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Discussion Starter · #1 ·
Well im wondering if there is a way to modify a thermostat, or A company that sells custom temp ones.

As of now im not running a thermostat in the car. If it gets up to operating temp, it leaks. Just trying to get a thermo that will let it ride a couple notches above C, say 100-120.. Just enough to keep the heater warm on the highway.
 

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I think the question to be asked here is: "It leaks ... where?"

The most obvious culprit would be a bad radiator cap. Either perform a pressure test of the cap and the cooling system or even just start by looking for cracks around the sealing surface of the cap, and inspect the rubber gasket as well.



Having a pressurized cooling system is likely MORE important than attempting to lower the coolant temperature. A properly pressurized cooling system with the correct 50/50 mix of antifreeze and water will have a boiling point in the range of 250° F.

If it's leaking elsewhere, lowering the temp or the pressure in order to stave off the leak is a "band-aid" fix that isn't going to last, IMO.
 

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Discussion Starter · #3 ·
Its leaking out of the long radiator filler neck tube when it gets to operating temperature. The thing is, it never gets to operating temperature lol. I was just wondering if anyone makes a custom thermostat or if there is a way to modify one.
 

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Discussion Starter · #4 ·
The radi sits inbetween the frame and has to come out throgh the bottom and im not gonna mess with it right now. The heater is already hot enough when the needle is just one notch over the cold mark. If I get on the highway it's hard to get it there though.
 

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Ayuh,... While I completely agree with 66GMC,....

Marine T-stats come in 140°, 160°, or 180° models... Mercruiser atleast...
 

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Its leaking out of the long radiator filler neck tube when it gets to operating temperature. The thing is, it never gets to operating temperature lol. I was just wondering if anyone makes a custom thermostat or if there is a way to modify one.
So you feel it is the filler neck itself that is cracked or something? Is this a plastic tank or brass?

Sorry, but I really think you're barking up the wrong tree in your attempts to keep the engine temperature down that low. What year / make / model are you working on? Electric fan? Fan Clutch?

Sure, a marine application thermostat will open at a cooler temp than an automotive one ... but the lake is your coolant reservoir so there's plenty of cool water available! But in an automotive cooling system, you only have what ... 2 or 3 gallons? there's no way that your rad will keep the coolant that cool unless you're driving in the arctic (or even here in Alberta today, maybe.)

If it's a leak around the filler neck that only appears under pressure, and you're unwilling to R & R the rad to fix it properly ... try a cap with a lower pressure rating, or even run with the cap loose if you have to until you can get it fixed properly. You know that you're just buying time at this point, right? You'll need a fully functional cooling system by the time spring rolls around in hot-asz Texas.
 

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How can a thermostat "leak" it must be the thermostat housing or the hose connections to and from the radiator ?
I´d want to know what temp I have, not "a couple notches above C"


Summit has all of these.
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How can a thermostat "leak" it must be the thermostat housing or the hose connections to and from the radiator ?
I´d want to know what temp I have, not "a couple notches above C"
He said it's leaking at or around the radiator filler neck, not at the thermostat.
That's why I asked if it had plastic or brass tanks.

If brass, he may be able to be re-solder it.
If plastic ... perhaps something like Norton Speedgrip would re-seal a crack.
Either way ... these repairs *might* be possible without having to remove the rad.

The bottom line is that this rad is going to have to be repaired or replaced shortly, and all of this talk of COLD thermostats is futile, IMO.
As stated earlier ... I just can't see this thing NOT boiling over come springtime in Texas.
 

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Discussion Starter · #10 ·
Yeah the radi has plastic tanks. Ive been running it without a thermostat for two years now and it has gotten to the "mid way" inbetween cold and operating temperature MAYBE two or three times during normal driving. If im sitting in downtown fort worth in heavy traffic for half and hour or so it gets closer to operating temp and starts to leak. It spends all of its time 1 or 2 notches above "C". Except in the winter when I drive on the highway, then its hard to get it above "C".
 

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clean the area of the leak extensively and then smear a bunch of JB weld on it. believe it or not I did that to a radiator and it'll hold 20 pounds without a problem.

Running your engine that cold will destroy what's left of it.
 

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Well im wondering if there is a way to modify a thermostat, or A company that sells custom temp ones.

As of now im not running a thermostat in the car. If it gets up to operating temp, it leaks. Just trying to get a thermo that will let it ride a couple notches above C, say 100-120.. Just enough to keep the heater warm on the highway.
Start w/using a gutted thermostat (seen in my stash below). If needed use progressively smaller restrictors until you find the size that best suits the need. They're sold by Summit, etc. or make your own.



 
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