How do you replace timing chain marks on a 94 Cadillac Eldorado?

To replace the timing chain marks on a 1994 Cadillac Eldorado, first, ensure the engine is at top dead center (TDC) on the compression stroke of the first cylinder. Remove the timing chain cover and inspect the timing chain and gears for wear. Align the marks on the timing gears; the crankshaft mark should point at the zero on the timing cover, and the camshaft mark should align with the corresponding mark on the cam gear. Reassemble the components, ensuring everything is properly torqued and aligned before replacing the cover.