Have a 96' I-30 with 110K. Drove 10 miles to work this morning and the temp gauge never came up, at all. Heat on max and the most I got was lukewarm air blowing.

Any clue as to what is the culprit. Thermostat? If so, would you go with Advance/Autozone parts, dealer, or other????

thanks.

Probably the thermostat. Blowing the heat full blast doesnt help the engine warm up either...

If you don't let your engine warm up for a couple of minutes before driving it, and in the meantime are trying to warm up the inside of the car, you are 1. not going to get warm very quickly; and 2. not being very nice to your engine
you should always let your engine run for a couple of minutes in the morning before driving it.
Of course all this could be blah to you, if it's only the thermostat that is broken

maybe he needs a new coolant temp sensor

I beleive its the thermostat. Thermostats are designed to break in the open position (although this doesn't always happen). If your thermostat is stuck open it will take the coolant a much longer time to heat up because it circulates through the radiater instead of just your engine block at first. This would result in your heater not working because it uses your coolant to heat the air. This would result in the cold to luke warm air that you experienced. If you left the car on long enough it should eventually still get to operating temperature. The other possibility is a clogged heater core.

Not quite.

You should let it idle for about a minute, then start driving. Everything comes up to temp much faster (that's the idea) with some easy driving compared to sitting and waiting. You want to minimize the time it is running with cold oil and fluids.

The thermostat is the problem, it is stuck open.

The thermostat controls the flow of coolant through the engine. Thermostats have a temperature at which they open. When the engine is cold the thermostat is closed, this allows the coolant in the engine to heat up. When the temperature of the coolant in the engine reaches the predetermined temperature it begins to open allowing coolant to flow to the radiator to cool down and then it flows back to the engine to cool the engine.

When a thermostat is stuck open it allows coolant to flow freely all of the time, never allowing the coolant to heat up.

On most engines the coolant flows from the bottom of the radiator through the block and heads, then back to the radiator through the upper radiator hose. At this point the coolant is at the highest temperature. The coolant then runs down the radiator and the heat is taken away from it by convection, or transfer of heat. Then the coolant makes the trip again.

The A/C system works much in the same fashion, but that is for another discussion.

It's good to see someone actually take the time and explain something like that.

Most of us just say "it's the thermostat".