I had my heater core bypassed for a while because the it was leaking, picked up a good used tested unit a while back (on ebay for $10), and been dreading installing it because of pass experience on 240's (240 heaters are very time consuming, not very difficult). Well, I started pulling it out yesterday, which took about 30-45 minutes to pull (I thought I had to take the hood, but it slide right out including the control valve very easy). I cracked it open, and the new core slide right in-> very nice!).

I had a new heater control valve for a 240 sitting around (they look almost identical to the 122's), and remembered some postings or IPD claiming that the 240 control valves can be used, which it can. I even used the control valve "sensitive" tubing from the control valve to under the heater core.

All-in-all, it took about 3 hours to do the whole job, and I goofed around the whole time. I bet most people could do it in half the time.

If anyone here is wondering how easy it is to replace the heater core, I would say it's pretty easy (on a scale of 10, 4-5)!

Paul