firstmustang90

I have a 90 5.0 lx last fall it just stopped getting to operating temp. I changed the thermostat, fan and clutch,rad. cap and new coolant. tried cardboard in the winter months still now change. temp gauge bearly touches the L in normal and only blows luke warm air. any ideas would help.

stdyhand

I would check the thermostat again. Just because you replaced it doesn't mean it was/is working properly. Pull it out and boil it. Check the water with a theremometer and watch for the thermostat to open at the correct operating temperature (likely printed somewhere on the thermostat).

If it isn't getting to operating temperature your thermostat must be stuck open.

I would say your gauge could be wrong also, but you said it doesn't blow anything but luke warm air. That's a common sign of the engine only reaching a certain temperature because the water is constantly flowing through the stat.

Bubba 95SN

Heater core plugged, gauge inaccurate? Something to consider if the upper radiator hose is hot? Did not state if tried to check hose. Of course recheck thermostat, brand new box bad part.