Have a U320 with the m11 engine
Last year even in very hot temps and hillsides etc the water temp never rose above the 200 mark
Today returning from a short long weekend adventure the temp was at about 210ish for the entire trip. The outside air temp was about 50 and i was doing about 60 mph
The fluid looked ok as far as the level in the reservoir. I am not sure of when the radiator was ever services as i have not done it in the 4 years of ownership.
What should i be looking for to begin with and IF it requires a flush... anyone have the procedures to do this I am kind of an amateur mechanic at best
Just throwing out a couple of places to start. First I'd check the thermostat, it could be not fulling opening. Second, check your fans to see if they are running correctly.
As for flushing, do a search for radiator flush. You should see a very comprehensive thread written by Brett that thoroughly details the flush process.
Peter,
Were you reading these temps. on something like the VMSPC or the dash gage?
Mike
I did edit it to show the temp as 200 last year ( fat fingers)
Mile the temp was read through my dash gauges
So chuck...is a normal operating temp between 190 and 220. ? I thought that anything over 200 was bad?
Do you have an electronic controller or a wax fan controller?.i had to replace my electronic controller last year for a wax controller.. Next time out and it's running hotter than normal if you have the electronic controller pull over and unplug it and continue on and see if the temp comes back down to normal, if so the controller is bad and not ramping up the fan speed when needed
Keith
Oooh k. Where is the electronic controller?
Google AI (FWIW) says:
"The normal operating temperature for a Cummins M11 diesel engine is generally between 190°F and 220°F (88°C and 105°C). While the engine should maintain a temperature in this range, it's not uncommon for heavy haulers to reach 230°F (110°C) under demanding conditions, especially in mountain grades. Fan engagement is typically around 212-215°F (100-102°C), according to Cummins. "
See thread linked below for more opinions:
M11 Celect Plus Coolant Temp on Grades (https://www.foreforums.com/index.php?topic=31938.0)
Yours is a wax valve system. Yes they do get old. The wax valve causes restriction to the oil flow to the fan speed regulator. No restrictions means low fan speed. Hi restriction means Hi fan speed. I installed a needle valve inline with the wax controller line so I can manually override it to the hi speed position if desired. Several other issues could be Fan blade condition, and need to know radiator fin condition. If you have used radiator stop leak the transmission cooler is subject to get plugged. Cleanable issue
I have followed Scott's lead with the wax valve and a needle valve with a 12v cutoff valve wired to a switch on the shifter panel so that I can activate the fans to max on any time I feel the need. I've been struggling with high temps on hills since I bought my coach in 2019. The coach will shut off at 222. The previous owner told me he had the radiator "redone" but no receipts to show it. I have flushed cooling system, replaced the thermostat and cleaned the bars leak out of the trans cooler also removed the water pump to inspect the impeller. I've requested from Brad a new radiator a few months ago but unknown how long that will take. Could be a year. I've learned to manage the temps. with backing off keeping RPM's up around 2000 and end up on 6% grades down to as slow as 35 MPH. A bit frustrating but I keep telling myself I'm not in a hurry. Jim.