BikerBill

My heater core has developed a moderate leak. I made a bypass for it with PVC pipe and fittings so I'm not dribbling antifreeze all over the roads. I've done some checking and let's just say replacing the core looks like a fair piece of work. I'm wondering if it's worth trying to fix it with one of the various stop leak products. I'm reluctant to have that stuff runnning through my engine and cooling system. So I was thinking of just adding it to boiling water and adding the water/stop leak mixture directly into the heater core. I could pressurize the heater core if needed. I could also pull the heater/AC fan, stick a hairdryer in the heater box, and heat the heater core to activate the stop leak. Then I'd drain the stop leak solution, flush the heater core, reconnect it, and top off with water and anitfreeze.

Has anyone tried something like this? What was your experience? What stop leak product did you use? If there is a reasonable chance this will work I may give it a go.

4Driver4

I'd say no. Even if you can plug it up and still get heat out, that crap will eventually find it's way to the engine. Just bite the bullet and do it.
Hey, look on the bright side: the part is only $39! LOL

You should be.

mtroxel

Ditto. I bought a 01 Avant last winter that had that stuff in it. You have no idea what a mess it made in the motor/radiator.

I've done the heater core/dashboard job on two B5's. It's not hero mechanics. It's just time consuming work. But like everything else in life, it's no big deal if you just stop talking about it and do it.

turbo510

Isn't that the truth!

1999Audi

It took me two days without rush.
And you dont have to remove aluminum frame completely from the car just move away as far as possible(just disconnect 4connectors at ecu box) and pull the heater core.

Its gonna look like this:

<img src='http://img849.imageshack.us/img849/5281/img9357wires.jpg' border='0'/>

mtroxel

That's how I did it both times, just move the frame enough to get access to the heater box. As long as you're there, you'll have to purge the AC system. Might as well do the evaporator too. When that leaks, you've got no AC till you do that whole job again.

4Driver4

My heater core was fine. I had to replace the leaking evaporator core. $400 dealer only.

mtroxel

Really? What's wrong with this for $107?

moloveshisaudi1254

Do all B5's require the A/C purge to replace heater core or only certain years?? And what is the procedure for the A/C purge?

4Driver4

Not available from my trusted parts source. For something buried so deeply in the dash, I won't go with a vendor I don't know.

BTW, the part in the picture is not the right core.