2000 NISSAN FRONTIER SOMETIMES OVERHATING

Have you changed out the thermostat?

Have you taken ALL your keys to a dealer,
to see if they have to be reprogrammed,
now you have a different ignition cylinder, etc

Sort of guessing here, but that is what my 3 week old
2014 Nissan Frontier Owners Manual say's

I would call the parts dept & ask

The first thing you need to do is have the engine control modules fault codes read. DON'T GUESS.

Nissan markets its D22 and D40 pickup trucks in North America as the Frontier. A six-cylinder 3.3-liter engine with a double overhead camshaft is standard for the D22 models. The timing belt for this engine keeps the camshafts synchronized with the camshaft, enabling the engine to run smoothly. The timing belt has a limited lifetime, and typically requires replacement after 60,000 miles.----------------------------------------------------------------------------------------------
Original Launch CResetter

Timing belt

i know all about the vegas heat. i live in henderson. the alternator is going out. the regulator is internal so you have to replace the whole alternator.

I've had problems with Datsun (later Nissan) engines hanging the closed thermostat until it boiled, then the thermostat released and operated normally. If you increase the small vent hole in the thermostat valve plate a small amount, the problem disappears. It seems that steam from engine operation gathers behind the thermostat sensing bulb and delays opening. The increase in vent hole size lets the steam through and allows the hot water to open the valve. Hope this helps!

Chk the belts, air in the tires. Stop at circle k and grab a 12 pack of pepsi a bag of chips and make sure your cell phone won't rape you for roaming. It's a good 4 dsy drive so sleep in motels, brush your teeth and shower daily. Just kidding . I drove that in 10/02 by myself in a 96 ford escort. Puked a timing belt at cooksville, Tenn on the way back. I took 40 back because of the weather on I-80 this time of the yearEnjoy Oh, did you top off both pumpkins and the t-case?Get that fuel thing fixed and put it to the wind.

Try replacing the coolant temp sensor. Get the one from the dealer. The others do not fix the problem.

If you are loosing water then your radiator is bad.