http://s1332.photobucket.com/user/fu...how/thermostat


The stock thermostat is on the left and the Murray 180 stat is on the right. They are very similar in size but they are not the same. The Murray unit is marginally larger and has to be modified to fit properly. I used a table mounted grinder to cut the overall diameter down a few hundredths. Not hard but take small amounts off at a time so you don't go too small. You use the factory rubber gasket off the original and the new stat should squeeze in almost flush against the flat mating surface of the housing. 2. 1/2 inch bolts hold it down. I used a large gallon zip-lock baggy as someone else suggested and it worked pretty well to recoup some of the fluid. I lost approximately 1 pint and recouped a quart. Also there is a handy wedge next to the throttle body (pic 3,5) that will hold the radiator hose up out of your way. Cover the alternator with a rag. (sorry for the crappy phone pics and photobucket sucks.)

The part is a MURRAY 180 degree thermostat Oriellly Auto part # 4128. This does not come up on there system for our D but only a 2005 Magnum with the 5.7 . $10 mod

Much cooler running. Check the thread some under hood temps I recorded. for temp differences before and after.

 

Great thread!

 

Great job. I have the jet 180 t stat and it fits without modification. Definitely runs cooler.

 

Has anyone noticed a longer time to reach operating temp with a 180' stat? I wonder if my fuel economy will drop if I install one with mostly city/short trip driving. Also has anyone had a code p0128 showup after installing the colder stat?

 

No and no. I've noticed no change in fuel economy.

 

No codes on this one bud. It's nice though to park for a half hour and when you come to restart your car the engine temp is 170-180 ish instead of 205. Just way way too hot stock IMO.

 

I have been studying engine temps and thermostats for almost 20 years. Early GTO's were prone to overheating. The primary reasons, if the cooling system was functioning properly, came down to the leanness of the fuel mixture and the ignition timing. After messing around with a 180 stat, no stat. no antifreeze just Water Wetter, flex fan without clutch, it turned out that 195 stat with an HD fan clutch, advancing the timing 3 degrees, and adjusting the idle mixture screws correctly would allow the engine to cool properly. On a cool day, if I watch, I can see the stat open at 195 (have an actual temp gauge). The temp drops to about 180 as the cooler water from the radiator enters, and then the temp begins to climb again. Of course, modern engines have little or nothing in common here. BUT they are designed like they are for a reason. Here is a link and the text from an article that advises not to try to lower engine temps with a stat that has a lower temp for opening. Of course, we are all entitled to our opinions, and discussing opposing viewpoints with respect usually leads to a consensus (at least it used to), or we politely agree to disagree.

http://www.tuneruniversity.com/blog/...the-advantage/
(they go back and forth between F and C)


Low Temp Thermostats: What’s the Advantage?

This week we’re talking about low temperature thermostats, another item that nearly every tuning house sells and yet fail to really explain what they’re for. A few months back, we talked about high pressure radiator caps and what advantage they offered, this time though we’re looking at a part that is far more perplexing.
Here are a few descriptions from websites/manufacturers selling these, notice the trend of extremely vague language:
The SPOON Low Temp Thermostat S2000 Integra Civic will increase the vehicles cooling ability (false) by changing the operation temperature from 90C (stock)[194] to as low as 80C [176F]. This in turn will give your Honda a chance to be free of overheating (false). For best results, it is recommended that the Thermostat be used in conjunction with a low temperature Thermo Switch.
The SARD Low Temperature Thermostat – SST12 Mazda is a drop-in direct replacement for your OEM unit. The Sard unit will lower the temperature at which the cool water can mix with the warmer temperatures inside the engine (true). This will lead to a motor than can now run much more efficiently (false).
The FEEL’S Low Temperature Thermostat Civic FD2 will provide better, more reliable and faster cooling for your FD2 (false). By lowering the opening temperature to 68 degrees, and full open at 82 degrees there is a smooth transition in cooling (???), and you engine will be cooled optimally faster (?).
The MUGEN Low Temp Thermostat NSX S2000 will increase the vehicle cooling ability (still false) by allowing the circulation of the chilled water earlier than the OEM unit would allow it to (that part, true). Stock thermostats are intended for normal driving conditions and aren’t made for those intending to give their car a work-out (false).
Reading these make you believe that a low temp thermostat are a good idea for those “pushing their car harder” and that they somehow improve cooling performance. There are other descriptions that also seem to indicate that they lower engine/intake temps to make more power. All rubbish.
The Function of the Thermostat & Cooling System Basics

The biggest misunderstanding about thermostats is that people believe they make the engine run cooler. They don’t necessarily do that. The cooling system and load on the engine determines how hot the engine gets, the thermostat fully open will still be the mercy of the coolant system’s ability to remove heat.
Most engines run slightly above the thermostat’s minimum opening temperature under normal loads. Under high loads, they will run at or above the thermostat’s fully open temperature – in other words, under hard driving, the thermostat’s opening temperature is completely irrelevant.
The thermostat can only determine when the cooling system is allowed to start cooling the engine. It sets a floor, not a ceiling on engine temperatures. The thermostat basically behaves like the hot and cold ***** in your shower, if the water is too hot, it turns the cold on a little more and if the water is to cold, it turns up the hot water. By regulating the flow through the cooling system it speeds up and slows down the flow of coolant into and out of the engine block.
In liquid cooling systems, the ability to cool is determined by a number of factors, but the basic keys are the surface area of the radiator (how big/how many small fins), the air flow through the radiator (fans on/off, speed of car), and how quickly or slowly the cooling fluid goes through the radiator. If the coolant spends a small amount of time in the radiator, it loses less heat. If it spends a lot of time there, it loses far more heat. Therefore you don’t want the flow to be too high as the cooling system’s ability to cool the engine will be reduced, not increased.
The thermostat is there primarily to help the engine warm up in the morning. As we discussed in a previous article, the engine is designed to operate at it’s operating temperature. Most engine wear occurs when the engine is cold, once it’s warmed up there is very little wear in a healthy engine. Thus, we definitely want to run a thermostat to allow the engine to warm up as quickly as possible until it reaches our desired and designed operating temperature.
If the engine is below operating temperature, the bearings, rings, and other components are not yet expanded in size and therefore they “bang” against the other metals in the engine more than they would at operating temperature. No good.
So if we don’t run a thermostat at all, it takes a lot of constant load to get the engine properly warmed up and to keep it up to temperature on cold days. We also in some circumstances may experience overheating if flow through the system is too high as the coolant has to spend a certain amount of time in the radiator to actually cool down.
Some race teams do choose not to run a thermostat, but they are the minority. They usually run at least a restriction plate in place of the thermostat to slow down flow and allow some warm up to occur. The reason that they may not run one at all is usually to remove a point of failure in endurance type races. In other words, if the thermostat fails and sticks closed, it could cause a pit stop or end the race. By removing it, they tolerate possible engine wear since they know they’ll be at high loads throughout the race. Their cooling system is usually tuned to compensate for the lack of a thermostat as well.
Running the factory thermostat will on the other hand ensure that the engine comes up to the designed minimum temperature very quickly. Until the engine is up to temperature, there is no cooling occurring. The factory thermostat will not however change how the engine runs under load because the thermostat will be fully open when under load. It effectively isn’t there under load.
What they’re used for

So what then would a low temperature thermostat accomplish? Not much.
Around town and in the pits, you warm up faster than no thermostat at all, but you will take a while to warm up from 160 to 180 for example. You will get there however, especially on warm days, the only difference is you’re trying to cool the car off as it’s trying to warm up. As a matter of fact, if you sit there at idle, the temp will go up until the radiator fans kick on since radiators are poor cooling devices without air flow. In other words, sitting still, the thermostat opening temperature doesn’t matter much at all.
Once you’re moving, on the highway, with a 160 degree thermostat on a cooler day you could be cruising at 160-180 degrees (opening temp->designed operating temp). This is possible because the load on the engine is low and the outside temps are low. Therefore, the thermostat opening temp matters somewhat here. If you’re coasting down a mountain, it will be a certainty that your coolant will reach the thermostat minimum if you coast long enough.
The problem with a low temp thermostat then for regular driving is that there are times when the car will be running at a temperature lower than it’s design intended. The result is increased wear on the engine’s internals. It’s essentially the same as if you assembled the engine with clearances tighter than designed for because you didn’t follow the directions or your tools were not calibrated properly.
As for the intake temperature argument, while cooling the intake manifold down could be useful, there are a few problems with the argument. The first is that very little heat is transferred from the intake manifold to the intake charge, period. The intake charge is moving very fast and there is a LOT of air flowing through. The surface area of the intake system is very small and the temperature differential in real terms is not that high. There is already very little heat being added to the intake charge by the intake system regardless of what some ads claim. If the new thermostat DID bring the temps of the intake manifold down 20 degrees, the actual change in intake temps would be negligible to 0 on the road.
Regardless, it would take literally a second or two before temps would be regulated by the cooling system, not the thermostat anyway since under load the engine is going to run well above the thermostat fully open mark anyway.
Remember that the thermostat is fully open pretty much any time the engine is under full load because the coolant temperatures spike pretty quickly.
In a race car, the floor (opening temp) of the thermostat is completely irrelevant unless you are running a very efficient and large radiator. Once you’re out on the track for half a lap or so, your coolant temps are going to be in the 200 range anyway so the thermostat is fully open regardless.
You can use a low temp as a “band-aid” at the track sometimes. For example, if you know that your coolant temps are hitting the opening temp of your current thermostat at points the track and you’re experiencing mild overheating, you might be able to patch this up by using a lower temp thermostat, especially if you’re willing to run your radiator fans manually to help.
Why? Because during low load parts of the track you allow the coolant system to cool off more which means it will cope with higher load sections a bit better and may chase of mild overheating problems. This is acceptable on a race track as a temporary solution as wear is usually an acceptable compromise to get through the race. However, the right solution is to upgrade the radiator or check for possible malfunctioning sections of the cooling system. It is also more acceptable here because load is high during a race. On the street, even on hard drives, it’s usually reasonably low.
Conclusion

So if you want to test this, the best thing to do is get an OBDII scanner and go out in an OBDII car and monitor the ECT sensor and watch how coolant temps regulate and spike as load changes.
The bottom line however is that in a street car, you’re increasing wear and getting no benefit. In a race car, it’s a band-aid but not one that you should plan to rely on.
If you’re having overheating problems, check the cooling system thoroughly and if all is well, upgrade the radiator, fans or even the water pump — not the thermostat. If your coolant gauge never goes above normal then your cooling system is adequate for your use of the car.
If you’re chasing more power, this isn’t a place to look. Any power gain would be circumstantial (ie, only under certain conditions), incredibly negligible, and at the risk of accelerated wear on your expensive engine internals (especially in street cars).

 

"The cooling system and load on the engine determines how hot the engine gets, the thermostat fully open will still be the mercy of the coolant system’s ability to remove heat" ...."Load" is the key word here

It sets a floor, not a ceiling on engine temperatures... this is true

The problem with a low temp thermostat then for regular driving is that there are times when the car will be running at a temperature lower than it’s intended..... this is false in the 180 degree range. Numerous tests have shown that 180 degrees and above range had minimal effects on engine performance with the only variations being a reduction in N0x and a slight increase in Hydrocarbons. All emissions tests performed by the PCM have already taken place and you have moved from Open loop to Closed Loop operation. At 180 the engine is fully warmed up the cat converters are lighting off and all is well.

If you’re chasing more power, this isn’t a place to look. Any power gain would be circumstantial (ie, only under certain conditions), incredibly negligible, Obviously the author has never operated a tuning program on a DYNO. If you were to look at how a PCM chooses fuel delivery, load and timing changes in their respective maps they would see that TEMPERATURE DIRECTLY AFFECTS THESE PERAMETERS. Some in a negative way and some in a positive way. For example if a durango is pulling a heavy load up a hill and the static engine temperature is 205 degrees the PCM would command a particular fuel, timing value based on LOAD, Temp, Volumetric Efficiency, Throttle Pct ,IAT, Transmission Gear. etc. Now assume the temp rises to 235 degrees as happens in this type of situation. Suddenly the knock sensor notifies the PCM of increased cyl pressure at this temp(235), the fuel map changes, commanding a richer mixture to cool the cylinder, both the IAT and Temp sensor read the higher temps prompting the Timing map to retard timing fighting to quench the detonation ( go boom ) and alas you have effectively lost horsepower when you need it the most (rich mixture and timing retard). YOU ARE NOT GAINING HP WITH THIS MOD! YOU ARE IMPROVING THE PROBABILITY THAT YOUR PCM WILL CHOOSE A MORE POWERFUL FUEL AND TIMING MAP.

and at the risk of accelerated wear on your expensive engine internals (especially in street cars)....

That is the funniest crap I have ever heard. Maybe running without a thermostat at all. These new engines /computers are all designed to get to operating temperatures (closed loop mode) as fast as possible for the good Ol EPA Smog. If you were to run your engine cold under 165 degrees you will run rich and possible wash oil off of the cylinder walls causing some wear over a long, long period of time but the PCM at that low temp would always be commanding a leaner mixture from the o2 sensors which would probably denote any wear. As long as you are in CLOSED LOOP MODE YOUR CAR WILL NOT Chew itself up.

Bottom line. You can safely run a 180 thermostat. You will be less likely to lose power due to detonation when in this temp range and as a bonus your radiator hoses will last longer....

 

Here is some REAL information regarding V8 tuning that is much more reliable than Internet opinion articles. Flip through these guys at your local barnes and noble.

Corvette Fuel Injection & Electronic Engine Control: 1982 through 2001. Updated for 2008
Charles O. Probst 8

Performance How-To: Engine Management; Advanced Tuning Manual
By: Greg Banish

 

Interesting info!