Just got the radiator rodded out and installed flexalite fans. I live in northern ca and on a recent trip i was notice that my coolant temps while towing up a 6% grade for 5 miles with 6000 pounds in tow was up at the upper limit of normal and still climbing at the top of the grade 4500' boost:25-30 egts:1050-1100 5th gear 60 mph.

Stopped in the next town and notice that I had puked coolant out the overflow (found out later about one gallon or so)

Has always seemed to run warm to me while towing

I have a cycling thermostat

Couple of questions now

Is the fans?

Would swapping the HX35 for a super b help I have one on my other pickup.

should i have grabbed a gear had plenty of power but 1800rpm instead of 2200 in fourth?

Any help would be great can't figure this one out.

 

it shouldnt overheat like that at all.. maybe ur thermostats stuck closed, or your fans arent working there best.. id check everything that had to do with the cooling system first

 

Did you remove the stock fan?
I feel that any speed above 45 the fan is of little or no help.
Is the pyro pre-turbo or post?
I ask because it is very hot pre-turbo if the pyro is post-turbo. This heat is the issue. It is cooking the head.
did you flush the cooling system.?

 

Has the water pump ever been changed. Water temp is one of the big reasons I ditched my 6.5 in my dually, as far as I know every cummins I have ever rode in or drove while towing didn't get hot if everything was working right

 

besides the obvious (clean rad. t stat, clutch fan ) I would check for exhaust getting in the cooling system .the cooling system should be good for close to 400 HP and 6000 lbs is no load I tow 17,000 and never have a over heat issue

 

I would say the electrics are not keeping up with the demand. The stock fan will pull 8,800 cfm at full lock, electrics fans, the best they can do is 5,500. Thats a 37% decrease, but still, will such little weight, it should not be heating.

I'm not sure what a cycling thermostat is.

 

I would have gone for 4th, get the rpms up a bit. But I agree with everyone else, you shouldn't have to with only 6000 lbs on, something is not right.

That is unless you're like me and everytime the gauge moves a hair above normal empty operating temp you freak out and think the thing is gonna explode. Nah that's probably just me.

 

I would get rid of the electric fans, they don't pull enough air even on a good day.

Jeff

 

Possibly a bad radiator cap? I would check that first.

 

My first thought is head gasket. I see your sig says timing at 18*, not sure if that is to much for towing or not?

 

The timing is one of the factors here. Yes, the electric fans are forfeiting some airflow. But at speeds over 40mph or so, fans contribute VERY little to cooling at all-- incoming airflow equals or surpasses what even the oem fan can do.

But that 18* timing is too much for towing unless you are ripping along at 2500rpm all the time. The advanced timing puts more heat into the pistons and rotating components of the engine.

Back that timing off to 15.5 and see if the overheating goes away.

JMO

 

My water pump is never been changed far as I know does not weep at all

I am going to back my timing down to 15.5*

Radiator cap is new after the incident

 

Set timing to 15 and wow what a big difference! I was having to turn on my fans while feeding now the temp does not even move. much more low end now and seems to me that it smokes less when its not up to normal temp. Have not towed over any mountains yet so don't know how much it helped out but just driving over the same hill that made me overheat towing 6000 lbs egt's seemed to be less.

Is this because the engine is more in its powerband at 1750?

Runs cooler idling and goin slow because of less timing?