Coolant question

[Da67goatman]

What is the minimal volume of coolant required to cool a smallblock?  What if I run an aluminum radiator?  Its just for research purposes, Thanks.

[ohio hab]

I run water only in my sbc, with an 3 core aluminum radiator, and my truck runs 170 degrees. I only drive the truck in nice weather, and my shop is heated, during these Ohio winters. Antifreeze only raises the boiling point, and also keeps your block from freezing. The amount you have mixed has no bearing on how cool your sbc runs. The overall coolness depends on how your entire cooling system is installed. I have been running water only since 1988, in my 84 C-10.

[Da67goatman]

Sorry about wording, that changed the entire question, I rephrased the question.  Thanks for the response though.

[HAULIN IT]

Your revised post still leaves more questions than anything. Are you asking: "If I dump 1 gallon of coolant in my normal cooling system...Will it stay cool?" "If not, will 2 gallons of coolant work?" or are you asking "How small of a cooling system (radiator, hoses, ect.) can I make & still keep the engine cool?"
 The answer to either of the above questions would vary greatly based on many things. The outside temp, the H.P. of the engine, what your doing with the truck (driving on the highway, sitting in traffic or towing a boat uphills), type of fan, shroud, waterpump & even the product in the system...there are products (water wetter, Evan's waterless coolant, ect.) that are advertised to raise the boiling point. Also the "cool" has variables...Are you trying to keep the temp the same as a stock cooling system or just not overheating. Explain what you really are wanting to do & maybe we can help. Lorne   

[Da67goatman]

I revised my heater hoses and put valves in, to control water flow,  when I have the valve closed, there is just enough coolant to fill the radiator and block.  However with my stock radiator, it overheats, it almost went to the red on the gauge until I open the valve and let the flow into the heater cores front and rear.  So I want to know if the engine should be overheating with the heater cores bypassed?  I would like to know so I can tell if something is wrong with my coolant system.  Its like 20 degrees here so I thought it would be fine.

[Layne]

I run water only in my sbc

I thought that if you ran straight water, the water pump and whatnot will rust from the inside out?

[VileZambonie]

Yeah not good.

DA67 need more info on your setup

[Da67goatman]

Ok here's the setup:

Heater hose comes out of the pass head, runs through a valve into front and rear heater cores simultaneously, then runs back out through another valve an into the radiator.  With the switch in the "cab" I can remotely open and close the valves, stopping water flow in and out of the heater cores.  With the valves closed, the only water flow is through the large radiator hoses and thermostat.  I tried running the other day with the valves closed just to see (it was 12 degrees outside), and the gauge climbed to almost 260 before I opened the valves, then I watched the gauge drop back to the 210 mark (normal) in about 3 sec.  I am running the stock style radiator, its about 10 yrs old and has fresh extended life coolant in it (orange).

My question is: Should the truck overheat with those valves closed?

[beastie_3]

When you close off the heater cores, does the coolant get "blocked" by the valve, or does it get rerouted back to the engine? If thats the case, I would set it up so that when the cores are blocked, that line gets rerouted to the line headed back to the engine.

[Da67goatman]

It gets blocked, so all the coolant flow is through the large hoses.

[beastie_3]

I would set that hose so it completes its flow when the cores are blocked. Not like it will hurt anything.

[thirsty]

How is your t-stat?

[Da67goatman]

Its only like a year old and has 500 miles on it.  (195)

[HAULIN IT]

You have other problems. I haven't used a heater core in my truck in many years. I plugged the fitting on the waterpump & rerouted the intake hose...so there is less water running around not getting up to the rad/fan to get cooled back down. This is a "more finished" looking version of what you've described (when your valves are closed) I believe. My truck NEVER gets hot. Are you doing this to keep the hot water out of the cab in the summer? Why are you fooling with this when it's 20 degrees outside?
 One of my friend's dad had a '74 pickup all through the years we went to school. He was a handyman/builder guy, anyway, he figured out that the hot water was coming in the cab in the summertime. Sooooooooooo he made up 2 Red knob shutoff valves with soldered copper tubing & put them in the heater hoses. He shut them off in the summer & opened them in the winter...for all of the 16 years or so that he had the truck, he drove it everyday. They were quite a conversation piece the first time a few of us were there & he was changing his oil. Many of the '70's cars had a cable system to do a similar thing.
 As mentioned...I'd be thinking thermostat if your overheating in 20 degree weather. On a properly working system, you could probably only have the rad half full, block the grille & still not overheat in that kind of weather.
 ***Just re-read your last post***
 Oh, this is a Suburban? Lots more coolant & with dual "heat exchangers" (heatercores) away from the heatmaking item...in this weather they could be masking the problem some. Think about all of that hose & things.
 Stopping the flow isn't your problem, but I could see where it may "effect" some change. Try a new thermostat. Lorne

[Da67goatman]

I was playing with it just recently, cause it was warm enough inside to leave the heat off, but I finished the heater system in the fall.  I was thinking that it should cool just fine with the heater cores bypassed, but yeah there is like another 3 gallons for the rear heat, which could be masking the lack of cooling.  The radiator is always full, I regularly check all my fluids.  But I do know the radiator isn't the best, it has some sediment in it from a puddle misjudgment.  I do know that the gauge is inaccurate, I have a hand-held laser thermometer and when the gauge says 210 its really only 195, but it shouldn't have gotten up to 260 either way.  Thanks for the advice guys.