In one statement, you think you need a better radiator and then you talk about running a lower thermostat. If you are truly under cooled, putting in a lower thermostat won't help anything.

 

So the P0600 code popped up after running pretty hard on the interstate and the engine temperatures reached over 210 degrees. The truck went into limp mode so i pulled over shut it down for a few minutes and let it cool down...i fired it back up and it was fine and haven't had an issue since...even running it the same way but keeping the engine temp down with heat on in cab of truck to stay sub 200 degrees. Otherwise if it hits that 210 mark i get p0600 code/datalink comm. error.

the OTHER issue i have and can duplicate every time is that ANYTIME i let the transmission temperatures get over 210 it will indefinitely start shifting hard and do this thing where it feels like 10th gear turns into a neutral gear and then the shift indicator jumps to 1st gear but the truck doesn't actually shift to 1st gear, instead by this time i'm slowing down enough for it to find/ bump HARD into 8th or 9th. How i have solved that problem in the meantime,is to run the heater and and it will stay a whopping 30 to 35 degrees cooler easily, like around high 170s/ low 180s.... At sub 200 temperatures i can run the **** out of it with no issues.
So in my mind i thought, let me just keep it as cool as possible and i wont have issues.
At this point my brain can only think that there must be a safety switch or a sensor that doesnt like these temperatures? IDK what it is about 210 degrees or more but the truck does not like it!!

Lastly, it hasnt been over 80 degrees outside during these times....Im near Raleigh NC

 

turning the truck off usually INCREASES temps as all the fluids are now just sitting in the hot motor - nothing is being circulated, no air moving across it, no fans running etc... Turning it off is probably re-setting whatever is sending it into limp mode.

IMHO first step should be to talk to your tuner

 

I would do a 160 thermostat, external trans cooler with the PBH fittings and talk to my tuner about running the fans lower to match the thermostat.

The external trans cooler may not be needed though. The coolant thermostat alone may drop temps enough to eliminate the issue.

 

After reading through numerous threads i think it might be wise to take it to the tuner before i do anything else to it....It should be happy to operate WELL ABOVE 210 degrees and something is causing it to act stupid and its not the heat. its gotta be something in the tune or a bad sensor somewhere.

 

Two or three guys on another forum have had their Mishimoto spring a leak. It's definately not on par with their products, but it happened recently.
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