Any benefit from a cooler thermostat?

[JyRO]

I've heard of gassers getting some benefits from running a cooler thermostat and running a cooler temperature.

There must be some reason not to though or else why wouldn't Cummins/DC deliver the engine with a cooler thermostat.

Questions? Comments? Suggestions? Concerns? #ad


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Y2K 2500 Cummins ETC/DEE, SLT+, 4X4, Quad, LB, Intense Blue Sport, 3. 54 LSD, rear aux. springs (camper special), sliding rear window, all options except cab clearance lights including agate leather, totally stock engine, silencer ring removed, "stealth," mod to run fogs with high beam. Since everybody else listed their toys, I will too.
1995 Kawasaki ZX6-R (For Sale)
1990 Toyota Celica
1983 Mazda RX-7 GSL (For sale)

 

[MikeR]

I don't think it would work too well. The Cummins sure likes to run better when it's good and hot. I have noticed fuel consumption is greater when an engine is cold.

As a side note the engine is running hotter than what the temp gauge says. At full warm up,the temp gauge reads just a hair below the 190 degree mark (185-ish). When I plug in the ODB-II scan tool to read all the engine sensors,the temp sensor reports 195 degrees. That means the gauge is about 10 degrees inaccurate!

-Mike

 

[Alan Reagan]

Part of the reason for the hotter thermostat is emissions. Hotter the engine, lower the bad emissions. The engine is set up to run at that temp so I wouldn't lower the tstat value. My . 02 cents.

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2001 HO 6 spd 2500, 4. 10 LSD, Towing Package, Electric Brakes, SPA EGT/Boost Gauges, Running Boards, Fog Lights, Real Backup Lights, Running Boards

 

[Chad Sheets]

Hotter the better. Diesel truck/tractor pullers run the fan belt loose to get even more heat out of them (+250 deg). The "ideal" water temp for any diesel (rule of thumb) is 190-195.

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Always ready to help!
2000 2500 Red Sport quad cab, 4x4, K&N, DDI's, straight piped, boost, pyro and fuel pressure gages, Hot Power Edge, mean looking set of 33. 5" tires, Snap On diamond tool box, Marine Corps window sticker, Semper Fi!

1972 340 Cuda'. Original tripple Black, 340 car w/air. Good clean car, super stock springs, Weld Prostars, shaker hood, strong 340 with a 727/4000 stahl, 4. 56... . Bombs away!
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[Deezal Man]

JyRO,
Installing a lower temperature thermostat into a gas motor does two things.

Reduce fuel detonation in vehicles prone to this problem, especially one's running 87 octane.

In Fuel injected vehicles, a computer monitors and adjusts the amount of fuel to each cylinder, based on various parameters. One of which is engine temperature.

Like vehicles of yesterday, engines need extra fuel when they are cold. I'm sure quite a few of us remember using a manual choke in the morning...

During the warm-up process, the computer slowly decreases the amount of fuel to each cylinder... till full operating temps are reached. A cooler thermostat doesn't allow this state to be reached... therefore the computer thinks it needs to keep adding that little bit of extra fuel. More fuel means more power.

Naturally the downside is decreased fuel mileage & increased emissions... especially when you consider the meager level of increased performance.

A Diesel on the other hand does not favor cold temps. . as you probably know. I think it was Lyle Cummins who named the Diesel a "heat Engine" because it works on the principle of heat, in that it ignites fuel through detonation. .

The exact opposite of a gas motor.

Bottom line, a colder thermostat in a Diesel will decrease performance, due to insufficient temps needed to completely burn the fuel mixture.

AS for gas engine's... been there, done that too. . Was an "ok" idea when gas was less than a buck. But today, the benefit is too costly.

Naturally, OMO. #ad


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98. 5' 24v 2500 Auto/3. 54 4x4 SB QC 285-75-16's on Alcoa's. Everything but leather. PIAA 1200's, AMSOIL dual filter relocation system, Smittybuilt Stainless Steel Nerfs, Rhino Liner(Junk), K&N air filter(For Sale)15 year AMSOIL dealer. Time permitting, Soon to include Ultra-lite Pyro,0-50lbs boost, Trans temp in the pillar. Rancho 9000's with in cab adjustment.

 

[Okie-Go]

as for me I would'nt want to. It takes a heck of a load for the engine to get good and warm anyway. Sometimes in the cooler weather I almost think something is wrong, it takes a while to get the needle to move when the weather is cool. I am not a mechanic but if it is overheating something else may be wrong.

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2001 quadcab slt 2500 HO 6spd. LWB,2wd,dk garnett red, trailer tow package,camper special, anti spin 3. 54 axle, speed liner,oversized stainless steel chicken slide,66 gallon in bed aux. tank,K&N air filter,Reese 20k hitch, Terry 2000 EX 30ft. double slide 5er, 2000 20ft gooseneck for haulin jeep, firewood and huntin stuff. 5X12 tagalong for haulin the 4 wheeler. Okie Newton

 

[JyRO]

Guys - Thanks for your input. That was what I suspected. I am well aware of the characteristics of the diesel ignition cycle. That's why I didn't think lowering the temp would be beneficial.

Although, I'd never thought of it as you described it Deezal Man. You gave a good description, and I agree with your post. It makes sense what you said, but I'd always heard that (in a gasser) when you lower the temp. you'd getter better fuel mileage. I guess that's wrong in both gassers and diesels.

My truck doesn't overheat, BTW. I just thought I'd ask the question out of curiosity. #ad


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Y2K 2500 Cummins ETC/DEE, SLT+, 4X4, Quad, LB, Intense Blue Sport, 3. 54 LSD, rear aux. springs (camper special), sliding rear window, all options except cab clearance lights including agate leather, totally stock engine, silencer ring removed, "stealth," mod to run fogs with high beam. Since everybody else listed their toys, I will too.
1995 Kawasaki ZX6-R (For Sale)
1990 Toyota Celica
1983 Mazda RX-7 GSL (For sale)

 

[Deezal Man]

JyRO,
What you heard isn't wrong. I should have mentioned that reduced fuel mileage was a charactoristic of fuel injected systems. . The older carb motors did benefit from doing this trick. As the other guys said, Hotter is better. I've thought about installing a hotter thermo, to quicken cold starts and increase efficiency. But if Chad is right, it looks like the mighty Cummins is running where it should (190 degrees)

 

[Papa Joe]

Good thread. Thanks guys #ad