I have been taking out the interior in order to replace floor plans and seam seal the interior. I got to the fan box and took it off in order to make room for more "Tar Scraping" and realized the heater core was leaking anti freeze into the cabin from the lower right corner. Does anyone have any experience with finding leakes. Does the core just pop out? Should I get a new core or is ther a way to tighten conections etc.. to check leaks? I see the assembly in my manual. Just not sure how to proceed


Thanks, David

first check the heater core valve. it's usually first thing to go. not dramatic to change

I just replaced both my heater valve and core, and yes, the core pops out rather easily once you disconnect the heater hoses in the engine compartment and open the heater box.

I used air pressure (choked down with a regulator to about 15 psi) to check for leaks, and in my case both parts were bad. I was able to buy new ones with help from one of our trusty vendors without a problem. I leak-checked my new parts (as an assembly) before re-installation too, just to confirm that everything was good.

A couple bits of advice:
1. Since the new valves have a different departure angle from the original 124 parts, go ahead and buy the new replacement heater tube with the correct departure angle. It will save you a lot of grief during re-installation.
2. The bolts on my new core were slightly further apart than the holes in my new valve (go figure), so I had to oversize the holes in the valve to get the parts to fit up. No big deal, but an added step that I did not anticipate.
3. Be sure not to over-tighten the bolts when you install the tubes; just tighten them enough to ensure a good seal with the rubber gasket . These aren't structural parts, so a little torque goes a long way.

This obviously then makes for a good time to also sort out cooling system issues (the inevitable scope creep when working on a Spider, right?). I replaced all of my radiator/heater hoses, and I discovered the tube to my overflow bottle was plugged--a common problem on Spiders, apparently, and one that can cause grief when you go to burp the system at the end.

In boca al lupo.

thanks for the advice