Although I finished freeing up the heat riser valve in May, I've (slowly) finished the other things up that I came across while getting it fixed. Removed the oil filter can to get to the flap rod, so I painted it and added new hoses, which entailed a new swivel fitting. Once again, I received a bad part from classic parts, which delayed finishing. I also replaced the old accelerator return spring and found the missing tab that it was suppose to be connected to. Pulled the new thermostat back off and started the truck up with it out, then checked it on the stove in a pan of hot boiling water. It opens at 180* as it should, so I put it back in.
In conclusion, after the thermostat was out, I took it around the block for a test spin, and it works fine. Put the thermostat back in, and drove it across town, and the temp is staying at 180*. I then drove it out to my diesel mechanic (I have an '04 Duramax 1 ton 4x4 I take there) to get it inspected, since it's plates expired August 2021, and brought it up to date legally. That was about a 10 mile ride and still no over heating problem. So, even though I hate to disagree with the folks who say this heat riser valve could not be the problem, I've found that it seems to be what the problem was. It didn't overheat until it stuck. Now that it's unstuck, it isn't overheating. I believe the heat riser valve was the culprit. Anyway, it seems to be running great, although I'm going to have to re-adjust to the noise level of the old bomb. After driving in the '04 for 2 years (first the bad timing gear and all the time it took to get it repaired, then the heat riser flap from sitting idle too long), I'd forgotten how loud it is to drive the '51. I'd also forgotten what it's like to drive with the windows down, the cowl vent open and the air conditioner (my vent windows open to aim the wind at me). Seems I'd forgotten how fun it was to drive, too. And the people who stop and stare when I go by. Something that NEVER happens in my '04. Thanks for ALL the help and opinions while I fought this thing. As slow as it went, and the headaches that came with it, all I have to do is think back to last summer when I changed out the king pins on this truck to realize that this was, in comparison, a piece of cake. And I didn't even split my thumb wide open like I did with that project. Twice. All is well.
