Water temp on a 350

[jimbo2013]

I notice on my silverleaf the temp range goes 195-215

Never stay above 205 or so

Is this normal for it to go up/down that much,

[Mr. Dave]

My ISC 350 runs between 192ish and around 207ish on both the analog guage and my silverleaf. It moves up and down as the thermostat opens and the cooling fan runs (side radiator).

A couple of years ago I called Freightliner and asked if this was normal swing for the coolant temperature and was told yes.

Dave W

[clyon51]

As far as I am concerned, I would never worry about a 20° fluctuation. Especially going up and down grades as long as it didn't approach 'hot'. On long level grades, the themostat will create fluctuations by opening and closing. Is it possible you are paying too much attention to them actual temp? Rather than looking at the analog gauge? I know I did that too much when I installed a ScanGauge on previous coachs.

[jimmy braden]

Id make sure you got good rad airflow. In general older (not Common rail motors) like to stay in the 180-190 range. Much higher and you can get some hot spots on the cyl.. my side rad ISC only goes more than 180 on the steep climbs.

[jimbo2013]

this never goes below 185 in cold weather <40 degrees

It was 85-90 today it will idle at 190=193

[jimmy braden]

So is yours a DPF/SCR motor? What year is this?

[jimbo2013]

Originally Posted by jimmy braden

So is yours a DPF/SCR motor? What year is this?

DPF/SCR motor? what does that mean?

it's a 2010

[jimmy braden]

diesel particulate filter / selective catalyst reduction ...

And if its a 2010, the answer is prob yes to both... so it will run hotter.. Id say 205 should be common. I don't care for that myself.. diesels really don't work the same way as gas when it comes to pressurized cooling systems raising the boiling temp, so there isn't much margin once you get in the 200 range..

[jimbo2013]

Originally Posted by jimmy braden

diesel particulate filter / selective catalyst reduction ...

And if its a 2010, the answer is prob yes to both... so it will run hotter.. Id say 205 should be common. I don't care for that myself.. diesels really don't work the same way as gas when it comes to pressurized cooling systems raising the boiling temp, so there isn't much margin once you get in the 200 range..

You mean a filter in the cooling system?

[jimmy braden]

No, engines after 2005 have tighter emission requirements. Particulate filters in the exhaust system perform a scrubbing function when the buildup of soot exceeds a certain level. Also for 2011 and later (might have started as early as 2009 for some models), there is a urea injection.. which is even more aggressive for emission reduction.. But both add weight, exhaust restriction and heat to the engine. I would say it would at least operate 10 degrees hotter than a pre 2005 motor.. maybe 15.

[rodz]

My 2009 3933 does the same thing. Gauge constantly going from 180 to 210 and back. Hills or flat land doesn't matter.

[barmcd]

Mine stays pretty constant at 180 which seems pretty low to me. I've never seen it above 190, but we we haven't driven it in the mountains in the summer. Last October we went to Taos, Nm and it stayed at 185 all the way up the the grade to the mesa. I know side vs rear radiator makes a difference in cooling efficiency.

[Airstreamer6]

Quote: "...diesels really don't work the same way as gas when it comes to pressurized cooling systems raising the boiling temp, so there isn't much margin once you get in the 200 range...."

I think this is inaccurate. The pressurized cooling system is as important on a diesel and for the same reasons.

[jimmy braden]

The difference is diesels aren't designed to operate above 212 degrees gas engines are. Additionally, gas engine use higher jacket pressures by spinning the water pump faster so you get pressure that also.