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Hey guys I've searched here for a few days a d cant seem to find anything on which brand of t stat to go with. I've decided to go with 180 stat and change my fans to come on at 200. Problem is what fricking high flow t stat should I get. I've read that stewart are made in china now and lots of people have had problems with Stant. Soooooo what high flowt stat is known for quality that will not fail ???
You need time for the coolant to absorb the heat. High flow thermostats are more marketing than science.
I've tried every T-stat combination on these cars and many others. A lower T-stat only works when you have a cooling system operating properly. I can't tell you how many times people want to to go to a lower T -Stat and have a clogged Radiator and 10 year old coolant and wonder why their car runs a little hot....which in reality is intended by GM by design.
Change the intake manifold gaskets to a 1204. The factory water passages on the rear are partially blocked by design. That will add some "high flow" right there...
I guess I just don't understand what is trying to be accomplished by using a lower temp thermostat.
A 160 is going to open sooner than a 180 but once they are open both will be fully open and since these engine operates above both those temps they will stay fully open and circulation will be the same. The system will achieve a stable temperature.
If you really want to run cooler you have to increase heat extraction at the radiator. That means more surface area and more air flow. But what is the goal? To have the engine operating lower than design temp?
Increasing "flow" decrease heat extraction. If the water runs through the block too fast it doesn't have time to transfer heat to the coolant. Same on the radiator side, coolant moving through too fast doesn't allow heat to be transferred to the air.
If your going to run below design temps, then you need to remap the ECM since engine temp is part of the equation for fuel/air ratio.
If your goal is to stop overheating, maintain the system properly.
Just posted this in another thread. I have a 190 failsafe. I tested it in a pan of water against a new 190 AC Delco. The failsafe started to open a few degrees sooner. BUT BUT it opened wider much faster. At 195 it was three times more open than the AC Delco. I have a Dewitts single row and cruise on a hot day at 188. Never get over 200. All thermostats do not open at the same speed. Dan
Let me see if others have experienced what I have with AC Delco thermostats. If all else is fine your car will cruise at about 194. If you drive hard on a hot day and turn the engine off for say 10 minutes. When you start back up the engine has heat soaked to 206 and when moving the temp goes quickly down to 187 and then creeps up to 197 and only then comes back down to 194. At 206 it is open enough to quickly cool down but at 187 it is almost closed. This failsafe does not do this as it is half open at 193 which allows the car to run at 187. Dan
Let me see if others have experienced what I have with AC Delco thermostats. If all else is fine your car will cruise at about 194. If you drive hard on a hot day and turn the engine off for say 10 minutes. When you start back up the engine has heat soaked to 206 and when moving the temp goes quickly down to 187 and then creeps up to 197 and only then comes back down to 194. At 206 it is open enough to quickly cool down but at 187 it is almost closed. This failsafe does not do this as it is half open at 193 which allows the car to run at 187. Dan
ok so high flow t stat is basically useless what about putting In a high flow wp what are your thoughts on those and what brand do you recommend ? I do not want to have to tear my engine apart again once I do the headgasket I'm just doing things bc it will be open ? What else should I change while doing the head gasket???
All the stock/replacement parts should be better than good enough. What problem are you looking to solve?
Having said that, more water flow improves cooling. So a higher flow pump/stat/whatever could help if you have a problem that needs help. But the factory cooling system is better than good enough, when properly maintained.
I guess I just don't understand what is trying to be accomplished by using a lower temp thermostat.
A 160 is going to open sooner than a 180 but once they are open both will be fully open and since these engine operates above both those temps they will stay fully open and circulation will be the same. The system will achieve a stable temperature.
If you really want to run cooler you have to increase heat extraction at the radiator. That means more surface area and more air flow. But what is the goal? To have the engine operating lower than design temp?
Increasing "flow" decrease heat extraction. If the water runs through the block too fast it doesn't have time to transfer heat to the coolant. Same on the radiator side, coolant moving through too fast doesn't allow heat to be transferred to the air.
If your going to run below design temps, then you need to remap the ECM since engine temp is part of the equation for fuel/air ratio.
If your goal is to stop overheating, maintain the system properly.
Heat transfer is always improved by increasing flow... you'll have a lower temperature gradient (water temp not as hot or drastically different) but it will be better. If that weren't the case, a fan on low would make you feel cooler than a fan on high. Same principle.
Also I run a stant 180 in my car. Works fine, car runs at 178 on anything below 90 while moving. Still creeps up while stopped but what won't.
Increasing "flow" decrease heat extraction. If the water runs through the block too fast it doesn't have time to transfer heat to the coolant. Same on the radiator side, coolant moving through too fast doesn't allow heat to be transferred to the air.
This is WRONG. Dead wrong.
Originally Posted by belairbrian
If your going to run below design temps, then you need to remap the ECM since engine temp is part of the equation for fuel/air ratio.
. This is...also WRONG. Any of us have to "remap the ECM" when we start our cars when they're cold? None of has. How can that be!? It can be, because the "map" for running at any temp...ALL temps from -40*F to 250*F or higher...that "map" is already programmed into the ECM! This is why the engine has a Coolant Temp Sensor....so that it can reference the right fueling for virtually any conceivable operating temp! THINK.
Originally Posted by belairbrian
If your goal is to stop overheating, maintain the system properly.
This part, at least, was right.
Those who are concerned with "designed temps", I ask you; Which temp is the "right one"? The LT1 comes stock, with a 180* stat...and like "84 4+3", my car can get down into the 170's. But the fan doesn't come on until 228*. So if I'm on the highway, I could be as low as 175*. Sitting in traffic, it could hit 230*. That is a whopping 55* range...that was "designed in". So which number is the "right designed one"?? 175? 230? A number in between? Which number in between is "right"?? I'll tell you: NONE. ALL. NEITHER. ANY. For more on this, I highly suggest giving THIS THREAD, a read.
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Last edited by Tom400CFI; Feb 2, 2020 at 12:48 AM.
Your ACDelco t-stat may have been made by Stant or Motorad to ACDelco specs.
Or may have been made by Stant or Motorad and put in an AC Delco Box like the International CPS with International instructions in plastic bag is put in a pretty blue box and costs more money.
You are correct. People who don't see any change have something wrong in their cooling system. If one has a radiator caked with "goo" It won't do anything. But on a perfect system it will. I have performed this test on 3 cars. 96 Viper, 2011 Ram 1500, 2009 Challenger SRT8. All had significant temps lowered at idle.
Going from memory the Challenger would hit 215* very quickly at idle on a hot summer day. With a 170 T-stat it would take much longer and never hit the 215. about 210. the key here is to have the fans reprogrammed to come on sooner. With that it never goes above 195*.
Truck was about the same.
The viper had the biggest change but I drilled 2 holes in the T-stat. It would hit 220 by design at idle. After the T-stat change it wouldn't get past 200* I could have had the fan reprogrammed to come on sooner but 200* is a sweet spot for that car. I ran these test in the summer. About 95* ambient temp.
Yep. And if you think about examples, it can be revealing as to how heat transfer works. Here is one good example:
Originally Posted by 84 4+3
Heat transfer is always improved by increasing flow... you'll have a lower temperature gradient (water temp not as hot or drastically different) but it will be better. If that weren't the case, a fan on low would make you feel cooler than a fan on high. Same principle.
Last edited by Tom400CFI; Feb 2, 2020 at 09:59 AM.
Since the original question was about a high flow thermostat. I see two way to get "high flow". One is to install a 160 that is wide open at 190 but can overcool at times OR get a failsafe that opens real fast at the temperature you want. By my experiments an AC Delco is only "high flow" at over 205 degrees. Maybe other brands also open fast also I have only tested the failsafe and an AC Delco.