Hi there Black XJ
I have recently purchased an 07 JK CRD with 70,000. I t has had a few issues the kind you expect with a 5 year old car. Other issues have been far more specific to the JK.
Check this link it goes through most of the issues with a CRD; if you’re buying petrol I can’t help you much.
http://www.lostjeeps.com/forum/phpBB...hp?f=5&t=54207
Assume the ball joints will need replacing on any second hand JK they suck ass. Easy but time consuming DIY for approx. $400. Buy the ball joint press from the US 80 and synergy ball joints. Follow the you tube vids. I would recommend doing this first cab off the rank and just assume they are buggered.
Next big one is if the vehicle is lifted check the front drive shaft CV boot at the transfer case. If its torn negotiate that into the price as an aftermarket shaft will be on the cards. Same goes for the rear. If they have never disconnected the sway bar its prob not an issue.
If you can test drive it take it to the car wash and hose the roof of the old girl down or run her through the car wash, the hard tops love to leak.
Any clicking or banging as you dry steer will also indicate front end issues another common problem with the JK's is anything that uses a ball joint; tie rod ends drag links as mentioned in previous post also have issues.
If your looking at the pentastar in a new model ists a great donk. As for the older engines go the CRD it’s a farm more tried and tested engine. Been used in Europe for ages.
That’s about it, you’re going to get issues with any vehicle. If you buy patrol or cruiser you will prob get less as they are better built but value for money the JK is excellent But you do get what you pay for at the end of the day.