“If you can pull rust chunks out of the frame [on a TJ], then you should do either a frame repair or a frame swap.” Jeep Wrangler TJ Forum · 7 years ago What To Look For When Buying A Used Jeep Wrangler!!
: Look for water damage on the interior roof or floorboards, indicating leaking seals. Reliability by Generation Generation Key Focus Areas YJ 1986–1995 Frame rust at shackle mounts, 4-cylinder power limitations. TJ 1997–2006
: Use a flashlight to check the engine "valley" below the oil filter for oil residue from a potentially failing oil cooler housing. Check for radiator and thermostat housing leaks.
Buying a used Jeep Wrangler is unique because of how these vehicles are often used off-road. A proper inspection requires looking beyond the engine to the structural integrity of the frame and the quality of any modifications. Engine Integrity :
: Always test that the Jeep shifts smoothly into and out of 4-High and 4-Low . If equipped, test the lockers and sway bar disconnect.
: Listen for unusual noises during the test drive.
: Inspect for rips, failing zippers, and yellowed plastic windows.