Have an 06 6OH and am running an insight CTS as well as isspro EGT, FP and coolant pressure gauges. The truck has 56k and runs awesome, the gauges have me concerned. I was driving to the mtns and was running normal temps, 190 ECT and 197 EOT then all the sudden both jumped by around 30* within a couple seconds, i heard my fan kick into high gear (thermostat must've fully opened) and temps went down to like 170* after that. The engine was under load as we were climbing a steady 10% grade, not towing but it was pretty steep. This only happened once.
The truck pukes coolant on and off and I have replaced the degas cap twice with an autozone cap. It never pukes too much but i keep the coolant just under the min line. Oh, and I'm running EC-1.
My coolant gauge steadily works its way up to 18 psi under load where I sit most of the time between 16-18psi. I have no other normal symptoms... Not losing coolant, no smoke in exhaust, no leaking exhaust, no tea-kettle whistle, and my deltas never exceed 10.
Could I be looking at HG, EGR, or oil cooler failure? Main concern is my coolant pressure as I think the degas cap is the only thing holding the system at a safe pressure.... Reading on this site has me wanting to buy a bulletproof system and stud my truck. I would prefer to do a BP EGR cooler, stock Oil cooler and not have to do studs if possible. I'm 24 and on a tight budget!
(saving for a house) Also want to get this done before i have a mortgage payment rather than ignore it and incur the cost when i can't afford it!