Could be the serpentine belt rubbing on something, but is probably a bearing problem in the belt idler pulley. However, it could be the power steering pump, AC compressor clutch or generator. As the water pump is at the opposite end of the engine, it's probably not that.
Two cooling fans controlled by three relay's . If only one fan is working ,that could be a problem .
Coolant Level Sensor Description
The coolant level sensor monitors the coolant level in the cooling system and indicates if the coolant is low. This sensor is located at the base of the radiator surge tank and is not serviceable.
CHECK COOLANT LEVEL (2)
The IPC receives a discrete input from the engine coolant level switch. The engine coolant level switch is normally closed. When the engine coolant is low, the engine coolant level switch opens. When the IPC receives an open signal from the engine coolant level switch, the IPC displays the message on the DIC.
Relay Driven Dual Cooling Fan Diagnostics There are using a pontiac , by your cadillac is the same .
This problem is out side the gas tank , has nothing to do with the fuel pump or fuel level sending unit inside the gas tank .DTC P0446 EVAP Vent Solenoid Valve Control System . Do you know anything about automotive evaporative emission system ?
Wells EVAP Training with Sgt Tech P0440 P0441 P0442 etc
This DTC tests the evaporative emission (EVAP) system for a restricted or blocked EVAP vent path. The control module commands the EVAP canister purge solenoid Open and the EVAP canister vent solenoid Closed. This allows vacuum to be applied to the EVAP system. Once a calibrated vacuum level has been reached, the control module commands the EVAP canister purge solenoid Closed and the EVAP canister vent solenoid Open. The control module monitors the fuel tank pressure (FTP) sensor for a decrease in vacuum. If the vacuum does not decrease to near 0 inches H2O in a calibrated time, this DTC sets.
Is it antifreeze or just water? If water, your AC system will frost up under use, which will melt and pool under the car on the passenger side (normal) after the engine stops. If antifreeze, there is a complicated cooling hose system, with some of them near the firewall. Check the overflow tank to see if you are losing coolant, and if so, check the hoses there while the engine is running.
Your security system may be causing a problem? Any applicable trouble codes? To check codes, yourself, at the least, you need an obd2 code reader.
Is there a security lamp on the dash that is staying on? There might be a relearn procedure you could try if it is a security system issue?
Are you sure its oil? If you bought it used someone probably added Bars Leak or some other cooling system sealer which can appear as oil. Cadillac Northstar engines are well known for cooling system problems, and that is usually the first step people take. If it is oil that could indicate an intake manifold leak or a head gasket leak, although it usually results in coolant in the oil, not the other way around.
Try cleaning the throttle plate first . I wouldn't just change the IAC valve without testing , hooking up a scan tool that show engine data.
A few different thing's could cause high idle .The idea is to test all thing's that could cause a high idle till you find the problem. Vacuum leaks , throttle plate sticking because it's gummed up with carbon , varnish build up . Or is the PCM/ECM making it idle that hight etc... Is the throttle cable bound up.
Throttle Position Sensor Replacement
Remove the idle air control (IAC) electrical connector (1) from the IAC sensor (4).
Remove the manifold absolute pressure (MAP) sensor electrical connector from the MAP sensor.
Remove the water pump belt cover.
Remove the TP sensor retaining screws electrical connector (2) from the TP sensor (3).
Remove the TP sensor electrical connector (2) from the TP sensor (3).
May have video on youtube showing how to
TAKE BATTERY TO AUTO PARTS STORE FOR A LOAD TEST PROCEDURE, MAKE SURE THE CASE IT IS PUT IN HAS THE DOOR CLOSED FOR YOUR SAFETY, BATTERIES SOMETIMES DO "EXPLODE" AND ACID FLYING IS NOT GOOD. IF BATTERY IS NOT GOOD, I WILL SUGGEST YOUR BUY AN AMPHOROUS SOLAR POWERED BATTERY CHARGING PANEL, THEY COST BOUT 30 BUCKS AND WILL KEEP YOUR BATTERY CHARGED UP OVER LONG PERIODS OF TIME.
How hot does it get in degrees F?
Have you ever changed the thermostat? Can you checK coolant flow through the radiator? Check for combustion gases in the coolant? Does it overheat going down the highway or at idle?
