ilikebig928butts

The tell tale signs of heater core troubles started popping up a week ago when the windshield fogs up whenever I park the car. (Just the bottom portion)
I read plenty about the heater valve replacement, but could not find one where I can sink my teeth in wrt heater core replacement.
I'm a freshman wrencher. I've messed around with all the electrical and peripheral bits. Is this something better left to the pro's? or I risk messing her up even more?

Rob Edwards

This is a king kong PITA but do-able. You'll need to pull the dash, pod, wheel, center console, defrost vents, and then remove the rear face of the HVAC box. The big unknown is how the footwell ducting is attached to the bottom of the HVAC box in an '84. There are 8 clips that hold the two halves of the HVAC box together, two of which are buried under the footwell ducting. If you can either remove the ducting completely (this cannot be done on an S4+ because of the airbag brain (and 10 other freaking things...) or unhook it from its front tabs and bend it down enough to get the two clips, then you're all good.

When pulling the heater core hoses, rig up some sort of drain hose on one side and blow compressed air through the other to drain the heater core itself.


EDIT: Are you sure the core is leaking? Does it smell sweet in the car? I'd make 100% sure you NEED to get into the dash before you actually do it....

outbackgeorgia

Agree with Rob, be SURE it is the heater core. Easily a bad heater hose leaking into the plenum that will cause the same symptom.
Dave

Podguy

I fixed mine on my vette with a can of stop leak.

ilikebig928butts

thanks for the heads up y'all. I'll start with investigating the hoses 1st. The next logical question is "where do I start poking?" Aren't the hoses also behind the dash/POD cluster?

Bill Ball

The hoses end at the firewall, in the cowl area under the AC expansion valve. Take off the thin plastic cover, if you still have it, and take a look. You might get lucky. These hoses can be a bit of fun to replace as the factory must have installed them before the expansion valve - in my car the clamps' screw ends were completely inaccessible.

Mongo

That is a rare occurrence. Don't really see too many heater core threads on Rennlist.

miekojarvi

Replaced my heater core last winter. Its not that bad but it takes a day or two. Its a good oportunity to change a cracked dash, vacuum hoses and acuators.