Shell Rotella T6 5w40 no longer carries the API gas engine rating. Only Shell T6 5w30 has a mix fleet rating. Stick with oils with the SN+ and GM Dexo1 Gen2 rating for LSPI mitigation with reduced calcium levels.
Primary goal for automotive engineers today is to meet CAFE ratings. Nothing to do on which oil is better for the engine but to follow the corporate policy in meeting CAFE. That's why we see 0w16 and 0w20 recommendations here in the US yet in other parts of the world the same engines will use a...
The only reason I would buy a Colorado is for the Duramax. I prefer low end grunt vs. high end HP. That's why I'm driving a F150 with the 2.7L and not the 5.0L V8.
Personally I would only stick with tuners that retains the OAR. Won't be as aggressive power wise compared to other tuners with OAR disabled but does give extra protection if you get bad fuel, mismatched fuel or when premium isn't available.
I'm using Optimum No Rinse Wash & Wax mixed with distilled water in a spray bottle for spot cleaning.
https://optimumcarcare.com/product/optimum-no-rinse-wash-wax1
Like Forscan it's disabling the BMS hence the warning message on the display at startup. Can do the same by simply unplugging the connector from the BMS sensor on the battery.
From what I have read it actually programs the ECM much like using Forscan. So it can be removed after programming and no other intervention is required.
Should be minimal for normal driving since the turbo is liquid cooled. Little risk of bearing coking using synthetic oil. Towing is different story but A.S.S. should automatically be disabled when in Tow/Haul mode (at least it does on the F150). With that said I did disable A.S.S. on my truck.
I put around 160k miles on a 1990 Supercab with the 4.0L and never had that issue. Only issues I had is with the valve covers leaking, A/C lines leaking and the rear ABS module failing.