After neglecting a persistent coolant leak and discovering it resulted in a cracked head, I had no choice but to roll up my sleeves and get to work. The trusty '91 745 non-turbo now has a shiny new head and many other new parts such as tune-up kit, timing belt, intake hose, both sensors in the head, heater valve and hoses, flame damper, thermostat, and O2 sensor, plus a cleaned and adjusted throttle body.

It starts fast and runs smooth. The problem is that (1) the coolant leak is still there, and (2) it's lost a good 25% of the power it used to have!

Coolant seems to be coming from a passenger-side cowl drain. I'm thinking it might be the heater core but the evidence doesn't match anything I've read on heater core leaks, i.e., no water on the cabin floor, no vapor on the inside of the windshield. Any thoughts?

And as for the power loss, the computer has no codes and I don't know where else to look. A healthy B230F is slow enough, but this is ridiculous!

Thanks for your help!