@AuroraGirl thanks for the feedback - any thoughts on where you'd suggest picking up a replacement?
No, haven't added a return line yet... wanted to initially try to solve the root problem, which is heat I think (combination of things actually) however, it is very high on my list to add a return line mechanical pump and return-line sending unit.
Exhaust is stock manifolds.
Coolant is approx 50/50 and new from changing the water pump and then changing the harmonic balancer...
The core of the problem is you have gasoline that inherently is more volatile snd less thermally stable at the same temps as the gas the truck was originally using which was itself problematic from day one.
3969837 Is a gm part number for a Quadrajet
9266 for edelbrock
If you want to test our recommendations against your deeply held ideas, put a spacer in that breaks 1) the conductive energy transfer with a material that doesn’t transfer thermal energy well between the carb and engine, then use a heat shield to baffle radiant energy from going toward it so easily, then wrap your fuel line and pump best you can with insulation for heat (home improvement store would have something) amd then try driving around in this same weather.
you will show some improvement if you out your stat back in.
on the t stat, the coolant water pump is damn good at circulation especially with a smaller pulley size (can we see your crank pulley and water pump pulley relationship too) name if it’s new, it’s probably high flow just from less wear. The coolant itself is kinda ****** at the heat transfer thing because of the alcohol. The reason we use it obviously is the cold protection and the additive packages for our cooling system.
but because it can’t transfer as well, it needs to be held in the side with hot stuff, an engine, to take that heat, then it gets cycled over to the radiator, where it hangs out giving its energy to the large surface area and air flow, and over to the heater core too even with no fan it’s sharing energy. If it flowed right past it wouldn’t release much or pick up. ESPECIALLY In cast iron,steel. And brass radiators. Brass is less thermally efficient as aluminum radiators I believe due to the need to solder which is usually tin or lead which isn’t as good, reducing efficiency, and the size of fins, walls, etc are usually thicker which makes for repair easy parts but not cutting edge efficiency.
My park avenue, for example, had no stat for a 2 day period while I was flushing system with thermocure. It ran cold as **** despite being September and rather warm because the engine when not in boost has such a low compression ratio and a large radiator, aluminum, 2 cooling fans, and at this point the inside was much cleaner too, which has a aluminum manifold and etc. it actually runs cold in winter by this nature and I have to block the radiator some amd if it was a really hot summer, I would have a 180 stat which is for reducing knock retard and reducing the overall temps because swampy weather and my affinity for induction noise WILL result in the computer taking your timing back real hard to prevent “chipped pistons” and “spun rod bearings” or “installing new drain locations” in the block. Which it over compensated fr, but not without some reason. That’s an example of 180. 180 becomes 195 when it’s temperate or cold. For efficiency, economy, plug life, and to keep the engine from taking in water but never evaporating it.
that same cold running park avenue with more efficient cooling system?
Sit in traffic with that missing t stat and even cold out, watch it climb. The car has been able to take it, but only after having to runs the fans on constant high power (that’s a lot of amps btw and requires the pcm to see 225 without a rate of cooling it finds comfortable ) especially in gear because the transmission says hello to the coolant with its very efficient water to water transfer instead of water to air of the radiator and the water pump pulley is small so it spins a good amount at low speeds.
