Over Heating Explorer

06 Explorer w/4.0 V-6, 67K mi. Just replaced radiator, thermostat, and H2O pump. Temp gauge spikes to full hot after idling for 5+ minutes. Fluid level OK and stable. Wife complains A/C fails to blow cold when idling. Not sure I agree. Any ideas as to what may be going on?

Is the fan running while idling?

Why was this work done? Where was it done? This car seems a little young to need that much work done to it, particularly the radiator. It sounds like air is trapped in the cooling system. If it’s not that, it could be much worse. Was the car overheated? How bad? How many times?

Original radiator developed a leak, (see 2006 Ford TSB’s), I replaced the radiator and thermostat myself. I then replaced the water pump after wife said the temp gauge would shoot up to max hot, then return to normal. Thought I might have a circulation issue. Car has never actually overheated, as temp gauge would approach max high, I’d shut it down, or temp would return to normal by itself. Ideas?

The only things I can think of would be air in the cooling system or, possibly, the thermostat was installed incorrectly. Check for a bleeder valve somewhere at the top of the engine on a coolant pipe or thermostat housing. If the truck doesn’t have one, drill a small (1/16" or so) hole in the thermostat, reinstall, and refill cooling system using a “spill free funnel.” You will have to chase down a tool truck (Snap-On, Matco, or Mac) to get one, as I have never seen them for sale anywhere else, but they are cheap and worth every penny. It’s basically a large funnel that attaches to your radiator. Run the engine with the funnel about half full of coolant and the heater on full blast until the coolant in the funnel is hot. Remove the funnel and fill up your reservoir. See if that takes care of your temp issues.

Thanks for the assist. I’m going to check the thermostat, I could have pulled a bonehead move and installed it backwards.

when cold, open the rad cap. start it up. do you see coolant flowing in the rad?

if no flow check the thermostat.