Slow to rapid coolant rise after engine is shut off

Below is a picture of the late OHV Ford Vulcan engine used in 90% of this year of Taurus. Note the valve cover design

Security light came on and shut engine down to protect engine from overheat and damage motor. Have coolant system burped. (Have all air expelled in coolant system and this should solve your problem) There is obviously air in system not allowing coolant to flow freely, which would cause rapid temp. rise and shut engine down. Hope this helps.

pop hood and look for sticker with info on the car , note most taurus come with 3.0 v6 some are [ohv]-over head valve , or [ohc] over head cam look at vale covers it should read 3.0 and witch ever ohv\ohc

fuse #9 protects the 2 cooling fan relays.

It looks like the hgh speed cooling fan realy is in a thin box mounted sideways between the battery and fender.

It has high speed relay, autolamp relay, autolamp headlamp relay, horn relay, washer motor relay, wiper hi/lo relay, wiper park relay.

Section 03-03: Engine Cooling 1999 Taurus, Sable Workshop Manual
DESCRIPTION AND OPERATION Electrical System NOTE: With A/C ON, the cooling fan motors will run continuously. Cooling fan motors will not cycle ON and OFF with A/C clutch (2884) .

NOTE: An exception to this is when vehicle speed is over 61 km/h (38 mph) and coolant temperature is below 100°C (212°F), and A/C head pressure is below 1.71 MPA (250 psi). The cooling fan motors will then automatically shut off.

The cooling fan motors are mounted within a fan shroud (8146) behind the radiator (8005) .

Engine Cooling Fan Control CCRM Applications The PCM monitors certain parameters (such as engine coolant temperature, vehicle speed, A/C on/off status, A/C pressure, etc) to determine engine cooling fan needs. The PCM controls the fan operation through the Fan Control (FC) output (single speed fan applications) or the Low Fan Control (LFC) and High Fan Control (HFC) outputs as shown in Table 2. Although the fan control (FC), low speed fan control and high speed fan control relays are normally open relays, the FC/LFC circuit is wired through a voltage inverter inside the CCRM. The voltage inverter ensures that the PCM must turn on (ground) the FC/LFC output to turn the fan off. This is done so the cooling fan will operate in the event of an open FC/LFC circuit.

Stand-Alone Fan Control Relay Applications The PCM monitors certain parameters (such as engine coolant temperature, vehicle speed, A/C on/off status, A/C pressure, etc) to determine engine cooling fan needs. The PCM determines engine cooling fan control requirements and controls the fan operation through the Low Fan Control (LFC) and High Fan Control (HFC) outputs (Table 3).

have u bled the cooling system ?warm the car and cut the car off right before the fans come on ,let sit for 30-35 minutes,see if the coolant drops in res. if so repeat process untill coolant stops droping ,then drive car regularly if overheating stops ,but monitor it because it will drop somemore/there has been reports of new and rebuilt water pumps nt having correct propelar mounted on them/ backwards etc. if this helps let me know [email protected]

Does your ac work? When you turn on your ac, all the fan should be working at all times. See if they remain on when you are driving. If they go off. check the CCM module located in front of the vehicle, it is a metallic box usually black in color not to far from the radiator. I can't remember if it was the right side or left side of the radiator. The inside of that box has electronic circuit which also drive the compressor directly. You really can't test this box, the only thing you can do is visually check it for burnt components inside. I had to repair this box on my 96 taurus because a transistor inside was open that drive the compressor clutch solenoid. I belive this box also controls the fan. Unplug the connection to this box, to see if it affects the fan by turning it off or on. Make sure the key is on tho. when you check it.

Looking at a wiring diagram I see two relay's that control the cooling fans (has two ) High speed cooling fan relay , low speed cooling fan relay . Both relays are controlled by the PCM - engine computer . Your best bet , have it checked for DTC'S - diagnostic trouble codes . Could have control circuit problems .There are videos on youtube test relay controlled circuits . How to test at the relay base (where relay plugs into ) Test power an grounds an control . Do you know how the cooling fans work ? Coolant temp. sensor inputs temp to PCM . When coolant temp reach's 200 to 220 , the PCM will energize the relay's low speed then high if temp fails to come down . Can check this data on a good scan tool . Can even turn the fans on with a good scan tool .

As you've stated driving around town it's fine, and everything is working well. For the symptoms, there are 2 possible causes:
1. Your cooling fans are not working.
2. Your radiator needs to be replaced.
I'm sure you can determine which it is, and I wish you luck on your repair.

Normal. This is called heat soak. When you stop the engine, its temperature rises since the coolant is no longer being circulated by the water pump through the radiator. The coolant then expands and goes higher in the overflow tank. As the engine cools, it retreats back into the engine. Proper level should be determined only when the engine is cool.

You will overheat the engine if losing coolant.Firstly replace the cap with a new one,Is the engine temperature normal when you stop ? If its over temperature it will still blow out coolant. Check the radiator for blockage of the tubes & ensure the fan belts and water pump are in good order. Worst case is a blown head gasket can test for combustion gases in the coolant