Kia Carnival 2006 Problems

YOUR method of checking fuel consumption isn't very accurate, so it's hard to comment. On the basis of the distance you cover on a tankful of fuel, you're using 16-18 litres/100km, which is high if that's accurate. The Carnival is a big lump of a vehicle, but should get about 12 litres/100km, which would give you a range of at least 600km. Overheating was a fairly common problem covered by warranty, but it would be worth making sure the engine didn't sustain any more substantial damage in the incident that might be affecting it.

THE Kia Carnival is the least reliable, having well-documented problems with head gaskets. I would be drawn towards the Honda because it's well-built, well-designed and more contemporary than the Mazda.