Engine stays cold even at 40 degrees outside

[Kent]

It never gets above the line that reads normal I don't have a reg temp gauge on my truck (97 3/4 hd 7.3) to tell me what temp. it's running but the gauge works .

[4everlearning]

When you turn the heater on does it blow hot air?

[Kent]

Yes it works fine

[Kent]

well after I drive 5 or 6 miles

[4everlearning]

Originally Posted by Kent

well after I drive 5 or 6 miles

Thats normal. I think I would check that guage or the sending unit.
The heater wont blow hot air unless the engine is heating up. The heater gets its heat from blowing air threw the heater core that is like a little radiator that has hot coolent runing threw it.