NAPA thermostat

[mroidt]

Hey guys

Changing coolant this weekend, and so, changing thermostat too.

Does anyone know why the Cummins thermo is $75 and is there anything wrong with the $35 NAPA?



Or why I should use the Cummins?



Will this NAPA thermostat cause that big fluctuation in temp as on the

early 2nd gens?



Thanks for replies

 

[Hendricks]

gota napa one in mine no problems yet.

 

[mroidt]

How about a Mopar thermostat found that today for $20?

Anybody had problem with them?

 

[Valv]

I am following up this since I need replacement too.



Is it better getting a 180deg for summer months or stick with 190 deg ?

 

[ASimpson]

I Need To Do This Also. What Anti Freeze Does People Recommend Im Actually Gonna Try To Do It This Weekend So Lets Hear Those Coolant Reccomendations And The Amount It Takes.

 

[Hitec.Redneck]

Check out this thread. I used this method on my 2002 that is posted in reply #5 by Steve St. Laurent, this process worked great.



https://www.turbodieselregister.com/forums/showthread.php?t=109291&highlight=thermostat

 

[keimmmo]

There are a few things to consider in deciding if you should run a hot or cold thermostat.



If you tow heavy, I would recommend the cooler thermostat to keep coolant temps down for the long hard pulls!



If you have an automatic trans, the fluid is cooled/heated by the water in the cooling system. To keep the trans fluid cooler, the cooler thermostat helps.



On the other hand, the heater doesn't work as well with the cooler thermostat. If you live in a cold area, you have to decide if you are willing to change the thermostat twice a year or live with either the hot or cold one.



Steve Keim

 

[rono]

Just bought a 180 yesterday from the local Freightliner dealer for $29. 95. + tax. The Cummins number is 3967195. Will be changing my coolant and t-stat shortly.

Ron

 

[VOGLER2001]

hey guys

changing coolant this weekend, and so, changing thermostat too.

Does anyone know why the cummins thermo is $75 And is there anything wrong with the $35 napa?



Or why i should use the cummins?



Will this napa thermostat cause that big fluctuation in temp as on the

early 2nd gens?



Thanks for replies

what was the napa part number?

 

[AH64ID]

If you tow heavy stick with the OEM thermostat temp. The fan clutch operates around the OEM thermostat and won't engage when needed for a cooler thermostat and will engage too much with a warmer thermostat.

 

[BIGNASTY]

I am following up this since I need replacement too.



Is it better getting a 180deg for summer months or stick with 190 deg ?

Ive been running a 180 for a long long time and have experienced absouletly no discernible difference in Desert Temp to 120* to cold mountain
temps -30* temps

 

[Tractorat]

Ive been running 180 for about a year (down to about 14d or colder and no difference in heat. Heater works great. Also, the 180 is better for the engine, is it not ? It was recommended and installed by the top diesel shop in the pnw.

BTW, these trucks are not inexpensive. Even when old. I can never figure out why someone would cheap out on a t stat rather than getting an actual cummins. Or any non oem part when they are available. Just me I guess.

 

[Mark31]

If one was pulling a load up the Davis Dam road on a hot day, how much cooler would would the coolant be at the top with a 180 thermostat than with a 195? Wouldn't both thermostats be wide open? If a truck is running hot with a 195 thermostat, I think it would run hot with a 180, just take a few minutes longer to get there, at best. If air can't flow through the radiator, if the water can't circulate, and if the fan clutch won't work, an engine is going to run hot. Look at Helicopter's post 10. HE KNOWS SOME STUFF. It is too easy to "put a band-aid on cancer" by just putting a cooler thermostat in. Then when winter comes, change thermostats? Put a Cummins and parts house stats side by side and look at the difference. I use distilled water and Gerex G5 because it meets the specs and I ain't smart enough to argue about what else might/will work. If Cummins is smart enough to make an engine, I think they are are smart enough to talk about its care and feeding, except maybe Cummins /Bosch for not having good enough fuel filtration when they started the common rail. But they learned. Think about it. Mark

 

[AH64ID]

If one was pulling a load up the Davis Dam road on a hot day, how much cooler would would the coolant be at the top with a 180 thermostat than with a 195? Wouldn't both thermostats be wide open? If a truck is running hot with a 195 thermostat, I think it would run hot with a 180, just take a few minutes longer to get there, at best. If air can't flow through the radiator, if the water can't circulate, and if the fan clutch won't work, an engine is going to run hot. Look at Helicopter's post 10. HE KNOWS SOME STUFF. It is too easy to "put a band-aid on cancer" by just putting a cooler thermostat in. Then when winter comes, change thermostats? Put a Cummins and parts house stats side by side and look at the difference. I use distilled water and Gerex G5 because it meets the specs and I ain't smart enough to argue about what else might/will work. If Cummins is smart enough to make an engine, I think they are are smart enough to talk about its care and feeding, except maybe Cummins /Bosch for not having good enough fuel filtration when they started the common rail. But they learned. Think about it. Mark

I bet the 180° would be just as hot as the 190° based on the temperature settings of the fan. The issue with dropping to a 180° thermostat with a 190° fan is the 180° thermostat hits heat rejection capacity at 212° and the 190° isn't fully open until 207° so you end up above what Cummins calls the "max allowable temp" of 212° on the 180° thermostat with the 190° fan. Basically operating at 215° is ok with a 190° thermostat and bad with a 180° one.

180° cracks at 180°, fully open at 198°, and max allowable of 212°
190° cracks at 190°, fully open at 207°, and max allowable of 225°

 

[Mark31]

One more thing and I will "cease and desist". I have no desire to "cross swords" with anybody on TDR. A lot of you have forgotten more than I will ever know. Let me ask this for your consideration. When running a cooler thermostat in the winter, how does that effect engine oil temperature? From my little bit of reading, I gather that oil engineers want their oils to run within a certain range. In cold weather, I would want my engine oil to get into that ideal range without the possible delay of a too cool thermostat. Is my thinking messed up?

 

[AH64ID]

160° is the minimum temperature for full power opearions from Cummins.

I generally don’t reccomnend full power below the operating temp of the thermostat thou. This will help recuce excess coolant pressure.

 

[CTaylor]

Correct me if I'm wrong but aren't the Cummins thermostats specifically designed to fail in the open position unlike other that may stay closed?