If it is an automatic transmission, the cooler in the radiator is most likely leaking into the coolant system.
Could be a problem with the thermostat housing or it's gasket, could be a problem with intake manifold gaskets, could be a problem with heater hoses or the fittings that screw into the manifold.
Need more info. Engine coolant fan? HVAC fan? What year? What model?
could be core plugs between engine and transmission(freeze plugs)
The coolant temp. sensor could be bad....or the thermostat could be stuck shut.....there are a few things it could be actually
It will be safe to drive short distance as long as the car does not over heat. You can top up the engine coolant or use water/coolant mixture till you fix the problem which could be leaking hose pipe. leaking radiator or faulty radiator cap
Oil in the radiator indicates a possible severe problem, where coolant could also leak into the oil. Driving an engine in this situation at all could lead to severe engine damage.
Diagnostic error code number 118 with high temperature input on a Audi A4 means that the engine coolant is not running at the right temperature. When the engine is cold, it should be warm, and when the engine is warm, the temperature should be cooler in the engine. The problem could be with the Engine Coolant Temperature sensor or the vehicle could be low on fluid.
check the water pump
Check your oil and see if coolant has leaked into the engine...A known problem with 3.8L engines are defective intake manifold gaskets that allow coolant into the engine block. Costly repair.
Could be a problem with the wiring from the computer to the sensor.
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A small amount of water can be condensation, however, if it smells like or contains anti-freeze, you have a major engine problem - possibly a cracked engine block which allows the coolant to seep into the crankcase. It could also be a blown "head gasket" which is a less serious problem, but still a large job to fix. This too could allow coolant to leak into the crankcase in some cars.