Cummins ISB 6.7 360 hspwr normal engine temp range

I drive a bus for our local school system,All of our newer buses run higher temp (205-210 range)than we thought was normal. after speaking with the International techs we were told not to worry about temps until they got above 220.
In years past I owned a couple of mack tandems coal trucks and if they got around 200 we stopped or downshifted so temp would drop.
The newer engines are designed to run hotter and as was mentioned it is due to getting a cleaner burn and cleaner emissions
FWIW I personally would contact Cummins and speak to a Tech and get a real expert opinion .that if you have a problem you can catch it before you destroy a good engine,or if its normal you can have peace of mind when operating it.

Assuming the gauges are actually accurate the new engines as quoted run hotter to burn off the bad stuff and the DPF's or DEF systems are there to burn off carbon residue. These systems also cause heat retention however the coolant temperature is the restriction in running diesel engines hotter for better efficiency and power. Adding 6000 lbs will slow the vehicle on a grade slightly but only affects the cooling system in cycling times. Allison transmissions should be run in "performance mode" on long hills to assist cooling by raising shift points which as stated increases coolant flow and maintains higher air movement via the fan through the radiator. If you are still running to hot manually backshift a gear and run the engine on the governor which decreases the load on the engine with max cooling.

et2 wrote:

dan-nickie wrote:
In the last couple week mine has been running 198-200 on the flats in above 90 weather.
Same engine.
Any incline and it would heat up a little until I got over the hill.

That sure looks like a Ford engine? :W
Can't compare the two.

You been looking at my profile? :)
I traded that one off on a new DP.
Just have not updated the profile yet.

dubdub07 wrote:
All I am saying is that a Ram truck has no alarm and the engine often ran up to 230 without issue. Tranny once climbed over 250 outside Telluride.

Which factory are you referring? Chassis or Cummins?

Fan sounded like it always did.

I don't think that 200-205 is hot at all. My 8.3 will run about 210-220 with tranny temps staying around 200.

It wasn't the factory, my bad. It was the Cummins information line supplied by Frieghtliner. So it was Cummins.

All I am saying is that a Ram truck has no alarm and the engine often ran up to 230 without issue. Tranny once climbed over 250 outside Telluride.

Which factory are you referring? Chassis or Cummins?

Fan sounded like it always did.

I don't think that 200-205 is hot at all. My 8.3 will run about 210-220 with tranny temps staying around 200.

230 degrees and no alarm? Cummins told me it came on at 220. I watched the trans temp as well. It ran 8 -10 degrees cooler but at hill pulls it matched the engine at times. In the Allison manual it says 250 and the trans fluid must be changed.

I'm not understanding why the factory says it alarms at 220 and must be attended to. You're saying you exceed that by 10 degrees and it's not a problem? Is this with the fan roaring as well? Because mine did hit 210 maybe 211 and the fan quickly settled it down to under 200 . I'm just not comfortable it running at 205 most the time on a 85 degree day - no traffic - running 60 mph on the freeway.

I guess I just need to go faster :?

I have owned 3 of the Cummins 6.7s in Ram trucks and I can tell you that all of them pulling heavy (20K combined weight) the temp would routinely run into the 230 range without a light or troubles. You see where I live, so the towing I did was not flat-land straight ahead towing either.....

WW

et2 wrote:

Sundance07 wrote:
The new 6.7's run hotter for a reason. It is due to the EPA mandated emissions equipment. Hotter = Cleaner

But isn't that what the after burner and DEF is for? That isn't part of the cooling system to my knowledge. I might be blowing smoke, but it concerns me I'm significantly under weight 4,000 lbs on GVWR and 6,000 on GCWR, and the engine temps are were they are. I,m concerned if I had an additional 10,000 on the engine to pull, and still within its capacity according to the manufacture, I'm going to see it way higher.

To a point, the higher temp thermostats that are now in the 6.7 increase the engine temps which effect the whole combustion process. They want a higher engine temp for a more efficient burn, reducing soot which ultimately gets to your exhaust and emissions equipment.

Sundance07 wrote:
The new 6.7's run hotter for a reason. It is due to the EPA mandated emissions equipment. Hotter = Cleaner

But isn't that what the after burner and DEF is for? That isn't part of the cooling system to my knowledge. I might be blowing smoke, but it concerns me I'm significantly under weight 4,000 lbs on GVWR and 6,000 on GCWR, and the engine temps are were they are. I,m concerned if I had an additional 10,000 on the engine to pull, and still within its capacity according to the manufacture, I'm going to see it way higher.

dan-nickie wrote:
In the last couple week mine has been running 198-200 on the flats in above 90 weather.
Same engine.
Any incline and it would heat up a little until I got over the hill.

That sure looks like a Ford engine? :W
Can't compare the two.