How "hot" should I be running?
 

Background:

My truck would start to get hot when idling. I never actually overheated, but it would get right up to the line if I sat too long. While driving, the temp gauge stayed around the "M" in NORMAL.

My coolant would also disappear after a little driving, I'd have to fill it up. It was spewing lightly out of where the hose connects to the radiator, causing a small puddle on the drivers side, up at the front of the truck.

So, thinking my thermostat might be stuck, I replaced it, the therm housing and also the coolant temp sender, cause I broke it. I replaced it with the OEM temp, not the 160f they try to give you.

Now:

No more coolant leak! :D Not even a drop, as opposed to the puddle I had...so I obviously fixed something.

But! Even while driving them temp gauge will go to the "A" and the "L" in normal. This is even while I'm driving, which it never did before.

Now, to see if it would actually overheat, I let it idle in my driveway for a long time, and it NEVER goes past the "L". It just stays there.

Is this OK? I was thinking maybe my fan clutch before, but now it gets hotter even when driving, but not past the "L".

Could the guy before me have had a 160 thermostat in there? It never looked like it was changed though. Only have 110K on it.

The factory gauges aren't the greatest, but if you are in the "Normal" area, I suspect you'd be fine. I wouldn't get overly worried about it, but perhaps the sender is starting to go out? The best way to tell what your real temperature is, is to install an aftermarket temperature gauge.

I use a meat thermometer and place the probe inside the coloant, then you can see what you are actually running at and see what the gauge is reading to really give you a true perspective.

check the fan clucth, it probably needs to be replaced. spin the fan by hand it should have some resistance to it. usually when you run the ac is when you will notice the biggest difference if the clucth is bad.