Towing Temps

[HEYBOSS]

Please bear with Me a little as I'm new here and still learning how to navigate. 2001 3500 4X4 auto 4. 10 rear 11,300 miles on it, all stock. Just towed 30' fifth wheel on a 3000 mile round trip to Fl. and back to RI, weighed in at scale truck and fifth wheel 18,600 , just 400 lbs short of my truck's max cap.

Now my question. At 2100 rpm I was doing 68 on flat ground, my temp gauge was just passed the center white line above the 190 deg. mark. The truck still had power, but if pushed it to 70 the gauge would start to cover the "0" mark of the 190. That concerned me a bit, I figured it was probably reading around 210.

Now as I start to hit the state of Ct. and encountered some hills, I would have to do 75 down hill to do 60-50 top of hill. Has I had a "ferd" on my tail on one hill and slowed down to 50, locked out the OD and floored it. The engine screamed and she went, but my temp. quickly got half way between the white center 190 line and the last white line. I only did this once and feel as if I'm running a little to hot. Is this a normal condition when towing. Heck I don't want to be stuck at 68mph when I know I could push it. Sorry for the long post. Definitely will be adding some gauges for starters.

 

[DonBaggett]

When mine gets just past the half-way mark, I can hear the auxillary fan kick on, and it doesn't move past there. I think if I were you, I would stick in a new thermostat. One of the cheapest things you can do, and it sounds to me like yours isn't doing all it's supposed to. These trucks have a great cooling system on them (Supposed to burn the Ferds up who get behind them!)

Don

 

[JJW_ND]

Normal!

The stat is just fully open at 190 - 200. I would worry if your are pushing the 230 mark.



Temps should rise when working a diesel unlike a gasser.



Runner hard. It will treat you better after a few good trips!



jjw

 

[Dieselnerd]

It's not normal, these trucks have great cooling systems. Mine only ran over the center of the gauge one time while towing a 14K fifth wheel uphill in Nevada on a hot day. It was a bad thermostat. What happened on mine and I have heard it is common, the rubber ring molded around the body of the thermostat came partially loose and actually impeded the coolant flow even though the thermostat was wide open. It never got up to the danger zone but I was worried for a while. They are cheap and very easy to change. I always carry an extra with me now.

 

[HEYBOSS]

I did hear the aux fan kick in once in a while. Cool Thing. I don't think the thermo is bad. With out load temp goes up to 190 and then I see it come right down below 190 and stay there. Keep in mind the fifth wheel is very tall and has a big frontal area, also very heavy, over 9000lbs empty. Thanks so much for the reply, I think I might want to bomb this thing a bit. I'm still new at and want to do some research, this is a great site.

 

[HEYBOSS]

Sorry guys, I take that back on the thermostat. It is possible for a thermo to show ok when not pulling a load, I've seen this before in automobiles. I will definitely take up on the advice and change the thermostat this week end. It is cheap insurance and piece of mind. It will be a while before I pull my fifth wheel again, but a least I will have a visual look at that therm. I will report back, thanks so much for the advice, Fred.

 

[chuck3]

temp.

I think thats pretty much normal, heck mine does that running empty around in this 100+ temps

 

[RHARVEY]

What is this auxillary fan? I thought that after you reach 35-40 the fan has no effect on the temp. I have also changed the stat and have not pulled in the hot weather yet to see what it will do. Make sure that you get the latest stat that you can so that you wont have the cycling temp guage problem.



Rick

 

[jstyer]

Towing Temps.

Good Luck and Welcome aboard. You wil find that this is the best $35 you ever spent on your truck, joining the TDR.

If you are considering "Bombing", the first thing I would do, if you are going to tow a lot, is invest in a Pyrometer to monitor your exhaust gas temperature. I tow a 35' 5'er but it doesn't have a high frontal area to create excessive drag, so I have never seen my temps go as high as yours.

 

[KOUNTERSC]

Where is the aux. fan located. I looked for it. All I see is one big fan.

 

[DonBaggett]

I guess it's not an auxillary fan, but the one fan that kicks on good and loud when the temp hits around 200.

Don

 

[HEYBOSS]

Yes that should be rephrased. It is not and aux. fan. I believe it's the fan clutch that kicks in causing the fan to spin at a much higher speed, cooling off the radiator.

 

[illflem]

I agree with what JJW-ND said, run it hard it will mellow out. I think until you have some miles on the truck you will be wasteing your time to mess with the t-stat.

 

[Shooter]

T stats are about $14 from Cummins, I have had 4 in 35k mi. When and if you get a good one it will maintain 190 in dead of winter and 190 towing 16k up a 6% in 120* ambient. I had one but it started leaking so I replaced it, a couple would hit 220 on the high side and 130 on the low side. My present one will hit 200 on the high side and 160 on the low side, The 160 will occur in 100* towing level.

 

[DonBaggett]

Thermostat = real cheap

Engine = real expensive

For Me = Wouldn't be a hard decision at all.

 

[HEYBOSS]

reporting back

Well, I replaced the thermostat a couple days ago. Didn't see any thing wrong with the old one, seal was not damaged and in place. Just came back from a road test with the 5er and I really don't see any difference with new thermostat. Temp. runs 190 and just below it at 50-55 mph, take her up to 70 and temp just goes over the 190 mark in OD. OD off and floor it, temp climbs more but still in the normal range. I want to put on some gauges and go from there, for now I'll just take it easy.

Thanks to every one for their effort and comments.

Sincerely, Fred.