96 Taurus Overheating

Problem was very intermittant and hard to diagnose for many months - took it
to shop and they couldn't duplicate the problem.
Now the problem is repeatable but I'm getting widely varying diagnoses and
costs. Maybe someone here can help...

96 Taurus, 3.0 liter V6, VIN U...In stop and go traffic the car starts to
overheat (this was intermittent for a while but now happens regularly). On
interstate the temperature is about normal but heats up rapidly when I hit
the exit ramp and slow down to 25 MPH or pull into the rest area. Some said
thermistat so I replaced that - no help. Some said clean and flush cooling
system and add fresh coolant - did that (it was time anyway) and no help.
One shop is now recommending radiator replacement at $690 (labor intensive
because front bumper/grille/headlights must be removed). One shop says
water pump but another says no because the pump isn't making any strange
noises. All have done a pressure test and say that is fine. This model
Taurus uses coolant reservior so their's no radiator cap on the radiator to
be able to visually look inside the radiator.

Here's some things I've noticed -
1) upper radiator hose from thermistat to radiator is hot and pressurized at
normal or elevated operating temp
2) according to one mechanic the lower radiator hose from radiator to water
pump seems significantly cooler than it should be (I can't reach it) at
normal or elevated operating temp. This suggests restricted flow through the
radiator.
3) heater hose is hot near water pump but cools rapidly as it approaches the
firewall
4) if I turn on the heater after the car warms up it starts blowing warm
air, but usually cools down to approximately 80 degrees within about 2-3
minutes - the faster the car is moving the faster it cools off. If I turn
off heater and adjust temp back to low for a while, then turn heater back on
and adjust temp to high, it starts blowing warm air and cools rapidly again.
5) this car uses 2 electric fans on radiator and both "appear" to be
functioning normally.

Thanks in advance for your help,

Phil

Phil Nospam wrote:
>
> Problem was very intermittant and hard to diagnose for many months - took it
> to shop and they couldn't duplicate the problem.
> Now the problem is repeatable but I'm getting widely varying diagnoses and
> costs. Maybe someone here can help...
>
> 96 Taurus, 3.0 liter V6, VIN U...In stop and go traffic the car starts to
> overheat (this was intermittent for a while but now happens regularly). On
> interstate the temperature is about normal but heats up rapidly when I hit
> the exit ramp and slow down to 25 MPH or pull into the rest area. Some said
> thermistat so I replaced that - no help. Some said clean and flush cooling
> system and add fresh coolant - did that (it was time anyway) and no help.
> One shop is now recommending radiator replacement at $690 (labor intensive
> because front bumper/grille/headlights must be removed). One shop says
> water pump but another says no because the pump isn't making any strange
> noises. All have done a pressure test and say that is fine. This model
> Taurus uses coolant reservior so their's no radiator cap on the radiator to
> be able to visually look inside the radiator.
>
> Here's some things I've noticed -
> 1) upper radiator hose from thermistat to radiator is hot and pressurized at
> normal or elevated operating temp
> 2) according to one mechanic the lower radiator hose from radiator to water
> pump seems significantly cooler than it should be (I can't reach it) at
> normal or elevated operating temp. This suggests restricted flow through the
> radiator.
> 3) heater hose is hot near water pump but cools rapidly as it approaches the
> firewall
> 4) if I turn on the heater after the car warms up it starts blowing warm
> air, but usually cools down to approximately 80 degrees within about 2-3
> minutes - the faster the car is moving the faster it cools off. If I turn
> off heater and adjust temp back to low for a while, then turn heater back on
> and adjust temp to high, it starts blowing warm air and cools rapidly again.
> 5) this car uses 2 electric fans on radiator and both "appear" to be
> functioning normally.
>
> Thanks in advance for your help,
>
> Phil

It's an airflow or liquid flow problem. Since it runs at normal temp on highway,
but heats up when slowing down, I'm betting on the fan controller or the
condenser fins are mashed down, impeding normal airflow. You might also try a
new pressure cap on the coolant reservoir.