Rear differential failed at 3000 Ks.
Dealer fixed under warranty, but the breakdown left my wife and myself stranded in a remote location.
Exhaust system (muffler) rattle. Was like it from new. Dealer wouldn't fix during warranty period, in fact the dealer's service-man said to me "what did you expect, you got what you paid for".
Oxygen Sensor failed at 27000 Ks. Vehicle just out of warranty (just over 3 years old) when this happened. Cost me $450 to fix.
Rattle in front suspension. Like it from new. Reported to Dealer on various occasions, but it was never repaired.
Transfer case, complete failure, at 45000 Ks. Stranded me in a remote location (middle of winter) in the Snowy Mountains. Cost me over $1000 to fix.
Engine idle valve constantly required servicing/cleaning. Engine would often rev-up uncontrollably. Dealer wouldn't replace valve under warranty, just kept cleaning it.
It got to the stage where I would remove it, clean it and replace it (on the side of the road if need-be) to keep the thing going. I got very good at doing this.
Replaced hubcaps and hubcap retainers on a regular basis. Forever breaking off.
Many of the plastic items on the vehicle were very poor quality and would simply crack or powder-up.
Vehicle had low use, only had 52000 Ks when sold after 5 years and was regulary serviced and maintained.
By far the worst vehicle I've ever owned.
Very serious, expensive things went wrong.
Often had to wait for shipment of spare parts to arrive, forcing the vehicle off the road for weeks as a result.
Poor service relations, regardless of dealership. In fact some dealers often made negative comments about the product.
It got to the stage where the thing couldn't be trusted, hence toward the end I wasn't game to venture far from my mechanic.
I will never own another KIA or Korean product.
Finally, the last word from the guy who repaired the transfer case (a respected gearbox & differential specialist) who stated ~ "I love Korean vehicles especially KIA's, because we make a very good living from them. Its not so much the design of the things, its the rubbish components they use that keeps letting them down. If they would adopted better quality bearings I'd be out of business. My advice to you is get rid of it before something else fails and be assured it will".