Heater Core Faulty ???

I have a '94 Grand Am GT V6 3.1L
When, and only when, the heater or defroster are used the drivers side floor becomes wet.

Does this indicate a leaking heater core and if so how hard is this to replace and are there any good instructions online anywhere for doing this job.

I was led to beleive that actually replacing a heater core is very easy but getting to it is very hard !!

Yes getting to it requires some disassembly.
Its the standing on your head that kills.

heres a link that might help.
Heater core removal (http://www.autozone.com/servlet/UiBroker?ForwardPage=/az/cds/en_us/0900823d/80/09/d1/7f/0900823d8009d17f.jsp)

If you hav any other question just hollar !

Many thanks for the reply.

I do have a couple of questions.....

1. Where abouts is the heater core in the '94 Grand Am. I was told that it was on the passengers side, but going by where the water is and the pics in the helpful link you posted it appears to be more under the steering column ?

2. The link mentions raising the vehicle and removing the rear lateral transaxle strut mount. I have no idea what that even is, let alone how to remove it ! lol
Are these steps neccessary ?
I'm assuming that the hoses to the heater core go in towards the bottom of the firewall ?

ITs located in the middle pretty much, maybe a little to the right. If you hav a console it'll hav to come out. And most of the kick panels on the lower dash.

If you can get to the hoses from top,
or below,
without removing that trans brace why remove it :thumbsup:

Pretty simple to replace this, just lots of BS do disassemble.

Hope that help'd !

I did mine, it was dark, I was outside and the mosquitoes were quite hungry that night. Remove the radio, glove box, lower dash trim on both driver's and passenger's side. Black box, right in the middle of the car, has 8 or 9 small torx screws holding it together. When you think you have all the screws out and the damn thing still doesn't want to come out, look for the one that is jammed waaaaaaaaaaaaaaaay in under the dash. The only way I found to get this one (((^)(*&)(*(*&*&^ screw out was to remove the entire box, hvac controls and all. I broke the bottom piece of the box, changed the heater core, put the box back in, pieced it together as best I could, glued it (and I mean GLUED it, full tube of gorilla glue), got home from work the next day and turned the sprinkler on, let it rain on the car while I checked for leaks. I got lucky, no leaks, but that one screw is a major pain to get to, unless someone has an easier way to get it out.

Ya those bottom ones are tricky to get to. :shakehead

When cars are made the whole HVAC unit is assembled before it goe into the car, as on most vehicles since the late 80's.
Damn engineers :angryfire :D

When you use your heater and the floor gets wet is it antifreeze or just water (taste test works great here )? If it is not antifreeze the heater case drain may be plugged with debris clean the drain and give it a shot. When you turn your heater on to defrost the air conditioner will run to take away the mosture in the air and do a better job of defrosting. It may save you some time by checking the case drain first.

just to add my :2cents: , I'd check the drain first ... like johnnyt43 said ... If its a heater core leak your windshield should fog up, & you will smell the sweat smell of antifreeze inside the car. The drain johnnyt43 is refering to is an elbow looking piece of rubber that comes into the engine compartment thru the firewall and points down with nothing attached the the bottom end, I think it has a slit in it that points to the ground, and if the box is full of water when you open it back up it should drain, so I wouldn't be under it when you open it up.

Thanks to you all for your replies ! :)

I was wondering whether it really IS the heater core. Last night I ran the heater for some time (get wet feet and be warm or dry feet and feeze!)

As was expected the drivers floor got wet through.

However, there is no smell of anti freeze, it feels like water, not oily and the coolant does not appear any lower even after the floor is wet.
The windshield doesn't fog up and to make things even stranger, not only does the drivers side floor get wet but back floor on the passengers side gets wet too !

How do I 'clean the drain' that has been spoken about. This sounds an easy option to try first than the heater core !

So on the leak, you do hav antifreeze in your car?

A bent stiff wire(such as a coat hanger) and a wet dry vac works great.

The drains on the firewall, on the passenger side toward the bottom.

Yes, there's antifreeze in the system but it doesn't seem to be antifreeze that leaks onto the floor.

Thanks for the directions of where to find this drain. I will have a good look for it tomorow.

Ok, I could be stupid, blind or both !!

From what I gather, the drain is located on the firewall, at the bottom, on the passenger side.

I tried looking from above, almost impossible to see down inside.
The side trim and height from the ground make it impossible to just crawl underneath and have a good look, so I looked as best I could from the side of the front wheel ( after locking full over and sticking me head under as far as it would go )

I still don't see this elusive drain anywhere!

Can someone help me out and tell me where to find it. From followup reading it sounds like this is what has been causing the problems.

Many thanks in advance.

I cant remember exactly but I thought the early GAs had a flat rubber gromet with a flap, thats hard to see.

I'll try and find A pic !!!

TO find the drain You must lift the car up and crawl under. Find the heater hoses going thru the firewall. Towards the passenger side of the car you will see a rubber 90 degree elbow, providing it is still on there. That is the heater case drain. Pull the rubber elbow off of the palstic piece from the case and see if the drain elbow is plugged if it is not than try to put a coat hanger thru the hole but be carefull, the heater core and evaporator are inside. Hope this helps

I couldnt find a pic of early 90's model GA drain.

It is there, and you will need to jack the car up to see.
Remember Safty first , Use Jack stands !

Many thanks to all that posted on this thread.....

I took the car tp a friend who has a shop and was able to lift the car and clean out the heater case drain.

No more water coming into the car from that moment on !! :)

After having wet feet for what seems like a lifetime it was like having a new car.