Purchased in Nov.
Unit has a Cummins ISC on a Freightliner CC.
AT 68 to 70 mph engine temp.warms to 216 and the cooling fan ROARS to cool down to 174 degrees. This happens about every 8 to 10 minutes.
Anybody else having these problems...?
Just wondering why FL didn't use a variable speed fan clutch to better control engine temperature?
Current Cummins printed material says 180 thru 200 is operating temp.....suggested?

I believe you have a side radiator with a fan clutch. Be sure that the temperature you are reading is correct. Dash gauges are not always that accurate although the sender is. An engine monitor will give you the full accuracy. I don't have a side radiator but for sure the fan should come on well before 216 degrees. You can find a lot of good info by calling Freightliner Customer Service at 1 800 385 4357. I have made a lot of use of that number on my XCS chassis.

Thanks for the ideas but this rig is a rear radiator and FL inspected the MH on March 4th.
According to the Official report.......everything is "within standard limits".
If a variable speed fan clutch was programed to respond to engine temp. and not design limits just on and off [ like mine now ] it wouldn't be a problem. Cummins states in the Owners manual thatoperating the engine over or below 180 to 200 degrees could DAMAGE the engine.
Why would FL not care?

Have you called Freightliner customer service? It is free and very helpful. You could have a bad thermostat that opens at too high a temperature or opens only partially. When the temp gets high the fan may go to its max speed. I don't have a temp controlled fan but I have a rear radiator and a fan that is on all of the time. You have something wrong for sure. When I need help I call customer service and then decide if I can fix it myself or take it to a dealer. I rarely resort to using a dealer. You can change your thermostat relatively easily if you have the access. It is on the engine end of the upper radiator hose (the large one on top of the engine going to the upper radiator).

I have a 2008 Freightliner chassis with the ISC too and your fan operation sounds normal to me. I have watched mine carefully and the fan comes on at 212 approx and cuts off in the 170s. Depending on the weather speed etc this dictates how often the clutch fan operates. On older models they did not have the clutch at all and the fan stayed on robbing the engine of HP etc.

Did you use the search feature? I think if you do you will find several threads on this topic and most of them all have similar operation to yous and mine. I dont even hear my fan unless I have the camera audio turned on.

Just saw your post about cooling temps. I have an 07 Monaco camelot with a 400isl that is doing pretty much the same thing. I has a side radiator though. Just curious if you found the source of the problem

quote:

Originally posted by capt cook:
Purchased in Nov.
Unit has a Cummins ISC on a Freightliner CC.
AT 68 to 70 mph engine temp.warms to 216 and the cooling fan ROARS to cool down to 174 degrees. This happens about every 8 to 10 minutes.
Anybody else having these problems...?
Just wondering why FL didn't use a variable speed fan clutch to better control engine temperature?
Current Cummins printed material says 180 thru 200 is operating temp.....suggested?

I read your post in May and having purchased a new Damon in March was interested in the problem. Recently on I-77 from Statesville NC to north of the Virginia line (Fancy Gap etc) I began to notice the same thing. Temp cycles up and then cools back down. Figured if there was going to be a problem, it would show up when we crossed at Fancy Gap. No problem, no heating or anything. I figure this is the nature of the beast and the thermostat is doing it's thing. Bothers me, but apparently this is normal.

Not much feedback from the OP. I have a rear radiator with the fan on all the time which does take some power for sure, but it does keep the temp very steady, 180-190 deg. I am barely over the cut-on temp of the thermostat. I have wished for a thermal controlled fan clutch but I would not want one that is simply on-off. The temperature cycling of the engine would seem to be detrimental to its life. In any case getting an accurate temp reading would be very helpful. Silverleaf is a much better readout than dash gauges which can be worthless.

I believe that FL just went CHEAP with the fan clutch. I also believe that excessive heat or LACK of control of that heat will ultimately damage the engine. I now have 18k on this coach with the fan still ROARING.
FL uses a fan clutch from Horton and they are now shipping a variable speed clutch that will be controlled by the ECM.
I'm torn between ordering the new clutch, adding aux. electric fans or trading to another unit.

capt, the bottom line is, is the new ecm controled fan clutch worth over $2000 installed. My opinion is, I think not. My direct drive Cat fan has the coach running at a pretty steady 190. She only varies between 188/190 cruising and 194 on long hard grades. I think I will leave well enough alone. The fluctuations you guys are seeing is the thermostat doing its job, nothing to worry about.