I started having an overheating problem about a week ago on my 02 4.7. Checked coolant and it was just a little low and i noticed that the e-fan wasnt coming on when i turned the ac on. I went on and unplugged the ect and the fan kicked right on.

My temp gauge does move up and i got the check gauges light twice already while sitting in traffic. Could it be the relay or the ect? where should i start

 

What do you mean by ect?

 

 

Rather than start a new thread I figured I could piggyback on this gentleman's post.

I have a similar issue it sounds like - and I've done a ton of searching here and other places but I guess I can't really figure out what the best way to diagnose an overheating issue is.

Our '02 4.7l started overheating 3 weeks ago while we were climbing up a mountain to pick some huckleberries. We came home, I replaced the thermostat with a 195 degree, and drained/replaced the coolant with 50/50. Hydrometer shows -25 (4 ***** floating, one halfway).

Yesterday we climbed up a rather hilly portion of town, parked for about an hour, then went down the hills. Once we got to the bottom we drove back up a incline on a main drag in town and it started overheating again - the idiot light came on to "check gauges" and we were almost touching the red H. We blasted the heat and we got back down to about 1/2 way between middle and "H." On the freeway it cooled off even more, but as soon as we got off the freeway, idiot light came back on and we were in danger zone.

What's the best way to diagnose this? I don't want to just throw parts at it. We have no coolant leaks. When I turn on the AC the Efan is spinning. Any tips on how to narrow down what the problem could be would be awesome! Thanks guys/gals!

Edit: Oh and... no sweet smelling exhaust or smoke - I don't think I am leaking/bad head gasket but I am no expert - just a guy who doesn't have money for a shop

 

Bad viscous fan clutch maybe.