As posted in the oil change thread. I'm a believer in engine flushing at regular intervals, keeps the sludge away and frees up carbon deposits. May even clean the PCV system. Used only 1/2 the quart bottle to top off dipstick, idled for 15 minutes, drained hot. With the 15W40 the oil pressure gauge is noticably higher at idle, just below 50 indicated.
Also removed and cleaned the throttle body, added Techton to fuel tank.
2012 CTS 3.0 61,000 miles
Tip: spray clean, dry, then grease the oil canister threads, oil fill cap, and drain plug.
View attachment 23519
View attachment 23520