Say hey, it's probably the thermostat. If tha't not it then it's the radiator core plugged up or the water pump (doubtful). I'm betting on the t-stat. If it doesn't open, the coolant in the block just percolates away. Be careful with the MK103, hi heat is flirting with a blown head gasket..
2000 Dodge Grand Caravan SE
No matter what you fix, there will always be something else to fix..
"Warranty" is just another way of postponing the inevitable.