2011 4500 Overheating in 4th

[PLefever]

Looking for ideas, pulled a pretty good load yesterday through the Flint Hills of Kansas, the truck will pull hard in 6th (automatic) with all systems stable, transmission temp, engine temp ok. slip into 5th and engine temps start to crawl up, after losing speed to about 50mph slip into 4th (direct) engine turning 2450 or so, transmission temp still steady, engine temps rise rapidly 20 degrees in just a few seconds, having to back out when they pass 235, kick it back into 5th temps come down some, back into 6th, temps drop to normal. Engine fan is working fine. If engine speed is up, thus more water flow, air flow, why does putting it in overdrive reduce temps when the transmission temp is stable? EGR? exhaust backpressure?



thanks perry

 

[HBarlow]

Perry,

I've never seen any overheating in mine and it now has about 105k on the odometer. I don't think the temp gauge has ever moved beyond an estimated 215* - 220*.

I don't remember exactly but I'm thinking the red band on the temp gauge is at 260*. If your engine is not getting to the red band it is not overheating and probably no need to worry about it.

What is your gross combined weight and what is the slope of the grade you were pulling? Did you perhaps have a tail wind which reduced air flow through the radiator?

 

[PLefever]

Harvey, in 6th mine will stay 215 to 217. If its a 7lb pressure cap boil would be around 260 or so. Conditions were tough, scaled at 38,700 (don't tell the gcwr police. . lol) Aerodynamics were horrible, load was 12' tall, 15mph head wind, 4 to 5% grade oh and it was 105



The odd part and alarming was how fast the temp would climb, I'm not talking over several minutes of a long pull, I'm talking seconds. I don't have alot of faith in the regular guage so I was watching the scroll down info guage and to see if temp on transmission was changing.

It would shoot past 235 so fast I have no doubt in my mind that if I had not lifted and kicked it up a gear that I could melt it down at will.



The only thing that makes sense is backpressure or egt feeding through the egr. I could pull the solenoid on the egr and go and run it and see what happens, it would set a code but oh well.



Why would it get worse in lower gears? except related to engine speed. The other thing is that if I sped up to 70mph and then slid through the gears as I lost speed, it wouldn't heat as fast.



By the time I got home it was 88 degrees and still doing it. Called svc manager, he's checking into it,

 

[PLefever]

Just a thought, if I speed up then airflow increases through the coolers and thus temp exchange, if the fan is running full boogie and I'm going too slow for the air volume the fan creates could it be cavitating (not sure if thats the right term) and not moving air subsequently heating? maybe electric fan set as a pusher?

 

[HBarlow]

Perry,

I had to go out to run an errand and drove my truck this afternoon. I remembered your thread and looked at my temp gauge.

My memory was incorrect. Center mark is 200* and red line is 245*. I don't think mine has ever heated beyond about 210*.

I've never hauled a combined weight anywhere near 38,700 lbs. That weight and bad aerodynamics combined with high ambient temp would make a big difference.

Did you hear your clutch controlled cooling fan kick on and roar? Mine makes a roar that could never be overlooked.

I can't say why it ran cooler in 6th/2nd OD. That goes against what I would normally expect.

 

[CUMMINZ]

My experience with 3 different CTDs: When I had a 2004. 5 SRW with TST on about 60HP setting and a trip out west thru Kansas- and driving out the interstate with only a small 29 footer fifth wheel. I have often compaired the long drawn out pulls across Kansas as some of the toughest pulls there are. While pulling in the mtns. of NC I can get into a lower gear and chug along with rpms on the high side and never see any overheating. But across Kansas with some grades being 10-12 miles long I saw some of the hottest temps. Your engine is in a hard high gear pull most of the time. The DPF/cat filters are greatly to blame for restrictive heat flows. You are going to have to keep your rpms up and speed down. Your total weight is not helping you.

 

[PLefever]

Yeah, I didn't help myself much, picked a super hot day then overloaded to boot, but having to travel 400 miles to get feed I didn't want to leave any space open. . I have pulled combined that weight often, however it is usually steel products without the massive wind profile, and frankly I usually drive faster. I had separated a cord on one tire and the spare wasn't too healthy either, so tried to keep speed down so I wouldn't pop anymore tires.



I agree, some of the hills in the flint hills can run for miles and miles, and they pull really hard, you get wind moving around you based on the hill formations.



My usual load is about 10k less and the 4500 doesn't flinch, even with these little issues

it still outpulled the 98 in my signature which has made the same trip same load before, and never again.



I saw where H&S now has a delete for the C&C urea/dpf/etc, I know when I took the dpf off my ford 450 the engine fan never ran again, so much cooler...



Harvey, yes the fan kicks on and is just howling the whole time

 

[NIsaacs]

Ground speed plays a big part in cooling when all conditions are against the system, making it marginal even at 60 or 70 mph with the load, ambient heat and even the wind. Once you drop to 50 or under they can't keep up. I have noticed this a lot over the years as a cooling system starts loosing it's efficiency for whatever reason. Another identical truck and load might have done the same as yours did on this day and on the road you were on.



Nick

 

[Hoefler]

Look at the exhaust system, you may be plugging up. As the RPM increases, a restriction is more noticeable.

 

[KLauber]

Usually being way over GVW causes all sorts of issues. Bet the Cummins engineers would frown over this thread. My 2 cents since I drive a manual trans and never go over 26K GVW.

Ken

 

[TulsaOkie]

Those Kansas hills got to me last week. truck temps were around 214, and transmission around 184, 29k was no problem... . sure am happy with this 2011...

 

[PLefever]

Klauber, you are not doubt correct, there have been great debates on tdr (been involved in a couple) of how the manufacturers determine GCWR and why it appears random. I believe Harvey pointed out mechanical issues in one of those threads, well kids, think I found a weak link. . ha, that being said, I would like to figure out the no heating in 6th but quick heating in 4th, that just goes against what I've ever known or thought I've known. .

Just a side bar, the 4500 chassis is superb, it handled the excessive weight unbelievably well, brakes, exhaust brake, chassis, couldn't be happier, and in this heat I'll cut about 4k off my load and all will be peachy

 

[HBarlow]

Usually being way over GVW causes all sorts of issues. Bet the Cummins engineers would frown over this thread. My 2 cents since I drive a manual trans and never go over 26K GVW.

Ken

Why would Cummins engineers care?

The same engine is sold for use in MDT Furd F-650/F-750 and other truck chassis rated for much higher gross weights.

 

[KLauber]

Why would Cummins engineers care?



The same engine is sold for use in MDT Furd F-650/F-750 and other truck chassis rated for much higher gross weights.

Maybe the highway patrol would frown, eh? Yer right, Harvey, the engine is used in much higher GVW configs. A friend has a 38 foot 2010 motor home with the 6. 7L rated at 340 HP in it. I rented a Ryder straight truck to haul some drums. The Freightliner was powered by the 6. 7L and a 6 speed auto and handled the 38K gross with nary a whimper. Good thing I went around the scales too!



Ken

 

[HBarlow]

Nope, HP would not be concerned either as long as the OP was licensed (CDL A), plated (weight taxes paid), and not overloading any axle.

 

[AH64ID]

If my memory serves the 6. 7's use a 200° thermostat that don't go fully open until nearly 220°, 15° above full open is a possibility and can happen easily but generally in higher gears.

How old is the thermostat? I wonder if it's not going full open and with the added rpm the back pressure on the system is wreaking havoc on the abilities to cool.

 

[PLefever]

Believe it or not, I was under my combined GVWR, and scaled combined and axle, even tires were with in check, so the constables didn't have anything to complain about. Truck and trailer empty weigh right at 18,800. Scale house doesn't care about GCWR. Brakes on my trailer are good enough to pass any brake jerk down test. I know it sounds like alot of weight but here in oil field country there are 100's of medium duty's pulling these kind of loads, everything from hotshots to oilfield roustabouts so what seems normal to me, may seem abbynormal in other parts of the country, but then again, I've been told you can't "go" insane, you have to be "driven"

 

[CUMMINZ]

What you should do with your 4500 is to take it into your dealer and have him download and print out the percentages of load that you have run the truck. It will let you know how much strain you are placing on the engine.

 

[PLefever]

truck has about 18k on it, doesn't mean the thermostat is ok, but should be

 

[PLefever]

Cumminz, plan on doing that monday, should be about 100%. . lol