Engine/Transmission (1998.5 - 2002) No Thermostat is even better than 180

[Morepower]

I removed the guts out of the extra 190 thermo and reinstalled it. I couldn't be happer with the results.

 

[HEMI®Dart]

I can't build any heat into my cooling system.



A potential problem could be a "low coolant temp" fault code this fall when it cools down outside.

 

[dmurdock]

If your going to run without a thermostat, I'd run a restrictive orifice to build some back-pressure against the water pump or you could run into a cavitation problem.

 

[Texas Diesel]

This is a REAL bad idea with a $30k truck.

 

[Morepower]

I do have the old 190 thermostat body in place. So the opening does have a little back pressure. I don't have a problem with building heat into the cooling system with the way I drive and options. I do plan to reinstall the 180 when things cool down.

 

[Pit Bull]

If your truck came with a 190, then that is what it is setup to run with. Why would you want to change it to a 180? It's not going to make it last longer or give you better miles per gallon. But it could have a negative impact on your engine, unless you modify the ECM. Just a thought.

 

[Morepower]

The main reason is because I want the cooler oil temp. Since the oil and water track in temp closely. This way I go above 1250 EGT for short burst with out melting a piston. Another reason is towing on the down hill side I can cool down more before going up another incline. It will allow me to stay in a higher gear and stay near 1250 longer.

 

[MikeR]

what??!!

A friend of mine had an old saying for this... . "a false sense of security".

It's not going to make one bit of difference in your oil temp, sorry. 1250 is nothing. Heck, you can run to 1600 deg for short bursts without melting pistons. Many of us have already been there.

 

[KatDiesel]

Originally posted by Pit Bull

Why would you want to change it to a 180? It's not going to make it last longer or give you better miles per gallon. But it could have a negative impact on your engine, unless you modify the ECM.

Actually I believe someone has posted a milage gain when going to the 180° thermostat.

 

[Morepower]

I am with you on this one. I run my truck flat out with EGT through the roof for short runs like 1/4 runs, freeways on ramps and stop light racing. I was just trying to be politically correct in recognizing the 1250 safety limit for extended towing.

 

[Vaughn MacKenzie]

Slow warmup, not good

Even if you live in a warm climate, an open T-stat will increase your warmup time. Engine wear occurs at a much higher rate when cold up to about 120F. Also combustion is not as complete below 140F.



Pit Bull, many members have changed their 190F T-stats out for 180s and seen improved results. I think Cummins installed 190s in the trucks delivered to northern tier states and the others came with 180s. I live in Washington and got a 190 but changed out to a 180 and added a little margin of safety. The climate in this part of the state is equivalent to central California in the summer.



Vaughn

 

[David Oxland]

I think this is faulty thinking.

When you remove a thermostat you take away any control at all.

The water can go any way it likes giving poor warm up and likely overheating under heavy load.



The thermostat is what forces the water to go through the rad or bypass it.

David

 

[FASTERTHANU]

NO T-STAT

FAULTY THINKING IS CORRECT... THE 180 STAT INCREASES THE POWER OUTPUT BY FOOLING THE ECM. WITHOUT A THERMOSTAT YOU ARE NOT ALLOWING THE HOT COOLANT TO STAY IN THE RADIATOR WHERE IT IS COOLED BY AIRFLOW... IT WOULD SIMPLY RECIRCULATE AT EVER INCREASING TEMPERATURES WERE IT NOT FOR THE TOTAL OVERKILL OF THE COOLING SYSTEM. I'M SURE YOU WILL FIND THAT UNDER HEAVY LOAD, WITH HIGH OUTSIDE AIR TEMP, THAT YOU ARE A MELTDOWN WAITING TO HAPPEN

 

[brobeson]

180 or 190

When I talked to cummins about my over heating problem on my 2001, Cummins said they like the 180 thermisat, Dodge needed to go to the 190 for low emissions, cummins said there was no computer differances between the 180 and 190.



I installed a 180 in mine as per cummins.

 

[Okie-Go]

Everybody has an opinion. I went with what came in it. Did the coolant change today and replaced with a 190 from cummins. I have never ran hot and pull some good size loads. I live in South East Texas, fairly warm in the summer. The coolant still had good color with no buildup or residue that coulds be seen. 49,682 miles. My 2cents.

 

[THancock]

Morepower already stated he only took the guts out of his 190 and then put it back in. Thus, he does have restriction in the system that allows the water flow to be slowed down and get cooled in the radiator. We use restrictors all the time in radiator systems and they work fine.

Secondly, the system without a tstat doesn't let the water go anywhere it wants, like a post above suggested. If there is no tstat in then the water all circulates thru the engine and radiator. If there is a tstat in the system then when closed, the water just goes round and round in the engine and when warm enough it opens and the water then goes into the radiator.

What he is doing isn't a real good idea, but in the heat of summer and with his restriction(old 190 gutted) he more than likely isn't going to harm anything. He will find he has a problem when the weather turns cool again, but he has also stated that he's putting a working tstat back in before that time.

Hope this clears up some misconceptions.

 

[Mundgyver]

Morepower



If you are concerned about oil temp, why not put on a secondary oil cooler. My oil temp runs 10 degrees higher than my water temp. I find I have to really be pulling hard to get it up to 210 and that is only if the water temp goes above 190, otherwise it always runs around 200 to 205. I too, am looking to lower my oil temp, but I have not found a satisfactory esternal oil cooler yet.

 

[THancock]

If you're only running 210* of oil temp when pulling hard, why would you want an aftermarket oil cooler? That temp is nothing to concern yourself about. In fact I don't think I'd want mine much cooler than 200* anyway.

 

[JJW_ND]

Some 12V stats for comparison

You 24V guys should be happy you can keep such warm coolant temps. I would need to keep my winter front on to get coolant temps to 190 in the summer time.



IMHO... coolant temps between 180 - 200 are ideal for MPG. When it is very hot out or when I have my winter front on and temps are getting pretty warm (fall and spring) I get my best MPG. Oil is hot, coolant is hot!



Washdown????? My summer coolant temps run 165 - 175. Oil temps run 295 - 205. Exactly 30 degrees difference like Cummins said they would (12V). Cummins also said to keep oil temps under 220 if possible. I have got close to 220 (illegal loads on very hot days) but never over. I pull oil samples every 6K and have never had fuel in the oil. Even in the winter when oil temps never get about 180 and coolant has a hard time getting over 150. NEVER!



My work truck is a 2001 HO 6sp. I scared my how "hot" it ran. Even on 70 degee days it ran 200 to 210 on some hard pulls or pulling into on a windy day. When it final pulled in temps in the 80s and all over MT, WY big hills grossing 20,000 and never could get it over 210 I realized all is well and not to worry about it.



I really doudt over the long haul a 190 stat will give better MPG then a 180 stat. I would run a 180 if always pulling to have a little more cooling room but keep the 190 if mostly running empty.



jjw

ND

 

[fj40charles]

I don't think you want oil temps to be below 212 degrees. I spoke to Cummins and they said there is a thermostat for the oil and it is supposed to open above 212*. The reasoning for a hotter oil to keep moisture out of the oil. He said the oil temperature was independent of the water temperature.



Charles