180 deg thermostat for 2003

[LRutigliano]

I just replced the stock 190 def thermostat with the same one and my temps fluctuate from 190 to 210 or so when towing. Before it didnt run as hot. I want the pn for the 180 deg thermostat which I think is 3967195. Can anyone help to confirm the pn? Before it would only get to approx just past the 200 mark when pulling a grade and then drop down 2 needle widths below 200. Now it spikes past 200 just warming up.
Thanks
Louis

 

[Mark31]

I think the first thing I would do would be to install an aftermarket temp gauge. If an engine is running hot with a 190 thermostat, it usually will run hot with a 180. Maybe you got a bad thermostat? I wouldn't want a 180 in the winter period. Is the fan clutch engaging? Are the intercooler, radiator, condenser, "sanitary"? Maybe some of the "whiz kids" on here will chime in. Hope you find your problem(s). Mark

 

[lpennock]

I would check the fan clutch. Every time I had a problem with getting hot while towing it has been the fan clutch.

 

[LRutigliano]

Thanks for the replies... looking for confirmation on the 180 deg thermostat for a 2003 cr.

 

[Bob4x4]

Just a heads up,running a cooler than oem spec t/stat can set a dtc-too cold for too long

 

[p-Bar]

It's all about emissions run em' hotter leaner burning

 

[Prairie Dog]

If your having an over heating issue, you need to fix the cause and not band aid it with a colder stat. which can cause all kinds of problems in a computer controlled engine.
I agree that if it over heats with a 190 it will still get too hot with a 180.

 

[rscurtis]

That's correct. On my signature truck, I've never seen the fan wind up to cool just the engine, even after sitting in summer traffic. It only comes on to cool the AC condenser.

 

[Teich]

Sounds like the rad may not be full, had same issue, check the hose from rad filler neck to over flow tank also check the rad cap the little medal valve should not be loose . There is air in the rad from filling and the heating and cooling of the engine is not drawing out of over flow tank. The engine will work better with the 190* stat Laurie

 

[LRutigliano]

Lots of replies but not one regarding the question I asked... Can anyone confirm the 180 deg thermostat p/n for a 2003 CR ??

The truck is not over heating and never has. I replaced the original T-stat because its over 11 yrs old and I am going on a long 3000 mile trip with the 5er. I replaced the coolant and the T-stat (for good measure, so I don't have any issues on the trip) and now it seems to run hotter. I am using Zerex G-05 and a stock 190 T-stat from Dodge. Maybe I got a "bad" Tstat from the dealer...

Thanks,
Louis

 

[Shamp]

I cant tell you the part number, but I can tell you trying to run your engine cooler would be foolish. I will explain why so nobody else reading this gets the idea that a cooler thermostat is a good idea.

First point is diesels run about 40% thermal efficiency. That means approx. 40% heat is transferred into kinetic energy. The remaining 60% is wasted. Approximately 30% out of your exhaust and 30% out of your coolant system. If you were to lower your coolant temp all that means is you will lose more of your potential energy in the coolant system which means less mpg.

Second lowering the thermostat temp would only delay an overheating issue if you even had one. Nobody with these engines should be remotely concerned until their engine started getting above 230 degrees under load. Please notice I said under load, idling in the parking lot or hauling your lawnmower trailer is not under load. 230 under these conditions would be cause for concern. 212 is a perfect temperature, and these engine are designed to run around 212 when they are used to their potential. I know it is not that hot in western Washington but I've hauled loads in excess of 20,000 pounds and not seen my gauge go over 215-220ish.

Third point running a cooler engine can cause vaporized moisture in the crankcase to condense and result in corrosive acids and sludge in the crankcase. Also low engine temperatures will increase the emission of hydrocarbons. Basically you need temperature to boil water out of your crank. Just like how water magically condensates on the outside of a glass. It happens with an engine also.

Forth point is based on my experience as a Ag mechanic. If a problem did not exist, and you fixed something, now problem exists, first look back at what you did before you spend time and money diagnosing ghost problems. Not to sound insulting but maybe you put thermostat in backwards, maybe it was bad to begin with, maybe you did not tighten the radiator cap, low water, or improper coolant mix ratio. Coolant is a poor conductor of heat, that is why a 50/50 mix with water is used.

 

[Shadrach]

Lots of replies but not one regarding the question I asked... Can anyone confirm the 180 deg thermostat p/n for a 2003 CR ??

I'll check it out for you. Hope to have an answer for you soon. David

 

[Regcabguy]

Don't diesels in really cold conditions like Canada or northern states run cool for months at a time without a cold weather front?

 

[Shadrach]

P/N 3967195 changes up to 5292742 which is a 180*F stat. David

 

[mwilson]

Hi Louis,

What was the reason for the thermostat change in the first place?? Preventative??? Or was there an issue??

Mike.

 

[Shadrach]

I just went and grabbed a 5292742 off the shelf and it is a 180*F and is 58mm. Seem there is some mis information in the Cummins parts catalogue. I don't know why the p/n changed. They don't tell us. 5292742 is for a 98.5-99 ISB. The rubber seal that goes around the stat is slightly different in the HPCR vs the earlier ISB. The 03 and newer seal has a slight step on the top and bottom of it.

BTW There are 9 current p/n listed for stats for the Dodge/Cummins over the years. David

 

[JJPage]

Now it spikes past 200 just warming up.
Thanks
Louis

I wish my 03 would have done that...If you find out what the cause of this phenomenon is, please share, you may be holding a valuable piece of info . Jess

 

[rscurtis]

My signature truck goes to 200 and then drops back to 190 when the stat open up. It has done this for years, winter and summer.

 

[AH64ID]

OP, sounds like your replacement thermostat is faulty. Is it genuine Cummins?

I can't help with a part number, as there isn't one for a 03 to run a 180° thermostat.

A colder thermostat will decrease efficiency, power, and actually increase your chance of overheating. The fan on your 2003 is programmed around a 190° thermostat, and comes on full around 215°. A 180° thermostat had a max allowed temp, per Cummins, of 212°, so you will be above the heat rejection point before the fan turns on.

A 190° thermostat in good working order will crack at 190° +- 3° and is full open at 207°, max allowed temp is 225°. While cruising empty the temp may hit 195° and the drop at the first opening, but while towing they can hit 197-203° before dropping. It all based on the sender location in relationship to the thermostat, and the rate at which then block is heating the coolant.

 

[Mikey-KE7LBB]

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.