quote:1) the passenger side fan and the condenser fans start immediately when I turn the key. Is this normal?
........Some cars have one radiator fan controlled by a switch on the center console. That may be your situation. Otherwise, no, radiator fans are thermostat controlled and should not just come on with key turn.
Condenser FANS? You have more than one? Should just be the single stock yellow fan sucking air into the engine bay. That fan is controlled by the round temp control knob to the upper right of your center console. Try turning that small chrome knob counterclockwise and see if that turns off the condenser fan.
2) the coolant tank closest to the front has a 5/16 hole 1/3 down from the top and is facing the engine. Is this where the previous owner moved the sensor to the block? what is best way to plug the hole?
........yes, probably the stock temp sensor location. A trip to an auto store - NAPA - should source an appropriate brass hex-head plug for that hole
3) Last question I swear. the coolant cap located on the rear tank does not fit snug. what is the correct cap?
Correct cap is European and they differ slightly from US specs. You may find what you need at an import parts house. Most of us run 13 or 16 pound caps. Any competent radiator shop can cut off and then install a proper neck for US spec cap, if needed.
And no, that is NOT going to be your last question.
You are destined for many more questions, but that is why we are here.
Welcome to the De Tomaso Family and the P.I. forum!!
I suggest you contact the Houston Space City chapter of POCA and you'll find plenty of local hands-on support in addition to us here in cyberspace.
http://www.spacecitypanteras.com/
We want photos and more info for your car!
Larry