Engine Temperature on Grades

[PWelsh]

My son just moved to hill country. He reports that his water temp goes to the extreem high temp but stays out of the red when towing his 5th wheel up steep grades. He stopped and put the transmission in nutral, the engine idles at high speed until the temp returns to the normal range. Is this normal or has he got a cooling problem? Thanks. O'yes, he has a 2003 CTD, auto, 4. 11.

 

[klenger]

The temp in mine barely climbs in the hills.

 

[Bertram65]

Guess it depends on the size of the load and the hill, I did some climbs too about 5000' towing 10k lbs at 2500rpm in 3rd several weeks ago and the temp needle was just to the right of the 200 mark, normally it is either right on the 200 mark or just below it. Sounds like it could be a problem unless it is a huge load and a huge hill.

 

[GerryDrake]

Fan

Does he definitely know it when the fan kicks in ?... Although mine is a 6 speed, when the fan kicks in I can definitely hear it, and watch the temperature come back down. He might not be having the fan kick in, which would certainly explain the high temp problems...

 

[Bill Stockard]

I don't tow a 5th wheel, but haul a large heavy slide-in camper at my truck's max GVWR. I notice a coolant temperature increase on long steep grades at the higher elevations in the mountains of CO, WY, and MT. The fan cycles off and on to control the coolant temperature. I manually shift the automatic transmission down to lower gears to keep the RPM above 2200 when climbing these grades which keeps the torque converter locked even in 2nd gear.



Your son could try shifting the transmission manually to keep the RPM higher which increases the flow of coolant and fan speed. Also at higher RPM, there is less torque converter slip(oil shear) which creates extreme heating of the transmission fluid. If he manually shifts to 2nd gear and keeps the engine speed above approximately 1800-1900 RPM, the torque converter will lock up preventing torque converter slip. Cummins gave us a wide RPM range in the 24-valve HPCR engines to work these trucks, don't be afraid to use it.



Bill

 

[jackcaptjr]

At what point on the temp gauge do you see the fan kick in? I tow 12K-14K and see the gauge climb about 2 needle widths above 200 but the fan has not kicked in at that point... ... ... . never does except at slow idle speeds around town.

 

[Bill Stockard]

According to my '03 FSM, a properly functioning thermostat begins opening between 186 and 193 degrees and is fully open at 207 degrees. I think fan will probably engage somewhere between 207 and 210 degrees since there is no point in the fan running until the thermostat is fully open. I have no idea (and don't remember) at what the temperature the fan will cycle off, but it probably will remain on until the temperature sensor in the cylinder head detects the coolant temperature down to about 195-200 degrees.



Bill

 

[GShail]

Check that fan clutch

 

[jwduke]

I have yet to see mine climb over 200 pulling my 5er.

 

[Diesel Nut]

Mine goes to about 205-210 pulling 13K over 6. 5% grades @65 about 90* ambient, and the only time the fan kicks on is if the A/C is on. Pop er outa OD, shut off the A/C and put the hammer down. RPM's are key. Keep her around 2500-2700. Above that the engine has a high amount of drive pressure and egts can rise, and with 4. 10's that truck should have no problems. I have 3. 73's and 35's and no temp problems. Good luck!

 

[macdaddy]

Sherwin Grade No of Bishop Ca, 7% 11 miles 105 degree's outside 18K GCW with a bug screen I know I know 5th gear 60 MPH @2700 rpm and A/C on. It only got a #%& hair past 200. Damn remarkable vehicle.



The 05's anyway will start the fan as soon as the A/C is turned on, but I really don't hear it as much as the 99. However if I slow after a hard pull and have to row through all six she'll really roar until about 45 MPH and 5th.



Mac

 

[GShail]

Fan Clutch

 

[GShail]

PWelsh is having a problem similar to mine,



HELP!!!!!!!

 

[fyrescott]

That's normal for an auto transmission to reach 210. My 05 can reach that pretty quick while towing up a grade. My 02 pulling the same trailer on a 110 degree day up a steep grade will only hit 200 max. Auto transmission+Towing=Heat.

 

[bighornram]

I'm with a 6 speed but pulling 12K+ to 12k feet elevation and my temp guage stays right around 200*. I notice EGT's are higher than my 02' did but keeping the RPM's around 2000 will bring the EGT's down in a hurry. Happy pullin'.

 

[CLAYTON]

That's normal for an auto transmission to reach 210. My 05 can reach that pretty quick while towing up a grade. My 02 pulling the same trailer on a 110 degree day up a steep grade will only hit 200 max. Auto transmission+Towing=Heat.

I think their talking about engine temp and not transmission temps.



Mine engine temp will climb up into the 225-230 temps sometimes. I'll have to get my fan clutch looked at.

 

[jelag]

My 04 has 140K miles. . and pulls between 15K and 22K lb trailer 95% of the time... .



On a flat and level road the temp needle runs between the 2 and the first 0... . on a slight grade it centers on the first 0 and going up a steep grade in 3rd or 4th it will go to the center or just off center to the right of the second 0..... I pulled the Siskiyous and the grapevine yesterday..... at 95* and didn't have a problem with the AC running wild. . and across the desert to Phoenix at 110* with the same results...



I never get close to another truck..... always leave 100 to 150 ft when I can... . getting behind a truck grinding up a hill blocks the air flow and the temp goes up fast... if he has to slow and I can't pass I hold the gap and slow down... .



Pulling this weight and these grades the fan turns on and might run the full grade... . Hope this helps... .

 

[BIG BOB]

Check that fan clutch

Mine just went out a couple of weeks ago. I have also heard of others that the clutch fan has gone out. Check it!

 

[CLAYTON]

Whats the best way to check the fan clutch and is it an easy fix?