I usually set the thermostat at 68 and it keeps the car comfortable for the last 2 years. Even if its 20 degrees it gets nice and toasty warm. Today the heat just cut out- the heater fan blower is working but even if I put it on high and up to 80 it’s just luke-warm. When I got home after a 50 mile trip I opened the hood and the reserve was up to full but when the radiator cap was ice cold and the radiator was also ice cold. The hose coming out of the radiator was very hot. The car temperature gauge was normal. Does any one have an idea what’s wrong? Tomorrow ill be bringing it back to the dealer, I am very mad about this plus the power steering pump is leaking again, ever since I got it its been drip marks from the power steering pump and they replaced it twice already.

 

My guess would be a blend flap problem.

The radiator is likely to be cold in the winter.
If you had a bad thermostat, the temp gauge would be high.
Water pump problem would have the engine overheat.

Brett

 

A bad thermostat can also show low engine temp - as in the thermostat stuck open

Happened to my honda van once - luke warm heat - engine temp okay at idle, but at highway speeds - the engine temp was running too cool

 

The temperature gage in the cars being sold now are virtually useless. They are more like an idiot light, but with a pointer. Did you ever notice that once the engine warms up the needle never moves? In my 87 Olds 98 with a true temp gage, you can see when the thermostat opens and closes, but in the TL, it's like it it glued on the face of the gage once it reaches operating temperature.

What was said above about the flap is the most likely problem. Maybe the motor doesn't work or the a/c system is not sending the correct signal.

Only the dealer can tell for sure.