I have a 2009 Dodge Ram 1500 with the 5.7. Alot of members are running 180 degree thermostats vs the stock 195 degree. There current oil temperature was 204 degrees with the stock 195 thermostat and as soon as they put in the 180 thermostat the oil temps went down 16 degrees. My question is what are the pros and cons on installing a lower degree thermostat? and is 204 degree oil to hot? thanks in advance
lower degree thermostat
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I have a 180 degree thermostat on my Dakota, but I have a 3.9 V6, not a 5.7. I installed the 180 tstat and I use copper core Autolite 3923 plugs to get rid of preignition pinging under a light throttle. What the 180 tstat does is trick the PCM into thinking the engine has not yet reached normal operating temperature, so the PCM gives a slightly more rich air fuel ratio and it advances the timing just a little.
My PCM has had the Chrysler 'death flash" done before I bought my truck. That was Dodge's answer to pinging complaints some years ago. It's a flash on the PCM that retards the timing by 4 degrees to help with ping and engine vibration at idle, and it doesn't work. It does however reduce power and once the death flash is done, it can not be erased.
The 180 tstat makes it impossible for the engine to ping and it helps improve power, but it can be detrimental to MPG. I have seen no real reduction in MPG in my truck with the 180 tstat. I don't know what it could do to the oil but I have been running it for 3 years now and have had no oil problems at all. Even Dodge engineers did a study and found that the Magnum engines made more power and ran more efficiently at 182 degrees but they had to use a 195 thermostat to meet Federal regulations for emissions and MPG. They also did a study and found that copper core plugs worked best in the 3.9 and other Magnum engines.
I would ask at a couple of Dodge dealers before using the lower temp thermostat on a 5.7. Or maybe email Dodge and see if they will offer any advice.
My PCM has had the Chrysler 'death flash" done before I bought my truck. That was Dodge's answer to pinging complaints some years ago. It's a flash on the PCM that retards the timing by 4 degrees to help with ping and engine vibration at idle, and it doesn't work. It does however reduce power and once the death flash is done, it can not be erased.
The 180 tstat makes it impossible for the engine to ping and it helps improve power, but it can be detrimental to MPG. I have seen no real reduction in MPG in my truck with the 180 tstat. I don't know what it could do to the oil but I have been running it for 3 years now and have had no oil problems at all. Even Dodge engineers did a study and found that the Magnum engines made more power and ran more efficiently at 182 degrees but they had to use a 195 thermostat to meet Federal regulations for emissions and MPG. They also did a study and found that copper core plugs worked best in the 3.9 and other Magnum engines.
I would ask at a couple of Dodge dealers before using the lower temp thermostat on a 5.7. Or maybe email Dodge and see if they will offer any advice.
Being a bit of a Dodge nut because of my dad's Chrysler past I would say that the 180F thermostat will be fine in this engine and shouldn't cause any problems emission related.
You may notice a decrease in your fuel economy though...
I know from talking to others on other forums that they have had some luck putting a resistor (i think it was) and a by-pass switch on the temperature control sensor. This way they can add it to the circuit in the summer and turn it off in the winter thus not affecting the amount of heat and running the engine too rich when it's not required.
Others have also gone to the scrap yard in search of a PCM that hasn't been flashed with the so called "Death Flash".
One member had great success adding an external oil cooler system with a fan that super cooled the oil. He would use a 5w20 oil and achieve extra cooling of the engine in this manor.
You have options!
You may notice a decrease in your fuel economy though...
I know from talking to others on other forums that they have had some luck putting a resistor (i think it was) and a by-pass switch on the temperature control sensor. This way they can add it to the circuit in the summer and turn it off in the winter thus not affecting the amount of heat and running the engine too rich when it's not required.
Others have also gone to the scrap yard in search of a PCM that hasn't been flashed with the so called "Death Flash".
One member had great success adding an external oil cooler system with a fan that super cooled the oil. He would use a 5w20 oil and achieve extra cooling of the engine in this manor.
You have options!
I am from the ls world and gm stuff but they must have some tuners able to fix this stuff.
I don't know but dodge/chry/jeep have a bunch of death things. Death wobble death flash ect.
I don't know but dodge/chry/jeep have a bunch of death things. Death wobble death flash ect.
What's the benefit of installing a cooler thermostat in an otherwise normally functioning engine?
Originally Posted By: tom slick
What's the benefit of installing a cooler thermostat in an otherwise normally functioning engine?
The only benefit really is a theoretical slight increase in maximum power from a cooler, denser intake charge, but might be offset some by increased cylinder wall friction and slightly colder thicker oil. The downsides hardly seem worth it.
What's the benefit of installing a cooler thermostat in an otherwise normally functioning engine?
The only benefit really is a theoretical slight increase in maximum power from a cooler, denser intake charge, but might be offset some by increased cylinder wall friction and slightly colder thicker oil. The downsides hardly seem worth it.
By dropping the temp of the oil from 204°F to 188°F, you are making the oil thicker. Using Mobil 1 5W-20, this temperature change would increase the oil viscosity from 9.2cSt to 11cSt, essentially making the 5W-20 oil a 5w30 oil. I'm not sure what the benefit is of doing this in an engine that's designed to use 5W-20 at full oil temp (212°F).
Originally Posted By: mechanicx
Originally Posted By: tom slick
What's the benefit of installing a cooler thermostat in an otherwise normally functioning engine?
The only benefit really is a theoretical slight increase in maximum power from a cooler, denser intake charge, but might be offset some by increased cylinder wall friction and slightly colder thicker oil. The downsides hardly seem worth it.
Does 15* in intake air temp really make any difference in power on a stock (or near stock) vehicle?
Originally Posted By: tom slick
What's the benefit of installing a cooler thermostat in an otherwise normally functioning engine?
The only benefit really is a theoretical slight increase in maximum power from a cooler, denser intake charge, but might be offset some by increased cylinder wall friction and slightly colder thicker oil. The downsides hardly seem worth it.
Does 15* in intake air temp really make any difference in power on a stock (or near stock) vehicle?
By dropping the temp of the oil from 204°F to 188°F, you are making the oil thicker. Using Mobil 1 5W-20, this temperature change would increase the oil viscosity from 9.2cSt to 11cSt, essentially making the 5W-20 oil a 5w30 oil.
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Huh? Wouldn't that mean my 5w-20 oil is 5w-50 before startup on a cold morning??
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Huh? Wouldn't that mean my 5w-20 oil is 5w-50 before startup on a cold morning??
A 15 deg drop in thermostat OPENING temperature does not equate to to a 15 deg drop in air intake temperature.
There CAN be some effect, but it is never 100%.
When you need cooling, the thermostat opens.
Open is open, no matter where the opening temp is!
You think Chrysler did not know about this?
BTW, I don't see how the oil temp would go down 16 deg when the rather unrelated thermostat opening temp went down only 15 deg.
With special tuning, a slightly cooler thermostat can be OK for the street. But this is for short term special tuning. Remember, when it is open, it is open. Stepping on the gas here and there for a quick burst is not something to tune your car for.
There CAN be some effect, but it is never 100%.
When you need cooling, the thermostat opens.
Open is open, no matter where the opening temp is!
You think Chrysler did not know about this?
BTW, I don't see how the oil temp would go down 16 deg when the rather unrelated thermostat opening temp went down only 15 deg.
With special tuning, a slightly cooler thermostat can be OK for the street. But this is for short term special tuning. Remember, when it is open, it is open. Stepping on the gas here and there for a quick burst is not something to tune your car for.
I'm running a 180* thermostat in my Buick's 3800 V6 to help prevent the intake gaskets from grenading (note: they were replaced 9 months ago with aluminum gaskets on the lower intake manifold, and a redesigned upper intake). The computer's also been tuned to flip on the fans at 186* F. This is to keep the engine and transmission cool in dense traffic. Fuel mileage is consistent since before the switch. I've been running it for 2 years now, and haven't noticed any negative effects.
The benefit from a cooler Thermostat is that in often stops the PING. If no ping is present, you can dial in 2° more timing advance.
Affect on oil is minimal.
Many computers think anything over 165° is hot as far as the engine goes and so it opens the loop.
There might be some small effect on fuel mileage.
Affect on oil is minimal.
Many computers think anything over 165° is hot as far as the engine goes and so it opens the loop.
There might be some small effect on fuel mileage.
ls1mike
$50 Site Donor 2026
I run a colder (both 180) thermostat in the truck for all the towing and a cooler one in the Buick to reduce detonation because of the extra boost.
We wouldn't get enough heat here in the winter in Canada as my 192 has trouble some really really cold days.
Originally Posted By: asamek
By dropping the temp of the oil from 204°F to 188°F, you are making the oil thicker. Using Mobil 1 5W-20, this temperature change would increase the oil viscosity from 9.2cSt to 11cSt, essentially making the 5W-20 oil a 5w30 oil.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Huh? Wouldn't that mean my 5w-20 oil is 5w-50 before startup on a cold morning??
No, the 5W-20 would be much thicker on a cold morning startup than a 50 weight oil would be at full operating temperature.
Using Mobil 1 oils again, Mobil 1 15W-50 oil has a viscosity of 18.1 cSt at full operating temperature (212°F). Mobil 1 5W-20 has a viscosity of 388.2 cSt at 32°F.
So a 5W-20 oil on a cold morning is over 20 times as thick as 15W-50 oil at full operating temperature.
By dropping the temp of the oil from 204°F to 188°F, you are making the oil thicker. Using Mobil 1 5W-20, this temperature change would increase the oil viscosity from 9.2cSt to 11cSt, essentially making the 5W-20 oil a 5w30 oil.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Huh? Wouldn't that mean my 5w-20 oil is 5w-50 before startup on a cold morning??
No, the 5W-20 would be much thicker on a cold morning startup than a 50 weight oil would be at full operating temperature.
Using Mobil 1 oils again, Mobil 1 15W-50 oil has a viscosity of 18.1 cSt at full operating temperature (212°F). Mobil 1 5W-20 has a viscosity of 388.2 cSt at 32°F.
So a 5W-20 oil on a cold morning is over 20 times as thick as 15W-50 oil at full operating temperature.
I'm not sure I understand the rationale for comparing a 5w-20 cold to a 15w-50 at operating temp.
I'm also unsure of the veracity of a 20 wt changing itself to a 30 wt due to temperature.
But whatever. I'm guessing the 20 wt is thinner than the 30, 40 or 50 wt at the same temp, cold or operating.
I'm also unsure of the veracity of a 20 wt changing itself to a 30 wt due to temperature.
But whatever. I'm guessing the 20 wt is thinner than the 30, 40 or 50 wt at the same temp, cold or operating.
The rationale is that, if you make a big change in the temperature of the oil in the engine at operating temperature, you also need to be aware that you are changing the viscosity of that same oil (seeing as how you have now set a new "normal" operating temperature for that oil).
If the original poster is correct in stating that the new operating temperature of is oil is 16°F cooler, he needs to be aware that this temperature reduction has effectively upped his oil by a grade. The 5W-20 that this engine calls for has now thickened because of this cooling and will now perform as a 5w30 oil.
If the original poster is correct in stating that the new operating temperature of is oil is 16°F cooler, he needs to be aware that this temperature reduction has effectively upped his oil by a grade. The 5W-20 that this engine calls for has now thickened because of this cooling and will now perform as a 5w30 oil.
Originally Posted By: asamek
I'm also unsure of the veracity of a 20 wt changing itself to a 30 wt due to temperature.
Here's a screenshot of Mobil 1 5W-20 and Mobil 1 5w30 compared with Widman's oil viscosity calculator.
Notice that if you decrease the operating temperature of the 5W-20 from 100°C(212°F) down to 90°C(194°F), the viscosity has increased from 8.8cSt to 10.9cSt, which is well into the 30 weight viscosity range.
The question for the original poster is if the increased frictional losses from the cooler, thicker oil will offset any horsepower gains from a possible cooler intake charge. My guess is that it will. He would be better off getting a cold air intake and keeping his oil operating temperature the same.
I'm also unsure of the veracity of a 20 wt changing itself to a 30 wt due to temperature.
Here's a screenshot of Mobil 1 5W-20 and Mobil 1 5w30 compared with Widman's oil viscosity calculator.
Notice that if you decrease the operating temperature of the 5W-20 from 100°C(212°F) down to 90°C(194°F), the viscosity has increased from 8.8cSt to 10.9cSt, which is well into the 30 weight viscosity range.
The question for the original poster is if the increased frictional losses from the cooler, thicker oil will offset any horsepower gains from a possible cooler intake charge. My guess is that it will. He would be better off getting a cold air intake and keeping his oil operating temperature the same.
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I made a mistake in my original post the oil was not 16 degrees cooler it was 25 degrees cooler, the motor ran 16 degrees cooler. This information came from a fellow member from a dodge forum, here is his post.....Got my jet 180 thermostate today.
before and after changing it out.
Before;
Engine temp 201 degrees.
Oil temp. 204 degrees.
Oil pressure 29.
Intake air temp.118 degrees.
After.
Engine temp.183-185 degrees.16 degrees cooler.
Oil temp.179 degrees. 25 degrees cooler.
Intake temp 102 degrees.16 degrees cooler.
Oil pressure 37. 20+ percent improvement.
Outside temp 82 degrees.
Noticeable power increase.
Transmission temp was 157 degrees with 180 stat,forgot to get before temp.
before and after changing it out.
Before;
Engine temp 201 degrees.
Oil temp. 204 degrees.
Oil pressure 29.
Intake air temp.118 degrees.
After.
Engine temp.183-185 degrees.16 degrees cooler.
Oil temp.179 degrees. 25 degrees cooler.
Intake temp 102 degrees.16 degrees cooler.
Oil pressure 37. 20+ percent improvement.
Outside temp 82 degrees.
Noticeable power increase.
Transmission temp was 157 degrees with 180 stat,forgot to get before temp.
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