strange phenomenom
 

Greetings,
A strange thing happened over the weekend we were pulling a camp trailer from Idaho Falls ID to cherry hill in Utah, a distance of about 200 miles. Trailer is about 23 feet long, weighs around 5000 lbs. Ambient temperature was around 100 - 105 degrees. We were pulling just fine with the Bullydog pmt in tow setting cruising at 80 mph. the road was fairly level, a few gentle ups and downs, egts were 850 -950 pre turbo, coolant was 195. about halfway through the journey and just before a 4 1/2% grade, temperatures started climbing to about
201 and 1050 (coolant / pyro) then we started climbing the grade. trying to maintain a speed 0f 75, temps rose and defueled the coolant at 210. then the pyro defueled at 1250 so i backed off the throttle and limped up the grade at around 60 mph. once we crested the grade she cooled down and the rest of the trip went smooth. Coming back home it was a different story. As we approached the same area going the opposite direction, as we started to climb temperatures skyrocketed to 214 and 1300, boost was pegged at 30 it Defueled and limped up at 55 mph (this is a gentler grade by the way). any attempt to go faster than 60 was met instantly with defueling. so the truck struggled up at 55 which put temperatures at 208, 1200, and 30 psi boost. it was almost like the engine was fatigued. if i let off the throttle, we slowed down. if i gave more throttle, we slowed down. it was extremely frustrating. once we crested the grade and coasted down the other side it cooled back down. then a stranger thing happened. once on level road it started heating up again. we were crusing at 75 mph and could go no faster if i tried more throttle, the vehicle wouldnt go faster, if anything it slowed down. we were cruising as 75 mph and boost was 26-27 psi This whole time, it has seemed like i wasn't getting any help from my turbo. like the engine was having to do all the work.so there we were trying to keep with the speed limit on level road, 5000 lbs in tow, running 210 coolant, 1200 egt and 27 psi. it also said engine load was over 65 percent. The situation wasnt improving so i pulled to a rest stop, let it idle for about 10 min, then shut it off and let it cool down for around 30 min.
when we continued back on the road it was better, same conditions but at temps of 197, 1000, and 19 psi. Around 45 min later the strangest thing happened . all of a sudden the ac suddenly turned super cold, and all my tepmeratures dropped like a rock and stayed at 195 850 and 16 psi the rest of the way home. when i got home i popped the hood and the intercooler tank on the turbo side was hotter than hell.
What is frustrating is this is not a heavy trailer. granted it was hot outside, but with the truck in my sig i don't think it should have struggled so much. i need to remedy the problem, but don['t know where to turn. any thoughts would be greatly appreciated.
Thanks in advance
Travis

Maybe your fan clutch isn't working right or at all. Sounds like all of a sudden your fan turned on.

The a/c thing on top of it all is what makes me think this. The fan is the only thing tying it all together.

yes, the hot side of the intercooler will be so hot you cant touch if your pulling hard. it does sound like the engine fan was not working then all of a sudden started working.

I'd be thinking fan "clutch."

I had a very similar experience with my '05 2500 5.9L TD HO stock.

I was pulling a motorcycle trailer, guessing less than 3000 lbs., going up a steep grade, ambient temps close to 100 deg's. Coolant temp rose to to approx. 220. Ran like no turbo was helping, tranny would shift earlier than normal. Once on a the hwy., not climbing any longer, the coolant temp would drop back to norm and ac would cool. I do mostly hwy driving. However, the coolant temp would rise when I am in stop and go traffic with higher ambient temps.

I changed my water pump, 3 times before I found one that would not squeal. With the two squealing pumps I experience the same problem as above. Now running the 3rd water pump with "gold" antifreeze, coolant temp seems to hold around normal but the ambient temps are only in the high 70's to mid 80's. But when sitting at a lengthy light the ac still blows warm/hot air.

I would like to know if you end up replacing the fan clutch and if it did the trick.

Both cases sounds like the fax clutch is out


Back from the forum grave

I have read that OE is the way to go when replacing it. Is there an after market brand out there you would suggest?

I would stay oem.


Ready to be back in a truck

Thanks for the replies. I think it is the fan clutch that is the problem. I don't think
I have ever heard the fan turn on. But I would hate to spend money on a new clutch if the problem is only a relay or a sensor or something. So I've checked the no 17 fuse, the fan has no play in it, the fan turns by hand and has resistance to it. Theres no noise when you turn it. the harness is tight, what other tests can I do to identify the problem?
Thanks