Q: Radiator is cold even after a motorway run,and can smell the oil getting hot.

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As above

My car has 84000 miles.
My car has an automatic transmission.

Hi there - based on the symptoms, this could either be a failed water pump (unlikely - even with no flow, conduction of heat would warm the radiator slowly), or, most likely a failed thermostat. I would also expect that the coolant temp gauge would be off the gauge on the HOT side after even a couple of minutes. As you indicate, the oil is very hot, so clearly the engine is! The thermostat on this engine is electronically controlled, and should have indicated a fault that would warn and set the Check Engine light when too hot. Check the coolant level first - a "no coolant" situation will deceptively register as cool - hot liquid makes the temp sensor work. Hot steam does not unfortunately. Check the thermostat, water pump, and for any possible coolant flow issue to the radiator (pinched hose). I would recommend a thorough inspection for overheating performed by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, give you an accurate assessment of damage and cost estimate for repairs.

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