I bought my car back when I was in high school, and didn't have any money...
Sometimes, when the engine rpm's would 'zing', the heater core would find a weak link and start peeing all over the carpet. I tried soldering it a few times, and re-installing... but it wouldn't take too many more 'zings' to open up a new hole. I eventually broke down and bought a new one.
I also eventually bought a replacement heater/flapper box, as the original is cardboard paper, and mine was shot. The replacement was plastic. (Although, the outlets where the hoses fit were too small, so the duct hoses didn't fit very well. Hopefully, they've addressed the issue in the last 20 years. lol)
When I would do the job, I would just remove those clips, and split the thing with it still in the car. It's been a LONG time since I've had it apart, so I don't know which one of us is/was doing it the 'hard' way, or if there's really much of a difference. LOL!
One thing that can be done to avoid 'core busting' pressure spikes, is to put a restrictor in the core's inlet hose. Ford installed them in some cars right from the factory. These can be as simple as a 1/4" drive socket that fits the ID of the heater hose, and it can be held in place by a hose clamp. The restrictor allows plenty of coolant to pass through for heating, but guards against the pressure spikes brought on by high rpm. OH, the inlet hose is the one coming out of the intake manifold. A restrictor on the OUTLET hose would NOT be a good thing.
Nice article, Dennis!
Good Luck!
