Dear Brickboarders,
I would be eternally grateful if someone with more knowledge/experience than me can shed some light on this problem. I have coolant on the drivers side in the mat and carpet yet it seems that the leak has stopped as the reservoir level is no longer dropping. A local mechanic tells me that this is a leak in the heater core, but I have read on this board somewhere that the problem may acutally be with O rings that seal the connections. Is this possible/probable? How difficult is it to replace the heater core, is it something that a relatively inexperienced (I do a few minor repairs) mechanic could do, and is it possible to determine whether is is the O rings vs the heater core itself. Thanks ahead of time

Whether it is just the o-rings or the heater core itself will not change the labour costs, which will be the majority of this repair if you are not doing this job yourself. If anything, the o-rings will take longer to do then the core.

In any case, if you want to take a whack at it, just get a FSM or a haynes or chiltons, and take a whack at it. After taking a look at the diagram, it shouldn't be too tough, just a long process that will require patience more then anything else.

I inspected the heater box and pipes into the core, externally, just by taking down the knee panel and the black piece of plastic. What I found was just a few drops of coolant when the on the bottom of the black plastic "clamp" that goes around the aluminum pipes as they enter the bottom muddy green plastic piece that is the bottom of the heater box itself. These drops of coolant stopped once the engine heated up. Does anyone think that this implicates the O rings (expanding and sealing better with heat) rather than the heater core.
Also does anyone know of a link to a discussion of dismantling the heater box and core, in the same vein as Bay 13? thanks in advance

Hi Dana,

I had the same problem with my 99XC. The leak was coming from the o-ring connection to the heater core. All you have to do is tighten up the screw that holds the black clamp on to the heater core and check for leaks. I stuffed the gap between the clamp and the floor with paper towels. After 2 months I have no leak.

Oh if the heater core was bad and leaking you would be getting coolant leaking from the heater core box. The heater core is mounted in a white plastic box that bolts to the bottom of the passenger cabin air manifold. If the heater core was leaking you would be getting coolant leaking from the seam where the heater core mount to the passenger cabin air manifold.

Also I removed the heater core in my car. I can never see a heater core leaking. Mine was built like a tank.

Good luck,

Steven---

Get a Hayness book cost $14 at any shop step by step you can do it...

Why don't you remove the core from the car, and test it for leaks?