Coolant Bypass Hose

Has anyone ever considered that possibly some of the SC's overheating issues could be due to the size of the coolant bypass between the thermostat housing and the waterpump inlet? I'm talking about the hose that links from the coolant temp sensor (for the gauge) to the inlet at the top of the waterpump housing. Isn't that at least 3/8 to 1/2 inch diameter recirculating a fairly large amount of hot coolant back into the motor instead of sending it to the radiator? It seems logical that this bypass should feed back into the main tube flowing into the radiator on top instead of recirculating hot coolant back into the motor making it more hot. I wonder if this design was intended as part of the government "CAFE" standard back then.

I just have this idea of possibly significantly reducing the flow in this area (making the passage much smaller) thereby increasing the amount of coolant that actually gets cooled by the radiator. if i had the tools to weld, i would try feeding it directly to the upper tube flowing into the radiator.

Anyone tried this yet, or any thoughts about this from a technical perspective?

read this-

quote:

"Coolant Bypass
The bypass hose allows coolant to recirculate within the engine, without passing through the radiator, as it does when the engine is warmed up and the thermostat opens. The bypass hose connects the thermostat housing and the water pump. The water enters the bypass tube through the bypass valve, when such a valve is fitted.

The bypass valve is sometimes operated thermostatically; it closes off the bypass hose when a certain temperature is reached. This increases the circulation of the coolant within the engine. Many cars don't need a bypass valve, because there is plenty of coolant going through the radiator hoses due to the thermostat."

i got this definition off a website, and it was basically saying that some cars have this bypass closed off when a certain temp is reached to increase circulation of coolant within the engine coming from the radiator. I posted this just to let everyone know i am not making this stuff up. i figure that i would just make the passage much smaller instead of using a bypass valve.

i think i'm going to try something like this on my SC to see if there is any benefit at all- and if not... so be it.

some more interesting facts-

quote:

"Most engines have a small coolant bypass passage that permits some coolant to circulate within the cylinder block and head when the engine is cold and the thermostat is closed. This provides equal warming of the cylinders and prevents hot spots. When the engine warms up, the bypass must close or become restricted. Otherwise, the coolant would continue to circulate within the engine and too little would return to the radiator for cooling.

The bypass passage may be an internal passage or an external bypass hose. The bypass hose connects the cylinder block or head to the water pump. There are two internal bypass systems that can be used on an engine.

One internal bypass system uses a small, spring-loaded valve located in the back of the water pump. The valve is forced open by coolant pressure from the pump when the thermostat is closed. As the thermostat opens, the coolant pressure drops within the engine and the bypass valve closes.

Another bypass system has a blocking-bypass thermostat (fig. 6-12). This thermostat operates as previously described, but it also has a secondary, or bypass, valve. When the thermostat valve is closed, the circulation to the radiator is shut off. However, when the bypass valve is open, coolant is allowed to circulate through the bypass. As the thermostat valve opens, coolant flows into the radiator and the bypass valve closes."

heck i dont run a thermostat and have fan on all the time on high for 4 yrs now no problems and never even on a 104 + day does it ever go over the n in normal takes longer to warm up but runs like a raped ape when its cold .

my sc likes to run at 180 deg max but has more power at 140 deg water temp
as long as oil temp is about 200 then no problems with engine wear.

mannysc said:

heck i dont run a thermostat and have fan on all the time on high for 4 yrs now no problems and never even on a 104 + day does it ever go over the n in normal takes longer to warm up but runs like a raped ape when its cold .

my sc likes to run at 180 deg max but has more power at 140 deg water temp
as long as oil temp is about 200 then no problems with engine wear.

Click to expand...

Hey Manny,

I was always afraid of doing it this way in the climate i live in. The ouside temp gets as low as 10 degrees in the winter, and i think i need to keep my engine temp in the 180 range to be able to use the heater. If i do it this way, it will not come out of open loop mode in the winter time. This does however sound good for the climate where you live.
btw, your SC will have more power running at 140 degrees because your engine temp sensor is making your eec run more timing and fuel at that temp.

I tried this... and

quote:

When the engine warms up, the bypass must close or become restricted. Otherwise, the coolant would continue to circulate within the engine and too little would return to the radiator for cooling.

it did not make much difference. what i did was to install a valve on the bypass hose to see if it would redirect most of the coolant back into the radiator stream/path. from what i saw on the temp needle it definitely got cooler, but not by much. don't know if was really worth it, but i guess every little bit helps. i did not completely close off the bypass because some of the coolant must flow thru there for the temp sensor to still function. ohh well... on to the next attempt to improve the SC.