180 deg thermostat for 2003

[mwilson]

I've read a pile of threads on thermostats on several forums and nobody seems to get it... 2003 and newer engines have a fan that is controlled to fully engage at a certain temp PERIOD! I do understand that the cooling system is supposed to have a reserve of cold coolant "at the ready" when conditions are requiring its need. Either PWM or regular old viscous coupling, the fan is gonna do its thing regardless of what thermostat we use.

Running a colder thermostat is almost as bad as not using one at all! Think of it like having a fire extinguisher with 3/4 to 1/2 charge since the reserve is being heat soaked long before it is needed at a critical time. In layman's terms, the system will be flooded with hot water instead since the fan wasn't commanded to engage fully until after the entire cooling system nearly past its ability to reject anymore heat.

That's kind of why I'm wondering what made Louis change the thermostat in the first place, he may have a fan clutch that is getting soft.

Mike.

 

[BIGNASTY]

I have ran my 04.5 in the heat of the Calif deserts and all over the western US Winter/Summer and even a fun run in the winter to TN, ALL with a 180* thermo and it got the same mileage, had the same power and hardly even noticed the gauge needle being any different than when it had a 190* in it, And done pulling and not pulling weight

 

[AH64ID]

I have ran my 04.5 in the heat of the Calif deserts and all over the western US Winter/Summer and even a fun run in the winter to TN, ALL with a 180* thermo and it got the same mileage, had the same power and hardly even noticed the gauge needle being any different than when it had a 190* in it, And done pulling and not pulling weight

So why run a 180°?

The gauge on the dash is a close guess, it's driven by the ECM and not the coolant temp sensor. When compared to the reading via the OBDII it's close, but as sensitive or accurate.

 

[BIGNASTY]

So why run a 180°?

The gauge on the dash is a close guess, it's driven by the ECM and not the coolant temp sensor. When compared to the reading via the OBDII it's close, but as sensitive or accurate.

Because when I went to the Cum-a-part dealer that's all they had in stock at the time, and im NOT GOING TO THE STEALERSHIP !!! If it meant selling it I wouldn't go to a Stealership for anything.

 

[AH64ID]

Makes sense, I don't buy things from the dealer either if I can help it.. Thou they do have the best prices on the Mopar air filter, best available, and Mopar Winter Front.

 

[BIGNASTY]

I get my air cleaner from Napa its the gold, looks just like all the real thick ones. I think it was around 25 bucks. Maybe the addition of the Coolant filter I added makes a difference I DON'T KNOW but truly I have not noticed a difference in the thermo's

I wouldn't know about warm-up times I have an ESPAR heater so its always warm!!

 

[AH64ID]

The biggest difference will be towing heavy on a hot day, by the time the fan kicks in you are above the max allowed temp for a 180° thermostat, that is per Cummins.

 

[BIGNASTY]

What's the max in the summer pulling a 10k trailer up a 6% grade, Baker Grade it may have got to 210 215 I cant remember to be honest about it, drop off the top of the other side it ran a needle width under 200 but it was a warm day at 115* in the Calif Desert. When it comes time to change the cooling system parts for routine maint. I will get the 190 thermo just like the one that came out of the system OEM. I use Stant product MAYBE that's the difference.

 

[AH64ID]

212° is the max allowed from Cummins with a 180, so I would guess you are at the upper end of the limit since the fan isn't last of the equation.

 

[BillDriscoll]

WOW.... if the fan clutch kicks in at 215, mine has never been on since I owned the truck!! My gauge has never read above 202-205. and normal driving 75 on the freeway and around town is 195-200.
I did change thermostat years ago and put in part # 05086739aa from Cummings and I'm guessing that's a 190deg, but it must be top secret cause I cant find that info on the internet!! Why dont they just write it on the frigging box....

 

[AH64ID]

The thermostat itself should be stamped.

Depending on the software the temp may come on below 215, but that is where it goes 100%.

 

[LRutigliano]

Update: I'm over 1100 miles into my trip with approx 800 towing so far with the 180T. I love it, coolant temp has only come above barely 200F once while towing a big grade and once without towing on hwy 2 in montana. Fuel mileage has been good too. Trans temp is approx 155 to 160F towing and just above 140F not towing.

Regards
Lou

 

[BIGNASTY]

Told ya it made no difference in mine when I put a 180 in, I meen 10* really is it going to be THAT MUCH DIFFERENT?

 

[Prairie Dog]

I don't profess to more than the engineers at Cummins but I do know that one of the (many) reasons for the hotter stats is to keep crud from forming in the cooling system. THe higher temps also cause the fuel to burn more completely - I've seen this for myself on the emissions analyzer. It may take many tens or hundreds of thousands of miles to find you made a mistake in that regard.

OTOH, why does anyone think these modern engines are better off running cooler than what they were designed for?

 

[BIGNASTY]

I don't profess to more than the engineers at Cummins but I do know that one of the (many) reasons for the hotter stats is to keep crud from forming in the cooling system. It may take many tens or hundreds of thousands of miles to find you made a mistake in that regard.

OTOH, why does anyone think these modern engines are better off running cooler than what they were designed for?

Good ENOUGH!!! Question and I agree TOTALLY!!!

But then one would have to look at the person that makes this comment, and ask HIM the same question why would ANYONE!!! do this to a already proven Truck???



2003 Quad, 3500 SRW LB, 4WD, 6SPD, 305 H.O., 3:73 LSD. Smarty Jr., Westach Boost/pyro combo gage on pillar, SBC-ConOFE, FASS 95 Pump. PAC Brake. 1 piece DC driveshaft, GDP2u, 285/75-17 Toyo AT's, Centramatic Balancers, 6.7 HO HB, Finned AAM axle cover.

 

[cerberusiam]

In the summetime, doubtful one could even begin to quantify the 10 degree difference. In the winter and cold temps it would be better to have the hotter themrostat. Given how oversized and efficient the cooling systems are when every thing works it is just a matter of choice.