Engine/Transmission (1998.5 - 2002) Cummins Thermostats 180*/190*

[BHolland]

My thermostat on my 99 is aparently stuck open as the gauge needle barely moves off the 140* mark. I went to my local Cummins parts counter and asked for a 190* thermostat. After getting my motor number the parts guy said the 190* is not recommended for a 99 CTD. I took a 180* but was wondering if I got good poop from the parts guy? I am running a stock truck and my local temps are typically in the 30's and lower this time of year.



Bob-Oregon

 

[DavidC]

Parts guy is right. If you need it to heat faster you need the cold front covers. I personally do not have that problem



Dave

 

[LanceH]

I put a 180 in my truck and like the way it works. I also noticed an engine temp difference while towing. Engine used to overheat on long hard pulls and now doesn't get near as hot. We normally are around 0 degrees during the day and about 14 to 20 below at night and haven't had a heater issue yet. truck warms up a bit slower than most but not sure if it has anything to do with the thermostat.

 

[RustyJC]

A 190 degF thermostat, if operating correctly, will not cause overheating when towing. Mine runs a needle width below the 190 mark when empty and a needle width above the 190 mark when towing. It doesn't overheat even in the Texas Hill Country during 100+ degF days.



Rusty

 

[Bob4x4]

The early 24v use 180 then went to 190 in later years. My 05 has a 180



Bob

 

[BHolland]

I think I will go ahead and install the 180* and buy some of Eric's cold fronts. I purchased a set from JC Whitney but they were Lund and a joke.



Bob - Oregon

 

[Nate]

A person could always use the 180* in the summer and the 190* in the winter. It's not even a 10 min job to change out.



I was thinking about it, but the 190* T Stat is $70.

 

[rweis]

I have an 02 that came with a 190*. Changed it to the 180*. Tow heavy. The change in tstat does not change the overall cooling ability, just starts the cooling sooner. I have zero problems towing with the 180* but I am in flat Florida and Smokies occassionally.



Bob Weis

 

[jkalchik]

A person could always use the 180* in the summer and the 190* in the winter. It's not even a 10 min job to change out.



I was thinking about it, but the 190* T Stat is $70.

The tstat in my 99 stuck open last fall. The local Cummins service counter had the stock replacement for $36.

 

[OL RATLR]

The tstat in my 99 stuck open last fall. The local Cummins service counter had the stock replacement for $36.

Must be nice they are $67 here.

 

[Ragain]

You havent been losing any coolant, have you? My temp needle stayed bottomed out until I put a new head gasket on. I replaced the thermostat at the same time, but after testing my old one, I found it was functioning correctly. I have all kinds of heat now! If you run a winterfront, be careful that you don't forget its on there. I also run an old 359 Pete (mechanical Cummins Big Cam 400) and I hesitate using the winterfront because it is so darned easy to forget it's on when the day warms and I am pulling a hill.

 

[Nate]

Yup, the 180* is that price. The 190* is about $70.

The tstat in my 99 stuck open last fall. The local Cummins service counter had the stock replacement for $36.