this can't be normal!.......can it?

[pipeguy]

Should the cooling fan be spooling up under non-towing highway conditions?

Back in mid-June I drove my '04 (4wd, crew-cab, 8'box) 500 miles from home down to S. Carolina. It was a 4AM - 1PM drive which included a couple of pit-stops. Only one passenger on-board and no freight or towing. We stayed a night and the next day and headed back towards home around 5PM.
After a couple of hours I started running the interstate pretty hard hoping to cut an hour off the trip. The windows were up and the A/C on to quiet the cab and it was then fan started briefly spooling up and down when I'd pass already fast moving vehicles. As the phenomenon is pretty loud and it'd never before happened it kinda' set me back in the seat and after checking the factory gauges for signs of trouble (none) I began nursing it at 75MPH or lower (75 mph = just about 2100). The fan activity ceased and I hadn't heard it again 'til this past weekend when..........
I ran the same trip with 2 passengers and a bed full of household cargo. Again, I left at 4 AM but wasn't 90 minutes down the road when the fan began cycling for longer and longer periods at engine speeds above 2000 rpm. Again, no sign of trouble on the factory gauges. I stopped and topped less than a quart of coolant. I noticed then there was no pressure on the coolant cap when it was removed hot. I didn't hear from the fan for another couple of hours when it cycled briefly once or twice. By the time I got all the way down the road (8 hour drive time) the fan wanted to run almost constantly above engine speeds of 1750 rpm (65 mph). Between local stops and in-town driving the truck had maybe 3 or 4 hours intermittent down time before I headed back home around 6PM with 1 passenger and an empty bed. The fan immediately started cycling constantly for brief periods - maybe 40% off 60% on at engine speeds over 1750 rpm. I ran under 1750 rpm ( 55-65 mph) all the way home through several extended stops - this time over something like 14 hours, with only a couple of brief fan cycles. A couple of run ups to almost 2000 RPM resulted in the fan cycling on.
I stuck an electronic thermometer in the coolant resovoir within 90 seconds of hitting the driveway (again no pressure on the coolant cap) and watched it track from 213 to 195 in less than a minute at engine idle.
Thoughts on where the problem might lie or how to pin it down? I gotta' go back down the road in a couple of weeks.

[TurboSevenThree]

213 sure doesn't sound normal i give ya that. It sounds like your fan is working properly if it's getting that hot. No strange noises like a shot waterpump or leaks anywhere?

[pipeguy]

Originally Posted by TurboSevenThree

213 sure doesn't sound normal...no strange noises like a shot waterpump or leaks anywhere?

no noises or apparent leaks. since new it's seemed to need a 1/2 gal of coolant every coupla' months and has always continually developed white grit around the tank cap/spout.
what's the normal operating range for water temps? I'm thinking I'll start with getting some real gauges

[chuckles]

you are puking coolant, if you have do add, and there is residue around the bottle.

EGR Cooler is most like toast, along with oil Cooler, and head gaskets.. are you still under warranty?? if so I'd take it in and if the hG's are done, have them stud the engine with ARP head studs.. This will keep this problem from occurring again.