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Discussion Starter · #1 ·
I know all about the rules of thermostats no colder than 180. BUT what if you’re running a cast iron gt40 lower? It’s on my 351 cobra and I stumbled on the lower about a year or two ago and I just got the car running but I’m seeing temps of 210-222 which is way too high for me. I know the cast iron intake is retaining more heat so would this be an exception to the rule of running a 160? I think I’ve already got a 180 in there. I’ll check though.
 

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Discussion Starter · #5 ·
That’s cool, never seen an iron one in person before. I’m sure Tmoss would love to port one of those lol.
Funny you mention it Tmoss hasn’t replied to my pm yet And it’s been weeks lol. I wouldn’t be having it done until winter any way and that’s assuming I can get this thing to run cooler with this intake
 

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Discussion Starter · #6 ·
A cast iron gt40 lower?

If you have a 180* thermostat and it runs 210, then it’s not the thermostats fault. Assuming it’s functional
I’m gonna order another 180 and a 160 just in case this is a cast iron issue. I’ve burped the coolant don’t hear any bubbles any more. I’ll do it again for good measure. Fans come on.

I should mention that I’m running distilled water with water wetter because from research I was told it would run cooler. I’m not opposed to going back to coolant though.
 

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If you have a 180 t-stat and its opening, then its the rad/fan not removing enough heat or water pump not circulating enough (not usually the case and not where I would look first). Likely not enough air going through rad.

What vehicle is this in?
 
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The perfect temperature for the cooling system is 212 degrees.

Typically your coolant temp should stay about 15 degrees hotter than the thermostat temp if your cooling system is functioning properly.

195 thermostat is the ideal thermostat.

A warmer thermostat will regulate temp better than a colder thermostat since you gain more dynamic cooling capacity.
 
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And, to be "that guy"...
It is NOT THE THERMOSTAT that ultimately determines where your cooling system runs, it is the exchange of heat at the radiator.
You could -of course- run a 220 degree thermostat and the temp of the water coming out of the housing to the radiator will have been regulated to 220. But then it hits your radiator and gets cooled.
You could also have a 160 degree thermostat, and even though it opens at 160, due to heat exchange or the lack thereof it runs hotter than 160.
Your "problem" is in the radiator/fan efficiency, NOT the thermostat or the cast iron lower intake.
 

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The perfect temperature for the cooling system is 212 degrees.



Typically your coolant temp should stay about 15 degrees hotter than the thermostat temp if your cooling system is functioning properly.

195 thermostat is the ideal thermostat.

A warmer thermostat will regulate temp better than a colder thermostat since you gain more dynamic cooling capacity.
For what engine?

Some of the factory cars I just worked on: 180*, 221* factory thermostats.

You can't just say this thermostat is "ideal" or "perfect". The answer is "it depends".
 

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Not sure about your 95, but I know foxbodies have some shrouds around the rad and below rad support to direct air into the rad. Do you have something like that in place?

Is the factory single fan working (you have verified it runs)? Any debris in the rad fins that could be blocking flow?
 
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Discussion Starter · #15 ·
Not sure about your 95, but I know foxbodies have some shrouds around the rad and below rad support to direct air into the rad. Do you have something like that in place?

Is the factory single fan working (you have verified it runs)? Any debris in the rad fins that could be blocking flow?
Yeah the fan runs and I don’t think sn95 have that
 

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I’m running stock radiator and fans on the 95 cobra
so the fan set points for a 95 cobra are
LOW ON: 216°
LOW OFF: 212°
HIGH ON: 226°
HIGH OFF: 220°

changing the thermostat doesn’t affect the on/off set points for the fan. It only changes the minimum operating temperature.
 
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so the fan set points for a 95 cobra are
LOW ON: 216°
LOW OFF: 212°
HIGH ON: 226°
HIGH OFF: 220°

changing the thermostat doesn’t affect the on/off set points for the fan. It only changes the minimum operating temperature.
Was just gonna say this... If op didn't change the fan on and off temps, the fans don't turn on to exchange the heat. When cruising down the highway, lower temps will be seen. Stop and go traffic you'll see 212 all the time.
 

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And, to be "that guy"...
It is NOT THE THERMOSTAT that ultimately determines where your cooling system runs, it is the exchange of heat at the radiator.
You could -of course- run a 220 degree thermostat and the temp of the water coming out of the housing to the radiator will have been regulated to 220. But then it hits your radiator and gets cooled.
You could also have a 160 degree thermostat, and even though it opens at 160, due to heat exchange or the lack thereof it runs hotter than 160.
Your "problem" is in the radiator/fan efficiency, NOT the thermostat or the cast iron lower intake.
I agree with what you are stating but it still dpends on the car. I have an 2006 Dodge SRT8. It came with a 203F thermostat and when I got the car one of the mods everyone said do was change to 180F and adjust the fan settings. I did this like 12 years ago and the car never gets above 200F now even setting in traffic. Depending on the weather my car operates between 185-195 with the 180F thermostat. With the 203F thermostat the car opeated between 208-218.
 

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Discussion Starter · #19 ·
so the fan set points for a 95 cobra are
LOW ON: 216°
LOW OFF: 212°
HIGH ON: 226°
HIGH OFF: 220°

changing the thermostat doesn’t affect the on/off set points for the fan. It only changes the minimum operating temperature.
Right on thanks for that. Only way to change that is in the tune correct?
 

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Yes, the tune.
But why would you want to change that?
It’s running where it’s designed to run.

lowering the set points just causes the fan to run longer, and depending on how low you set it, can just cause the fan to run constantly.
 
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