The 1.4L LUJ/LUV engine is prone to timing chain elongation, especially with infrequent oil changes. Symptoms: metallic rattle on cold start lasting more than a few seconds. Repair is $800–$1,400 and effectively mandatory once rattle begins.
Cold-start the engine with hood open. Any metallic chain rattle lasting >3 seconds = walk away or negotiate hard. Ask for all oil change records.
Est. cost: $800–$1,400 timing chain kit + labor
Source: GM TSB #PIP5555 / widespread 1.4T owner reports