Will L.
Well-Known Member
Ok. Something blew fresh air on this ember smoldering in the back of my head this morning.
I was searching in vain for the rare 96 crossover without luck and looking at options when I came across these stand alone block off thermostat housings. One line in, one bypass out, one line to the radiator. See pic. Note date before noting prices.
So- i was simply hoping for one housing, 1 stat, and all proper sizes everywhere originally. Basically a mini crossover that needs a mount and is more compact than any of our factory crossovers. But this isn’t quite big enough. And there is always the arguments of dual stat housings flowing better. But two of these, the two bypasses T together to go back to the waterpump like normal.
Each one could get full flow from one head through a thermostat of its own for max flow and say the one head is hotter than the other by X amount. Fine, it opens some and starts shedding heat. I would need to have the two outlets join together with a T fitting (or a manifold that might get one way check valves) return to upper radiator hose.
Then the other two inlet fittings tie together with a T fitting and feed to the heater core. Same basic thing the original cross over did this joins the two thermostats where one head can warm the other’s thermostat by mixing water (again like the factory does). But this has a variable option: do not connect them here. They only join at the manifold. The manifold could feed the heater core. Remember one way check valves keep one head from warming the wrong thermostat.
On my system, originally the 4 bolt water pump, there was a second hose returning how water into the pump
To recirculate into the engine coming from the heater core. On newer hummers that got the spin on water pump, this other hose is as plumbed into the lower radiator hose. So when you are not using the heater- all this hot water is going back in and wrecking the cold water whose job it is to cool the engine. Ignorant but you need flow. I previously did systems where it returned to the upper hose- but the flow is obviously not great. Being in the desert- better cooling was more important that a comfort heater. I know the route of this heater output is different on trucks of different years- but it has been too many years for me to remember where they went. Please someone remind me. I can’t remember truck routing on the minor hoses.
Hummer surge feeds to and from lower radiator hose- so it’s is a good system flow and is an easy option for me. The heater output into the surge, the surge hose feeds to the lower radiator hose to create the draw. By going through the surge instead of directly to the lower hose, there would be less flow to the heater- but gives the hot water time to cool as it is mixed with cooler water more when heater is not in use.
In the older system of truck and hummer the heater hose going from crossover to output side of thermostat to radiator- was accomplished because the thermostat restriction (creating a pressure differential) so more flow is on the side of the housing to pusht the coolant through the heater core. Also the T fitting I made always had the 1” coming in ant and angle penetrating the line with the taper so it worked like a venturi- like an oil draft tube in race headers. But with the two independent or tied together block off thermostats- I don’t think there will be any pressure differential. That upper radiator hose is gonna flow like never before, so maybe the draft tube design could help more?
One of the engineers from Gm pointed out to me -The heater core system doesn’t help the regular cooling when off, it only hurts. They considered tapping the crossover before stat and using an electric pump that turned on when you turn on the heat, then would return direct to the upper radiator hose. Too much expense for moderate comfort gain because they couldn’t make good electric pumps handle the heat low cost enough back then. Now, it’s been in caddys for years. Amazing low failure rate. So I am strongly considering this. This also eliminates the flow valves that fail, and the two extra hoses in that system. Rigs like mine and suburbans with rear heat would perform much better.
When the heater is on, obviously it is a mini radiator- so in use it would only help the real radiator do its job better no matter the system.
Please - schematic of the heater hose routing from the different trucks? Manuals, hand drawing and pictures all good.
I know @n8in8or showed interest in this before and tried to find my old thread when I posted the pics before.
Oh yeah- almost forgot in my ramblings:
Many heavy equipment and generators that are V style engines from old 2stoke Detroits to new v16 caterpillars use two independent thermostats- and actually the down flow radiator is really two individual radiators that tie together at the lower hoses into one pump - through the block into each head and out individual thermostats.
It is such a reliable system it is the standard for large emergency generators for things like hospitals, police departments, city utilities, etc.
I was searching in vain for the rare 96 crossover without luck and looking at options when I came across these stand alone block off thermostat housings. One line in, one bypass out, one line to the radiator. See pic. Note date before noting prices.
So- i was simply hoping for one housing, 1 stat, and all proper sizes everywhere originally. Basically a mini crossover that needs a mount and is more compact than any of our factory crossovers. But this isn’t quite big enough. And there is always the arguments of dual stat housings flowing better. But two of these, the two bypasses T together to go back to the waterpump like normal.
Each one could get full flow from one head through a thermostat of its own for max flow and say the one head is hotter than the other by X amount. Fine, it opens some and starts shedding heat. I would need to have the two outlets join together with a T fitting (or a manifold that might get one way check valves) return to upper radiator hose.
Then the other two inlet fittings tie together with a T fitting and feed to the heater core. Same basic thing the original cross over did this joins the two thermostats where one head can warm the other’s thermostat by mixing water (again like the factory does). But this has a variable option: do not connect them here. They only join at the manifold. The manifold could feed the heater core. Remember one way check valves keep one head from warming the wrong thermostat.
On my system, originally the 4 bolt water pump, there was a second hose returning how water into the pump
To recirculate into the engine coming from the heater core. On newer hummers that got the spin on water pump, this other hose is as plumbed into the lower radiator hose. So when you are not using the heater- all this hot water is going back in and wrecking the cold water whose job it is to cool the engine. Ignorant but you need flow. I previously did systems where it returned to the upper hose- but the flow is obviously not great. Being in the desert- better cooling was more important that a comfort heater. I know the route of this heater output is different on trucks of different years- but it has been too many years for me to remember where they went. Please someone remind me. I can’t remember truck routing on the minor hoses.
Hummer surge feeds to and from lower radiator hose- so it’s is a good system flow and is an easy option for me. The heater output into the surge, the surge hose feeds to the lower radiator hose to create the draw. By going through the surge instead of directly to the lower hose, there would be less flow to the heater- but gives the hot water time to cool as it is mixed with cooler water more when heater is not in use.
In the older system of truck and hummer the heater hose going from crossover to output side of thermostat to radiator- was accomplished because the thermostat restriction (creating a pressure differential) so more flow is on the side of the housing to pusht the coolant through the heater core. Also the T fitting I made always had the 1” coming in ant and angle penetrating the line with the taper so it worked like a venturi- like an oil draft tube in race headers. But with the two independent or tied together block off thermostats- I don’t think there will be any pressure differential. That upper radiator hose is gonna flow like never before, so maybe the draft tube design could help more?
One of the engineers from Gm pointed out to me -The heater core system doesn’t help the regular cooling when off, it only hurts. They considered tapping the crossover before stat and using an electric pump that turned on when you turn on the heat, then would return direct to the upper radiator hose. Too much expense for moderate comfort gain because they couldn’t make good electric pumps handle the heat low cost enough back then. Now, it’s been in caddys for years. Amazing low failure rate. So I am strongly considering this. This also eliminates the flow valves that fail, and the two extra hoses in that system. Rigs like mine and suburbans with rear heat would perform much better.
When the heater is on, obviously it is a mini radiator- so in use it would only help the real radiator do its job better no matter the system.
Please - schematic of the heater hose routing from the different trucks? Manuals, hand drawing and pictures all good.
I know @n8in8or showed interest in this before and tried to find my old thread when I posted the pics before.
Oh yeah- almost forgot in my ramblings:
Many heavy equipment and generators that are V style engines from old 2stoke Detroits to new v16 caterpillars use two independent thermostats- and actually the down flow radiator is really two individual radiators that tie together at the lower hoses into one pump - through the block into each head and out individual thermostats.
It is such a reliable system it is the standard for large emergency generators for things like hospitals, police departments, city utilities, etc.