Got a P0118 today after some work on the cooling system. I've been trying to determine why my truck overheats only while pulling my trailer. I dropped the t-stat in a pot of boiling water, along with a new one (both 195º) and they fully opened. I snapped off a bolt on the t-stat housing, so my machinist drilled out the stud and tapped the hole for 3/8". I also checked on the flow of the water pump, which was strong. I reinstalled everything and worked to purge the system of air. The CE light came one, and my code reader pulled a P0118 - High Temp Sensor Reading. I am positive I got the two small sensors on the intake reinstalled in the proper locations (one is black, the other is grey). I cleared the code, and practiced towing mytrailer around the yard and the temp didn't get above 200º. Any ideas how to handle this code?

The machinist and I decided that the clutch fan is going out. I'm going to replace it with a flex fan.

 

A rhetorical question? Personally, I think that you and your machinist have it nailed. This based on the fact that you recently rebuilt, and the assumption that you haven't been using muddy water for coolant.

 

if the fan clutch is bad why not jus replace that ? flex fan is not gonna do crap , you be in the same boat but with a flex fan..lol

 

I have held a Flex-a-lite fanoff a 440 and it weighed almost nothing. I have electrics now, but, after hearing the motor bog a little after the second fan cuts on, have often thought about whether a Flex-a-lite mechanical fan wouldn't be better from a mileage/power standpoint. From a pcm harmony standpoint though, I think it might be bad in the colder months. The Flexa... fan would have the tstat opening and closing and the ect reading would be shifting from several degrees above the tstatsetting to way below it's setting by the time it opened. Kind ofin an either on off manner. I don't know how the adaptives would react to this.

Either way, I don't think you'll get that code anymore if you follow your (and your machinists) instincts.

 

Thanks for keeping score on me, Mopower. I don't expect mileage gains or anything like that with a Flexfan. I personally abhor clutch fans, plus I am running a 3-core brass radiator vice a 1-core aluminum stock. I still don't understand why I am getting a P0118.

 

Like I said, I think you nailed it.When the goo in the clutch goes, so does the fans ability to cool the engine. Way back when before climate control and electric seats, they used to call it a fan belt. Use a straight fan and see what happens. Just please let us know.

Man, your rebuild is famous. I'm not keeping score, and it was the way you went about it and the way you wrote it up that put me under the assumption that you're smarter than to use muddy water for coolant. I, as well,hate a viscous clutch fan.

 

Thanks for the kind words. I hate it when people half-*** anything, especially under the hood of a vehicle. That's why I was so particular about my rebuild and how I went about it.

I will definitely keep you posted on the fan situation. Keep your eyes on this thread.

 

OK, went to the machinist today. He determined that the clutch fan is shot. I ran the truck, killed it, and right away he said the clutch to the fan is bad. It wiggles and when the engine shuts off the fan keeps spinning. O'Reilly Auto Parts wanted a king's ranson for a new fan clutch, so I ordered a new one along with some badly needed shocks from Rock Auto (http://www.rockauto.com). My parts should be in by Wednesday and I'll be able to report back by this weekend.

 

Is it just four bolts that hold it to the fan? The ones I see online have a large nut on them. Does the nut come off and then the four bolts hold it on or something else?

 

right behind the clutch is the 4 bolts that the fan mounts to , the clutch it self has the big nut ..I got my fan clutch at advance auto parts for $ 63.00 Severe Duty .