I have a v6 3L in one of my Fords. I notice the temp gauge starting to get higher than normal (warmer) while I wait at a fast food window or just setting at an idle. Soon as I'm able to move it drops back donw into the mid range normal. 2 years ago I replaced the raditor, and had it power flushed and they replaced the thermostat and a few years ago I replaced the heater core.. what maks it get warn when not moving and cools off so instantly when moving? This a 99 motor...could it be the thermostate so soon? Suggestions?

 

Could be your fan clutch going/gone bad.

 

I guess it could be the fan clutch. Certainly worth checking.

I'd suspect the radiator also.
Did you use distilled water when filling after the radiator and heater core replacements?

 

well never thought about the fan clutch (about the only thing I haven't replaced so far), any way of testing that? Also when I had the heater core replaced a shop did the core and Ford did the radiator. Never heard of using distilled water before. What does that do?

 

Regular tap water contains dissolved minerals that can contribute to deposit formation and restricted flow in the radiator.

Distilled water is, well, just pure water.
Keep in mind, other "bottled waters" are not necessarily pure water.
You might even see something like "with dissolved minerals for improved taste".
Pure water has no taste; it is just hydrogen and oxygen.

Also, proper coolant change intervals is recommended to keep the corrosion inhibiting properties.

 

sounds like good advise, ever heard of the 3 ltr having brown water all the time regardless to what you do? It never goes away

 

Oh, question, anyone know how to check the electric fan? With-out having to stand and let it heat-up? Does it have a fuse? Can you pull wires to see if they have juice? Thoughts?

 

this is embarrassing! Ford found that my water bottle was cracked and system low of fluid! Man I didn't see that...