2005 dakota 4.7L V8 runs hot in hot weather

[Connors_Daddy08]

I know I'm a bit late to the party, however I just had this same thing happen to me.

I completely rebuilt my 4.7 last December, which included a brand spanking new fan clutch. All has been well. That is, up until last weekend when we finally broke 85° and did it with a bang and hit 98° as our high (Hickory NC). Keep in mind, this happened with the AC on as well.

I noticed that idle tell temperature gauge would periodically hide the mid temp mark and sometimes go just above. This is very abnormal for my truck, as it has always run below the mid mark. I also have a digital scangauge (obd2 direct hookup) and I can set it to show any PID that the truck offers. I have mine set to voltage, water temp, instant mpg and avg mpg (because I like it better than the mpg reader that came stock).

Normal driving never usually goes above 204°F and at idle, never above 209°F

Well.... to cut this short, while driving this past weekend, I hit 222°F at idle, and would fluctuate between. 211 and 220 while moving. If I parked, I could watch the temp rise to 222 again, and if I brought the RPMs up to 1500, you would then hear the fan kick in, and thus the temp would drop to 204.

So, again, I set out to drive... and the same thing would happen. .... but I noticed, I couldn't hear my fan spooling up even when reading 218 or more.... I stopped.... opened the hood and tried to slow the fan by hand.... and no luck....

The next day, the same scenario. So I called up the parts place I got the fan clutch from when I rebuilt the engine and found it has a lifetime warranty. I swapped out fan clutches, and haven't gone over 204° since.

[Greenbow]

I have a 2005 with 365,000 on 4.7, second owner, I got it with only 75,000, it never heated up but the last few years it has. new fan clutch, water pump, thermostat, rad flush, runs hot with AC on all way up to top, turn on heat and it comes down, lost on why.

[philipat]

how do the fins look on the radiator? If you have too much rot in the fins, you're not cooling the engine.

I had a similar problem a few years back on my Neon. It was fixed after replacing the radiator. If you have that many miles, you're probably overdue for a new radiator.