Where is needle pointing when it kicks on? Are you talking near top of safe zone?

Reason I ask, trying to see if mine is working. Hauled at 9,000 lbs across N.M. & AZ desert last week (95* with 20 kt headwind)...my 180 t-stat got about full needle width above 190*....seeing day light between 190* and needle...middle of nowhere, 1 am and I got a little nervous. Backed off, to 75 mph, and it cooled down to 190*. From what you and others have said, you know if it kicks on...even at cruise. I don't believe I've ever heard mine??

RJ

 

As I said, I still have the original 190 degF thermostat. When running empty, the coolant temp will run about one needle width below the 190 degF mark. When towing, it runs about one needle width above the 190 degF mark - the left side of the needle is usually touching the right side of the mark on the gauge. The engine driven fan kicks on at about 1-1/2 to 2 needle widths above the 190 degF mark. Coolant temperature has never remotely approached the end of the operating band, even when towing the 5th wheel into the Davis Mountains at 60-70 MPH in Texas summer temperatures.

Rusty

 

The fan in my truck does not sound like a 747 taking off. To me, it is the trained ear that will notice these sounds easier. Even empty, driving in 90+ weather at 70+ mph, I hear my fan cycle on and off every few minutes. I recently heard the fan come on and tried to get my girlfriend to hear it........but she couldn't pick up on the sound. If my radio is on and the a/c is on high, I'm not sure I could hear it.

Waylan

 

Well, I'm going to give the T-stat a try. I found a 180 degree 'performance' thermostat at Kragen for only $12.99. At that price it reminds me of when i was young and parts prices were reasonable.

I do think the thermostat is not opening up all the way. The fan only comes on when it it is on a long slight grade. As for how hot it is getting. My temperature gauge was going to the top of the operating range, say 20 needle widths higher than the 190 degree mark.

 

Check it out very carefully. The Cummins thermostat opens a bypass port when it closes - this circulates the coolant through the engine during warmup. Just as importantly, it closes the bypass port when it opens - this forces all the coolant through the radiator for maximum cooling when required.

If it were me, I'd spend the bucks for the genuine Cummins 180 degF thermostat, but of course that's just my opinion.

Rusty

 

Will the 180 stat have any effect on fuel mileage?
Any negative affects of having a 180 stat?

I run a 180 stat on my old chevy 6.5, does well when not pulling. but it needs about 4 of them to stay cool when I towed.

 

Crobtex,
What do you mean by flushing from the backside?

I need to pull my rad soon and spray all the gunk away too from where the puke bottle used to be. There is a definite ring there, and I'll easily go over the 190* mark while towing.
Time for a coolant change anyway.
Does anyone have the Cummins P/N for the 180* T-stat?

 

The second gen engines were upgraded to the 180, so says my local Cummins dealer. Also the OEM Cummisn thermostats no longer seal the bypass. That created a problem and I lost an engine through it malfunctioning. The upgraded thermostats no longer have the added disk on the bottom.

 

Well, then, I guess I stand corrected. I haven't run into one of these 180 degF upgraded thermostats. The last time I checked with Cummins, my 2002 still called for a 190 degF thermostat, and I think I'll keep my existing thermostat as long as I can as I really don't want hot coolant bypassing the radiator and not getting cooled.

Rusty

 

The latest thermostat that I purchased for mine is the smoothest that I have had. It does take a mile more to warm up, but is really nice on the temperatures. Mine in high humidity, air full blast, 94 degrees, heavy loads, has not yet gone over the half way mark on the gage. It is the thermostat that Cummins lists for (updated) the RV275/CPL2080 engine but is a direct replacement for the OEM on the Dodge engine. PN 3967195

 

To my knowledge there is no difference. I have seen no drop regardless of which one is in. I get 20 plus empty, no trailer, on the Dodge ECM.

 

OK Kragen's performance thermostat has the water recycle (???)port seal. No problem's with the $12.99 part. I'll put it in this weekend!

 

Look it over good, make sure the bottom cannot break off or you will lose an engine. I won't have one on my truck that blocks, to risky.

 

It doesn't take long to remove the radiator, just a bit messy, and IMHO it's the only way to get the job done right. You have to used quite a bit of degreaser (engine cleaner or easy off oven cleaner) and spray high psi water straight at the fins to get them cleaned out (or a steam cleaner would be great, but I don't have access to one). I also use the wheel cleaner spray for non coated aluminum wheels (acid) for a final cleaning and then rinse that off.

 

Checked with my dealer (I have a good one)....no TBS on changing the T-stat to 180*? I looked at the part called for on my 02 (Dodge P/N 5015708AC) and it still has the bottom disk? No temp markings, as on the Cummins, so don't know if 180* or 190*??

H.I.D. - Could you restate the problems you had with the bottom disk and how it cost you an engine? Remember reading it but not the specifics.

I bgt. and am interested in trying the 180* T-stat (3967195).....but did not install yet. Just not clear on pro & con's? Both you and Rusty make seemingly good points!


RJ