Has anyone used a 200 degree thermostat in a 13+?

[My427stang]

I posted this in another forum with no bites, wondering if anyone here had

Up to 2013, the 6.7 had a 200 degree thermostat then went to 190. Trying to chase a little more mileage and considering the 200.

I heard through internet chatter that the clutch fan may engage at 205, but haven't been able to verify. If that was the case any gains I got in combustion would go WAY out the window.

Does anyone know?

Thanks in advance

 

[Cummins12V98]

If they could have squeezed a tiny bit more economy with a 200 stat they would have. Hey give it a try and see what happens and report back.

 

[My427stang]

If they could have squeezed a tiny bit more economy with a 200 stat they would have. Hey give it a try and see what happens and report back.

Your point is valid, they actually changed from the 200 to the 190 with the changes in 2013, they must have had a reason.

I probably will still try it though and see. More to come!

 

[JR]

A very apples to oranges comparison, but I tried a 200 in my 98 (normally run a 190) last winter. Last winter was very cold, Lake Erie froze solid for the first time in 30 years so it may have skewed my results a little, but I saw a negligible difference compared to other winters. I also run a winter front from early December to early March.
I planned on running it again this winter but never got around to swapping it out. This year has been only slightly below avg temps but we are up to our eye balls in snow and I have had to run in 4wd more than usual so it probably would have been another bad year for comparison.

 

[mwilson]

Didn't the 2013 trucks have radiator shutters or something similar??? If so that would be why they dropped the thermostat temp.

 

[JR]

Didn't the 2013 trucks have radiator shutters or something similar??? If so that would be why they dropped the thermostat temp.

I could see how that could help bring the engine up to temp faster in cold weather, but the stat should ultimately control the temps the engine runs regardless of ambient temps? My truck will maintain temp once it gets there regardless of whether or not I run a winter front, it just takes it longer to get there without one especially in sub zero weather.
I thought the shutters were as much for helping to control IC temps as anything, but that might not be the case.

 

[mwilson]

I know that in the big truck realm there is a sequence of events involving fan temp controls, shutterstats and thermostats. There has to be at least 10 degrees in variation between each component in sequence. Getting any closer than that results in rapid cycling of everything involved.

Mike.

 

[smokemifugotem]

someone please correct me if i'm wrong. but isn't the winter radiator shield a waste of time since the thermostat slows radiator coolant flow to a crawl anyway when the coolant temp gets too low?

 

[EDankievitch]

The winter cover helps to slow the rapid flux in temps each time the "T" stat opens and closes. With the two large Rad's out front on the 13's and newer trucks full of cold coolant you really notice when the "T" stat opens and it sucks the engine heat away. I would notice that my heat temp would get hot in the cab to the point I would lower the setting then when the T stat would open it'd cool down. Up and down I'd always be adjusting the temp setting on a long trip. With the winter cover on I don't find my self doing the temp adjustment dance as much even on the coldest days. Oh and it does help things warm up a bit faster.

 

[Hoefler]

Also, maintains a more consistent under hood temperature for other components not cooled or heated by the coolant.

 

[rynosback]

Let me start off by saying that I'm not an engineer. But I believe there is a reason for why they put what they put into our trucks. I mean it is not like the only thermostat they had laying on the shelf when building this truck was a 190 degree thermostat. They choose that for a multitude of reasons.

 

[My427stang]

Let me start off by saying that I'm not an engineer. But I believe there is a reason for why they put what they put into our trucks. I mean it is not like the only thermostat they had laying on the shelf when building this truck was a 190 degree thermostat. They choose that for a multitude of reasons.

I am not sure it is a "multitude" of reasons, but if there is a required sequence of shutter, thermostat, fan clutch, that would be a good enough one. Diesels like heat, but if the fan stays engaged, or regularly cycles, that drag will far outweigh any benefits.

As an engine builder and gasoline EFI programmer (on the side now for 20 years after joining the military) I like to find out why, because sometimes there isn't as much thought as you'd think. The big truck fan comments above were good ones which I never thought of and likely correct.

I do think you are correct overall though, there is likely something that the truck may not like at the hot end of what a 200 thermostat will do, but heck I found a solid 1 mpg over every fill up for 2 months now with a valve adjustment slightly "out of specs" per procedure, but in specs by the numbers.

I'll likely try it, and if something acts odd I'll clear the codes and swap it back Good thing right now is that I have a very stable daily route, so I can see changes pretty easily. If the mileage or power nose dives, it'll be apparent.

Thanks everyone