How often do you all have to add coolant to the reservoir? I have had my 2007 for a few months now and have had to add about 1/4" to 1/2" to the reservoir twice. Is that normal? Not running hot...no issues. Most of my driving is highway and town. Not much stop and go.

 

Nope. Not normal. I drive all summer in texas heat and only add 16 oz a year

 

so...I'm losing coolant somehow. Hmmmm. I haven't noticed any leaks under the truck. Could it be the radiator cap?

 

Someone before you may have flushed the system and not got all the air out when they refilled. Just keep adding and watch for drips under the truck and also watch the oil color. If any water is getting into the engine, the oil will get a muddy or milky appearance.
Doesn't really sound like there is a problem tho.

 

I just had the oil analyzed and no coolant. So I will keep an eye on the ground. Thanks.

 

Testing the radiator cap would be a good idea. If it's bad, it will allow the system to loose pressure, that lowers the systems boiling point and the coolant will turn into a vapor. The coolant vapor will then seep out from the radiator cap causing the coolant level to become low.

The only other way for the system to become low is, if it were leaking (you would see coolant drips on your driveway) or coolant is leaking into the motor (an oil analysis would determine that which you've already done). So, if neither of the above is happening and your coolant hasn't been recently serviced (as mentioned in another post air pockets can develop during service causing the coolant level to become low), more then likely the radiator cap is bad.

 

Other possibilities. Old coolant is boiling because it needs replaced, or maybe the water pump is seeping from the weep hole which would mean it needed replaced.
Most people kinda forget about changing the coolant so odds are it needs replaced anyway.....
G05 is the coolant it requires btw, unless you want to get the motorcraft gold.
I'd probably do a flush and then refill new stuff and see what happens.

 

probably needs it. I guess I need to learn how to do that myself.

 

Coolant flushes are a piece of cake. Probably the first thing I ever did as a novice backyard mechanic. A little research on here and you will be good to go!

 

I saw a how to on another site that showed connecting a tube to a spout and loosening a plastic valve. Also, remove radiator cap prior. Spout and valve are suppose to be on passenger side of radiator...Sound right?