[jcp123]

I haven’t taken a look at the heater box in mine. Hondas have a reputation for being easy to work on (which I can largely verify), but something tells me packaging will be an issue. IIRC doing this in a couple classic Mustangs, it was about a four-hour job, but granted, there was hella easy access. I’d at least double it in your Civic.

I definitely would avoid junkyard heater cores - they will probably have worse problems than whatever yours has. Having worked at Autozone, though, I’d be dishonest if I said Spectra made great products. They were fairly high-return items for us, both the radiators and the heater cores.

I wish I knew where to source something better. Maybe the Honda aftermarket scene has something? Or you could pursue it the way I pursued my oxygen sensor, see if an OE supplier still makes it by a different name/part number. My NTK (NTK is NGK’s OE supplier division) oxygen sensor IS, for all intents and purposes, a dealer O2 sensor, since they were the OE supplier for those to begin with. But! for something like 1/3 of the price. Took a couple of days to chase down the OE supplier and part number, but I think it was worth it.