Ok gentlemen, my 200F dodge stat came in and i swapped it into the truck. This experiment is based on comparisons of the 200F Mopar stat to the 195 Napa one. I decided to take the plunge in this, and will post up pictures later from my phone showing the two T-stats. The Mopar one is definitely looks Cummins to me, and is very beefy to start with. My Mopar one cost roughly 60 bucks out the door at the stealership, im sure one can find one cheaper elsewhere. I'll also grab a part number, but there is another thread somewhere on CF that lists it. Its a 6 series though. I decided that since no one else will play with this monster i should be the first. This is in reference to this thread here http://www.cumminsforum.com/forum/98-5-02-powertrain/579307-what-kind-thermostat-best.html So far, some baseline stats. Highway speed @ 65mph, temps 184-188, IAT 89-94 @ 45. GPD @ level, 2.40Gph(aproxx) Short idle, temps 184, IAT 105-114@ 45, GPH@ .74-.80 long idle , temps 179, IAT 96-105@ 45. GPH@ .80-.90 All units are in F. Also a short idle is say a stop ligt, to up to 7Mins. Anything over 5-7 Mins is considered a long idle. thus far today since i swapped it in, (and it burped), my temps are holding a stead 200-203F, idle gph was between .54 and .67! Thats amazing. Now we should also note that the scan guage that im using also is calibrated for the current running MPG. i expect this to change. I also took a short trip this afternoon. and we shall see over the next week or so how the temperatures handle. Tonight will be the first night of idling to say after i get to work, so we shall see.

I just installed the 200°F thermostat today($73 from the dealership!!) and the heat definitely blows a bit hotter, which is good because it's gonna be a looong cold winter.

Wow! I was quoted $56 from my local dealer. JR

Wow! I was quoted $56 from my local dealer. JR

I'm in Canada though, everything is more here...

I have started to buy sensors etc. directly from Cummins Canada. They are very reasonable (so far) and they have been able to ship the same day (usually by Greyhound bus) resulting in very short wait. To compare, Cummins is usually 1/3 to 1/4 the price of what autoparts store and dealers charge.

Hey guys,

Long time no post. But I though I would give an update.

Turns out that the problem was a bad cross over tube. So I've been up and running this whole time. I put on about 5,000 miles and all of my tanks were over 17.

I will resume once I install the new toys I bought, a set of intercooler boots and the high idle fooler kit as well.

Hey guys, I though I would bring this thread back to life. I replaced my 5 hole 60 hp injectors with some 7 hole 100's. With over 5,000 miles on the truck since I can say I have not lost mpg, but gained driveability.

Over the winter I still had a timing knock. Then I borrowed injector lines tried that. And then I did a compression test. The range was 400-450 cold, and the weak cylinder was no4. However, in the end I still was losing prime. I then bought all new crossover tubes and that fixed my problems. The truck Sat for two months and fired right up when I needed it.

Then over the winter my stalling issues have just about all disappeared. With discussion with Mike, we concluded that the 5 hole 60's were not atomization the fuel in the cold sufficiently. And as a result the 7 hole 100's do.

With multiple sub zero nights unplugged I was able to get in and drive with no issues.

I have issues still, I bought intercooler boots because under load I hear the whistle, but I can pressure test my system with the air compressor and get no noises. Dumb founded.

I also bought Ed' s high idle kit and plan to run the mpg fooler this winter. I tested it with a resistor last winter, but we will see this winter how is goes.

I will start tracking updates again, but I can say that I have yet to have a bad tank of fuel.

Are you running a 200 stat during the summer?

I ran a 200 stat all winter with the coldest temps in 30+ years and I would say it made a positive difference in a few areas but as soon as we began seeing temps in the 60's this spring I swapped it back for my 190. When pulling heavy I would see temps rise to 202-205. Being the fan locks up at 205, I think it's counter productive to run the hotter stat in warm weather.

I've run my 200 all summer. My fan only locks at about 210 tho.

subscribed

I'm going to follow this one as well, thanks for taking one for the team Pepsi!

 

Dave

I just threw one in last night.

I decided I needed a new thermostat because it was taking forever to get the engine warm.

With freezing temps here in Asheville, NC, Heat is essential.

I drove it to the store to grab a few things afterwards and the temp jumped to 160 ish by the time I got there.

This morning about the samething happened, granted it was much warmer.

I have driven those temps for a month or so now and it has not warmed up that fast.

 

The first thing that I noticed when I went to replace it was there are no holes in my 200 F thermostat like there were in the 180 F when I pulled it out.

I was right that there was water flowing through my radiator while it was warming up and that was why it was taking so long to warm up.

I just thought that it was staying open, but no, there are holes in the damn thing making it happen.

 

I have driven it four times since I replaced it and my truck warmed up in under 25min each time to about 194 F on the stock temp gage.

 

Definitely recommend it for winter if not year round so far!

 

Edited for grammer ;~P

Edited November 26, 201410 yr by eddielee

Can someone post a Cummins or other part number for the 200 degree thermostat?  It would be much appreciated.  I will see what I can find. 

This is the Cummins part number I came up with. 

 

4929642

Oooops!  It looks like the above is the 180 degree thermostat.  Apparently the 200 degree thermostat is P/N 4990285.

Just order a t-stat for a 2012 6.7 I do believe is the year

Edited November 27, 201410 yr by mopartechnician

I had to order mine from Napa online or order at the store. 2010-2012 6.7L is make specific. Must specify temp 200F

Edited November 27, 201410 yr by eddielee

Here you go NAPA listing at least.

http://www.napaonline.com/Catalog/CatalogItemDetail.aspx/Thermostat-OE-Exact/_/R-THM456200_0420240722

The day I bought my truck it was around 40 degrees outside and I drove it home 4 hours, temp never really broke about the 160 mark on the factory gauge. I made a winter front that covers just the radiator and my temps still only read around 165-170 with normal driving. A few trips down the interstate at 68-72mph and I can reach 180 ish but on my return trips the temp wont break 165. I bought a 190 thermostat from napa last week but havent had time to install it, after reading this I'll probably spring for the 200* instead. I usually fill up about half a tank (about 300 miles) and my mpg's have been steady a 15 to 17 (hand calculated). Its been in the teens and single didgets in the mornings, and I usually let the truck high idle before I leave in the mornings and before I leave work in the afternoon.   Maybe Friday I'll take a drive out to Cummins and pickup a 200* thermostat and see what kind of a difference that makes.

I have got to replace the tstat in the wife's truck.  I used it to haul a load of 8 55 gallon barrels (about 3,400 lbs.) full of sugar the other day.  Even with the Winter front louvers on the grill and in 5th gear with the pedal to the floor, I had a very difficult time getting the engine to reach full operating temperature and when I back off the power on level ground, the engine temperature would drop down below what I estimate to be 160 degrees on the temperature guage. 

 

On the other hand, I got an opportunity to go along as a driver and helper to pick up the sugar.  We rented a GMC long box truck equipped with the Duramax diesel and Allison automatic transmission.  We loaded 40 55 gallon barrels of sugar (17,000 lbs.)  The engine temp stayed pegged at about 190 even when we climbed up the mountains coming out of South Pittsburg, TN where I had the pedal to the floor for about half hour holding about 50 mph.  I wish our Cummins engines and thermostats had temperature consistency and control like that.  Even though the Duramax in the rental truck was derated and the transmission had torque limiting (or at least appeared to) for initial take off in 1st gear, I was very impressed with how it performed.  I still prefer my Cummins as the Duramax is a complicated and cramped mess to work on in my opinion. 

 

Driving a vehicle with that much weight, mass, and forward momentum and NO exhaust brake was a TOTALLY new experience but that is a topic for another post.

You need to keep in mind that on most vehicles anymore the guages are nothing more that idiot guages, in other words they are programmed to show a certain point as long as the range is what is expected. As an example, the oil pressure guage on Michael's 24 valve truck will rise when the switch is flipped fooling the ECM into thinking it is cold outside and drop back down at the flip of a switch. I remember the video on here, but can't find it.