Has anyone ever found a stainless replacement for the standard heater core found in 740/940's? Mine are 91 740 & 940 B230FT.
I've done everything I can as far as BB recommendations and they last 3-4 years. My rads last 6-7 years and they are exposed to the excessive salt splash of winter here.
I've changed 3 cores in 2 cars and am pigheadly looking to not do this again unless I get some type of core that is more robust.

I created a IRONTITE ceramic seal circulator to just run it through the core only. Leakrate went from holding 15psi to 18psi . No dicernable fluid loss now but I get the telltale whiff of coolant in the car. Probably just what's happened in the past which is a mini pinhole in the solder joint between the tank and the fintube section. 2 pinholes have occurred in the beefed up solder joint (I had them beef it up)of a rebuilt core. A cooling pressure test holds 18psi now but won't hold 20psi. Clamp off the hoses to the core and the leak gets less.

I've never run an electric fan just the engine driven one and the operating temperature is mid scale once warmed up no matter the season. I run 87ºC thermostats year round.

Stainless?
ian