The title says it all. Is there any other place from which the coolant could be leaking? I've searched the car and the forum and can't find any. All of the hoses are on tight with no leaks. The new core came from Napa. I didn't force anything. I may just order a new delco unit. I hate having to do things twice because of crapy replacement parts! Any insight is appreciated.

 

Where is it leaking and are you sure it isn't fluid from your old HC that's leaking, as a leftover if you will?

 

It's leaking onto the passenger side floor, the usual spot. I am almost positive that it isn't residual fluid. I flushed out the old core with a hose before removal to avoid spilling antifreeze in the car. I also cleaned up the heater box before installing the new core.
The old core broke at the end of last winter and I have put off replacement until now. I've been driving with the old core all summer with no drips or leaks (No flow through the core).

 

if its leaking inside the car its gotta be the core. maybe defective or got cracked as u were putting it in. pretty sure if the hoses were not tight enough, it would leak outside not inside. since the metal tubes extend thru the firewall.

like was said be absolutely sure its not old coolant first.

 

Those are my thoughts too. I'll double check for any leftover coolant. I hope I didn't crack it. I was treating it like a feather when I installed it.

 

ye, pretty sure that's all it could be. I would double check those connections though. Maybe run new hoses. When they leak at that connection that's where the water goes.

Easy way to make sure, turn your compressor down to 20 psi and put your thumb over the one end and the compressor hose on the other. You'll see where the leak is.

 

I got fluid inside my car from the outside.
The heater hoses weren't tight enough.
I tightened those bad boys, and it was fixed!
But yes, you can get it inside the car from the engine bay.

 

We install Napa heater cores at work. I check every one I put in. I've found several over the years with holes right out of the box.

 

Ac delco heater box all the way. I've checked two one from pep boyz and the other from autozone and they both had fins cracked. I swear I was depressed and they keep telling me that thats how they are.
So I went and got and AC delco one, and it was a beuty. Replaced it and no problem.

However, make sure you tightened the hoses on the box good and tight. Than make sure you routed them right too. From there, acutally pull the carpet out and run the car. See if its leaking from the heater core, or its just old coolant.

If its leaking return it back cuz I am sure you got a warranty with it.
Than get AC delco.

 

I think you've already done this, but make sure to replace those quick clamps (the ones you take off with pliers by squeezing them) on the heater core hoses with worm-gear clamps. I replaced a heater core only to find out it was leaking from those connections and going into the cabin..

 

Well, I've been using the heater in the morning for the past week and there has been no evidence of a leak. I guess it was some fluid that got spilled when the old core was replaced. I have worm gear clamps installed. Thanks for the input, advice, etc.

 

I now have to take the last comment back. I have been smelling and loosing coolant for the past 3 or 4 weeks but found no sign of a leak. A few days ago I noticed a few drips under the car so I lifted the passenger side matt and there was a pudle. So I'm going to do the job for the second time and hopefuly the second new core isn't crap. I'll get an autozone cheepo this time; maybe it will be better than the Napa part.

 

Anything I don't want to do twice I go to CarQuest for parts - they are more, but the cash outlay is far less a problem than the headache.

 

As with just about everything Napa sells 2 different lines of heater cores. Theres the elcheapo and the notso cheap. And of course everybody gets bad parts at some time.

 

Well I got the new one in. For those who are interested, the Autozone core is physicaly identical to the one from Napa. It is just packaged in a different box. So save a few bucks and go to Autozone.
I'm going to have to give it a week or two of use before I decide everything is OK but so far so good.
Another piece of plastic on the plastic car broke. I am not going to buy another car that is not pre-emissions. There is just too much plastic junk. I like the looks of the third gen but when that plastic gets old it takes nothing to start a crack or break it. It would make a nice race car after its been stripped down though!