Cadillac CTS First Generation Forum - 2003 - 2007 Discussion, 2007 3.6 Engine Noise and Code P0024 in Cadillac CTS Coupe, Sport Sedan and Sport Wagon Forums; Engine was seized due to low oil. Got it loose and running with a knocking noise (piston slap?) and code ...
Engine was seized due to low oil. Got it loose and running with a knocking noise (piston slap?) and code P0024 set (Exhaust timing bank 1 24%).
Pulled front cover to check timing chains. Nothing amiss (was changed at 10k miles now has 40k) with chains and sprockets. Found aluminum flakes in each of the VVT solenoid valve screens more on right side.
Pulled and disassembled oil pump. OP is perfect and contained no debris. Front cover has no damage. Where is the aluminum coming from?
Probably the connecting rod bearings. They got worn down due to heat and lack of lubrication. The noise you hear is the rod banging against the bearing/crankshaft as there is too much clearance. Only fix is complete rebuild, replacement engine or new car