Well Idaho got its first now. As I type this message the snow is falling and sticking in the yard. So in a hurry this morning I got my winter 265's put on, installed the grill winter fronts, and need to change a thermostat. So is your truck ready for the winter cold and snow?I still want to crawl under check both diff's, transfer case, transmission, and grease the driveline. Then I'll think I'll be ready for old man winter.

Something you probably don't want to happen will happen over 215*

If the cooling system is designed to run under 215 then somewhere not too far past you will begin pushing water as well. All downhill from there :wtf:Nascars systems are designed for much higher pressure which allows them to run such high temps before the water boils and eventually pushes out the overflow. They also see oil temps as high as 240. Again, all in the design of the oil.

Well dang. I knew the nascars were a different animal but I was using it as an example to show that the whole world doesn't end if you go over 210. I found cummins stuff that did say 215 all over it. The 4.5l cummins has a 225 max and that thing has a 5.??" stroke. I'm thinking thats what I need to throw in my jeep.

Well dang. I knew the nascars were a different animal but I was using it as an example to show that the whole world doesn't end if you go over 210. I found cummins stuff that did say 215 all over it. The 4.5l cummins has a 225 max and that thing has a 5.??" stroke. I'm thinking thats what I need to throw in my jeep.

Yes if you could build a system to hold the higher pressure you could technically run hotter. But hotter is only better to an extent and then it begins to be detrimental. Keep in mind them nascar boys have real deep pockets they dont hesitate to scrap a 60k dollar motor after only one race! Between qualifying and practice and the race they typically see no more than 500 to 600 miles on an engine before they yank it and disassemble it for inspection.

If they are pulling them what are they replacing them with or why are they ditching them?

They are going to 180's and 190's, because they think a 200° is too hot to do any good and is emissions based. It's a simple misunderstanding. I would switch to a 200°, but it would make my fan run more and lower my economy. If I can ever reprogram my fan I would consider it.

215*F is suppose to be the Cummins limit...

The max allowed temp, per Cummins, is thermostat based. 212° is the limit for a 180° thermostat, and 225° is the limit for a 190° thermostat. A 200° thermostat should have a limit of around 235-238°. The temp the thermostat is advertised for is the opening temp, most don't go full open for about 15-17° above that, and then have a 15-20° higher max limit based on heat rejection capability.

So in theory, I think my thermostat is a 190 because it's actually from a 5.9 gasser. I can't remember but I think its 190. Anyhow. Pulling the trailer and whatnot I get up to maybe 205 on the long hill by Rolla that I fly up with the trailer to pass all the slow semis and thats on a 95F day. So thats a 15 degree gain so a 200F tstat would theoretically set me at 215. Perfect! I'm thinking it might be a little lower since the temperature differential would mean more of it dissipates in the radiator, so maybe 0.1* lower. I shall head to CF and rape them of their tstats!

Why on earth would you run a gasser thermostat? That seems like your asking for trouble.

Why on earth would you run a gasser thermostat? That seems like your asking for trouble.

That's what they gave me and I didn't realize it till I got home. Works perfect though.

a 5 or 10 degree temperature change does NOT make a 37% difference in the mechanical portion of the system. (fuel efficiency, power production etc) (We can fight that out but let's start a new thread.) What must be happening, some of the programming for the fuel and timing curve of the motor is based on "operating" temperature. As we slide in and out of this window, fueling must be changing. Where is this window and what are the parameters? Sorry I don't know more about it yet, but hope to soon. Hag