I've been running my stock for some time now (the last 20k mi, trying to be easy on my rebuilt trans) and decided a couple weeks back to put my smarty back on it and run it on SW3. Here is where my problem began, if I run her hard 70mph+ or stand on it she begins to get hot and will fill the overflow tank. After seeing this I turned truck back to stock and ran it around for a week with no problems, and took to dealership and they replaced fan clutch and radiator cap. Now 3 days ago I set back to sw3 and last night on a quick run up the freeway I noticed she got hot, and guess what??? full overflow tank this morning ........ What do you guys think the problem is, and why is it I can run it stock and have no problems but on a mild tune this happens? Thanks in advance!

 

The 6.7 makes real high drive and combustion pressures. I'd personaly say your lifting the head and pressurizing the coolant with compression.

 

sounds like the hg..my bros was doing the same thing..seems common on the 6.7s

 

sounds like the head gasket to me too ,but change the radiator cap and see what that does before you tear her down

 

Sounds like head is lifting to me

 

Try running an even number such as SW2, with the timing set to default . The odd numbered tunes will add timing which will in turn increase your cylinder pressure.
What version are you running? What were your revo settings on? I hate to sound like a "me too" but it sounds like you're lifting the head.

 

Thanks for all the input! The day after my first post she started overflowing into the coolant tank at idle and the dealer was finally able to see what my problem was. They replaced the head gasket, fan clutch, radiator cap and an bunch of other stuff under warranty . I even had the crank case filter and recommended egr cleaning and all I can say is ouch.......I will be deleting everything very soon. Im waiting till the warranty runs out before I do that though. I haven't put the smarty back on her yet but when I do it will be set on SW1-3 and I'll leave all the settings set to default. Got a question though can I remove the head bolts and replace with arp's one by one?

 

Yes, the head bolts can be changed out for studs one at a time, and then retorque using the correct pattern.
Don't use SW 3 or even the SW 1, they increase timing a lot. SW 2 and4 should be safe.
My head gasket started leaking, and was only on SW1.
I have it on SW 0, until I get the HG replaced.