.

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

I'll second what everyone else is saying about the heater core. It is easy to replace. I just did my sons yesterday. Took an hour start to finish. Burping the system is harder than replacing the core itself.

Jim

Thanks all .... after reading the articles (posts) here on replacing the heater core (w/ AC) I think I'll move ahead and give it a crack. (I've got the A/C heater core on order from FieroStore)

Something that is concerning me is the coolant fluid draining. Because that needs to be done prior to detaching the heater core. How difficult is that? I don't have any large car jacks or anything (outside of the flat repair jack to give me more room under the car than would be normally) Is this an issue? Anyone have any ideas of what kinds of things that could be used as a catch basin (ideally that could be sealed up for disposal) but would also fit under the car without jacking the car up?

Thanks for all the help!!

I think I found some low profile oil/coolant collection pans at autozone.. these will probably do any suggestion on good quality brands?

[This message has been edited by buhockey56789 (edited 06-16-2014).]

quote Originally posted by buhockey56789: Thanks all .... after reading the articles (posts) here on replacing the heater core (w/ AC) I think I'll move ahead and give it a crack. (I've got the A/C heater core on order from FieroStore) Something that is concerning me is the coolant fluid draining. Because that needs to be done prior to detaching the heater core. How difficult is that? I don't have any large car jacks or anything (outside of the flat repair jack to give me more room under the car than would be normally) Is this an issue? Anyone have any ideas of what kinds of things that could be used as a catch basin (ideally that could be sealed up for disposal) but would also fit under the car without jacking the car up? Thanks for all the help!! I think I found some low profile oil/coolant collection pans at autozone.. these will probably do any suggestion on good quality brands?

Don't make this job harder than it is . I think there is a drain petcock on the bottom of the radiator on the passenger's side but I just pulled off the lower radiator hose when i did mine. There are only 2 things i'd recommend that you watch out for:

1. don't bend the tubes or damage the heater core when you push on the hoses in the front trunk
2. don't try to over-tighten the screws in the passenger's foot well - you are putting metal screws into plastic and they will strip the plastic if you try to get too tight.

The careful part comes when you re-fill the coolant system and get all the air out.

While you're at the parts store, get some windex and paper towels and wipe out the inside of all the ventilation ducting when you have the heater core out .

[This message has been edited by PaulJK (edited 06-16-2014).]

quote Originally posted by buhockey56789: Does anti-freeze evaporate? I mean I didn't see ANY pooling at all in the garage... bone dry. Thanks, Steve

yes it can evaporate if your radiator cap dont hold the pressure the radiator cap is the most parts that many dont check it it have two function hold pressure to raise the boiling temperature and have a vacuum valve . when the coolant are cold it retracs and let air entering the systems to not break your coolant hose over time so if your radiator cap are not holding pressure it will probably boil and you will loose some coolant due to boiling evaporation

quote Originally posted by buhockey56789: Does anti-freeze evaporate? I mean I didn't see ANY pooling at all in the garage... bone dry.

When your heater core leaks, it doesn't drip on the garage floor!

I had the same issue with a Fiero which had been sitting for a long time. Upon closer inspection, I discovered that the under-pad of the passenger side carpet had become a giant sponge and had absorbed a considerable amount of coolant from a leaking heater core over a period of many months.