Still chasing bugs in my son's '87, and I'm going to replace it and the O2
sensor.  It's got erratic high idle, stumbling when cold, and I think it's
running rich when warmed up.

Just wondering if there is a way to minimize coolant loss.

There are a lot of pipes into the T-stat housing, and I can't clamp them all
off.  And, does the O-ring tend to stay in the bore and need to be hooked
out, or will it come out with the old sender? I'm going to replace it.

I may just use this as an excuse to flush and replace the coolant if I'm
going to lose a lot anyway.

Thanks!

Stuart