12.7 detroit over heating...

Yep check the snsrs, dirty air filter or leaking charge air cooler and anything in between can couse overheat. Good luck..

 

Sounds like a tough one I'm not sure on the air to air if its running that hot and the fan wont bring it downbut worth checking sounds more like an air bubble from a leaking head gasket. Whats the HP rating and how much boost is it making under full load?

 

Also many Detroit's have a bleed screw in the thermostat housing Ive even seen them in lines to the sleeper on a international. Just seem like an air pocket problem. I had an over heating problem and it came on fast same symptoms but went and changed to an upgraded radiator that was spoused to cool 1100 HP and never ran over 190F again even on the hottest days. I run 180 stats and it runs at 180F most all the time unless i have a long hard pull. Maybe check the fan clutch as well i did have a guy with one that slipped real bad and he had your symptoms.

 

It's dam hot this year, just how hard is he pushing it? Might be as simple as dropping a gear or two. Coming out of CA and AZ sometimes 3. Keep RPM 15-1600, it increases water circulation and has more air going through the engine than at 12-1300 RPM. He replaced the radiator, but did he pressure wash(don't get to close) the air to air and a/c condenser?

 

the sensor in the thermostat housing sends the signal to the dash water temp gauge. the sensor in the passenger side head, sends signal to the e.c.m., to derate, kick fan on e.t.c. if you know your truck, you know when it is running hot or not. I always had better luck running 180's thermo's in my truck as apposed to the 190's that most folks will yell you ,IT HAS TO HAVE THE 190'S it was made to run at that temp. from what you post. I cannot diagnose it, but if & when it is fixed, post so others can learn. good luck to your friend.

 

Put a mechanical guage in it to verify the actual coolant temperature.

 

Overheating can be very hard to diagnose. you do not know who to listen to. everyone told me, do this, try that, it must be this, my 11.1 ser 60 has been running hotter than I like it for more than 5 years. no one can tell me why. I just quit asking & do what I need to do to offset the temp as much as I can. 6 or so years ago, I decided to let the fan work by itself & not use the manual I had installed. it worked just like it should. I thought. pulling 85,000 on a straight, with some rolling hills. the temp would get to about 215-220 the fan would kick on, the temp would drop quick, back to normal, fan would kick off. after 2 weeks of that. the head gasket went out.

did that cause it ? I have no idea, but since then. the ruck never ran like it used to. I know my truck. I know when something is not right, or at least the way it used to be. I put every part on it. or had it done. with a mil miles, I did not mind as much, cause things were probably at the end of their lifespan anyway. I put new water pump on, tried different thermostats, had air to air checked, new rad, new dash gauge, new coolant temp sensors, had a new fan clutch by masterbuilt installed, because I had an air leak there. cleaned the air to air & rad with a/c coil cleaner. even a inframe did not faze it. this started at about 800,000 miles, more than 1.4 mil now.

I used to climb mt eagle Tn & other hills, no matter how steep or how heavy, if I put the fan on it would bring temp down. now with the fan on temp still climbs. up & up. luckily by the time the temp is near 220-230 I am cresting the hills. any more & I would have to pull over. I run fan about 50 % of the time, when loaded. even at 60 m.p.h. at 215 degrees water temp, on a flat, fan will drop to 190 in approx 20 miles. it should not take 20 miles to reduce temp 25 degrees. the only thing I did not ever replace is the belt tensioner. but it seems to have tension. I have no problem in the winter. I would upgrade to a bigger rad, if I knew it would solve the problem. I lose no coolant either. I even thought about going with a heavy duty cac with a new rad, but the original ones always did just fine until one day. but like I say new rad was put in about 4 years 5 . may try to have it flushed out.