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Recommended thermostat opening temp

wil440
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pepsi71ocean

pepsi71ocean

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1 minute ago, Mopar1973Man said:

 

Just rise +10°F. That's all.

 

Like my idle temperature is the 172°F. Running down the pavement in a snowstorm I still saw 186 to 188°F. So if I changed for 190°F it would be idling at 182°F and running about 197°F the last I remembered. 

 

Can I ask why your running a 180 instead of a 190 then? I didn't know if this had to do with pulling grades or something of the like?

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Mopar1973Man

Mopar1973Man

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23 hours ago, pepsi71ocean said:

Can I ask why your running a 180 instead of a 190 then?

Just to experiment with the idea and see what truly happens. Any bonus, any loses, etc. So far I've not seen any huge loss of MPG other than a few tuning adjustments to gain it back. Last tank was 19.5 MPG running through a snowstorm. The only bonus I can see on this side is that you can keep the engine -10°F cooler and give more time pulling hard and heavy on a grade before it rises. That's about it. 

 

23 hours ago, pepsi71ocean said:

I didn't know if this had to do with pulling grades or something of the like?

Nope. Never had any kind of heat issues. I want to jump to a 200°F thermostat next to see if there gains or bouns on that side. 

Edited by Mopar1973Man
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wil440

wil440

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Just got around to doing water pump, belt and thermostat. I ordered  a Mopar thermostat 5202 8185AC from Rockauto 195 degree, turns out it's not right, outer circumference is too small at 2 3/32nd versus 2 1/4 so 5/32nd too small, gasket sits in the groove instead of around the thermostat and no jiggle pin, it's in, sealed and working ok but took ages to bleed, now got to find the right one..... wrong parts test my patience due to the cost and the time it takes to get stuff

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ofelas

ofelas

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58mm 24v with bypass disc, 190 degrees - 190F thermostat fully open at 207F, fan kicks in at 215F -

 

Mopar 05015708AC

Cummins 3946849

 

Both the above correct stats have a single jiggle pin, installed at 12 o'clock, as well as a rubber sealing ring around the flange.

Edited by ofelas
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pepsi71ocean

pepsi71ocean

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2 hours ago, wil440 said:

Just got around to doing water pump, belt and thermostat. I ordered  a Mopar thermostat 5202 8185AC from Rockauto 195 degree, turns out it's not right, outer circumference is too small at 2 3/32nd versus 2 1/4 so 5/32nd too small, gasket sits in the groove instead of around the thermostat and no jiggle pin, it's in, sealed and working ok but took ages to bleed, now got to find the right one..... wrong parts test my patience due to the cost and the time it takes to get stuff

 

That's what my stats did. They fit into the grove, and not on the outside of it. That grove is to seal with the gasket. Although, when i bleed the system I leave the Tstat out and put it on once I'm filling the truck up and it gets up into the top of the head. I also park my truck on a hill and angle her so that side is the highest up too.

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Mopar1973Man

Mopar1973Man

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I can tell you Gates thermostats are junk. The 200*F thermostat I got has 30* swing from cold to hot. Heats up to 208*F pops open and drops to 188*F and starts over. Hottest I seen was pulling a 6% grade at 212*F. Then the coldest is pulling in to a parking lot idling at 175*F with an outside temperature of -4*F. Really? Never settles down at all. I'll be pulling this out and dumping it. Notice to others just because its name brand thermostat doesn't mean its good. Gates is a fail in my book.

 

At least the NAPA thermostat are very stable and don't cycle like this. Typically the 190*F floats right at 195* to 197*F stable.

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NIsaacs

NIsaacs

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8 hours ago, Mopar1973Man said:

I might give this a chance yet. My trip home the swings start getting shorter back and forth. Still swinging down to 192*F and back up to 208*F back and forth. 

 

Keep in mind, during cold weather operation and low engine power output, the heater and bypass system will allow cooling below the closed point of the thermostat. Part of the problem, is, those of us with digital temp gauges see temp swings that the oem gauge wont register.

 

I finally gave up on my Napa 180* thermostat and Hayden fan clutch (2) and installed a 180 t-stat from Cummins and installed my old Mopar fan clutch. Initial runs are very promising, still too early and cool to tell for sure.

 

ofelas, has really helped me out on my overheating issue. He has had some real good suggestions, so I think we are gaining. 

 

I think the Napa t-stat was not opening far enough to heat the radiator, so no wonder my fan clutch would not engage until the engine temp was off the chart. The ECT was hot but I don't think the radiator was. I wonder if my Napa was the wrong t-stat for the application. From all my research, it appears that the disk style is 12 valve and the button type is 24 valve and fits all the way to 2018.

 

Cummins on the left and Napa on the right.

 

 

0710181048.jpg

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pepsi71ocean

pepsi71ocean

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I bought my 200F stat from Dodge using the VIN off of our 08 dodge. I haven't seen the box in years but it was a Cummins part# under the label.  But my first open every cycle is a huge swing. after that every cycle is 197-202. first one always opens around 208. BUT this is based on my SCII.

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Mopar1973Man

Mopar1973Man

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So far the two NAPA's have worked perfectly. The 180*F ran at about 186 to 188*F rather solid and never moved. The NAPA 190*F ran like 195 to 197*F pretty solid and not moving. Now the Gates that crazy thing is up and down constantly like an old 12V 180*F thermostat. Like I said the return home is a bit better but still cycling. The Gates looks just like a NAPA in design the same large mouth design. 

 

Now the Cummins on the left looks like the old school NAPA thermostats that are no longer sold. Small mouth and brass bypass plug.

0710181048.jpg

Both NAPA... You'll see that the old school NAPA thermostat looks exactly like a Cummins. The upgraded NAPA has a much wider mouth.

 

DSCF4438.JPG

 

Old on the left and new on the right...

DSCF4439.JPG

 

Again old on the left and new on the right. 

DSCF4440.JPG

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Mopar1973Man

Mopar1973Man

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This is why I suggest NOT buying a Cummins thermostat being it is exactly the same as a NAPA except the price is MUCH lower on the NAPA. I can't see paying the big money on a Cummins when it no different than the NAPA same design just way cheaper. 

 

https://www.genosgarage.com/product/gates-thermostat-34212/thermostat

 

This is what I'm running now and it sucks. Wild up and down swings in temperature. 

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pepsi71ocean

pepsi71ocean

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9 hours ago, Mopar1973Man said:

This is why I suggest NOT buying a Cummins thermostat being it is exactly the same as a NAPA except the price is MUCH lower on the NAPA. I can't see paying the big money on a Cummins when it no different than the NAPA same design just way cheaper. 

 

https://www.genosgarage.com/product/gates-thermostat-34212/thermostat

 

This is what I'm running now and it sucks. Wild up and down swings in temperature. 

 

I'm unsure why you see these wild swings, I didn't see them here, even in PA winters. Maybe its just the tstat you got?

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NIsaacs

NIsaacs

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14 hours ago, Mopar1973Man said:

This is why I suggest NOT buying a Cummins thermostat being it is exactly the same as a NAPA except the price is MUCH lower on the NAPA. I can't see paying the big money on a Cummins when it no different than the NAPA same design just way cheaper.  

 

I have always said the same thing, however, now they are not the same. My new 180* Cummins is working great. It wants to run at 183* at real light cruise and seems to open at 188*. At idle or slight down hill it will drop to 178* I have only had one good hill so far, but on that one, the fan kicked on at 197* and the ECT cooled immediately.

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Mopar1973Man

Mopar1973Man

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1 hour ago, NIsaacs said:

 

I have always said the same thing, however, now they are not the same. My new 180* Cummins is working great. It wants to run at 183* at real light cruise and seems to open at 188*. At idle or slight down hill it will drop to 178* I have only had one good hill so far, but on that one, the fan kicked on at 197* and the ECT cooled immediately.

 

I'd say that true with the Gates. Not the NAPA. Weird but true. I've still got the Gates 200*F installed.

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