Community Forums

Wicked Whippets · 01-20-2009, 06:50 PM

I have an ISC 350 in a 2004 Winnie Vectra. I can't find what the normal operating temperature range (water temp) should be for this engine.

I'm heading out for Denver in a couple weeks and wanted to know at what temp I should be shifting down to increase RPM in the mountains.

Please don't flame me...I searched the forum and couldn't find it here or on the Cummins site.

FleetMan · 01-21-2009, 06:31 AM

A diesel engine normally is most efficient operating at approximately 195 degrees. Most manufacturers "shoot" for that range. My ISB, under normal conditions, runs at 192 to 196. A clean radiator on a DP is important to proper cooling system operation.

AFChap · 01-21-2009, 10:22 AM

If you depend on temp as a shift indicator, you will be behind the power curve. Better to use engine RPM as the primary indicator with a second eye on the engine temp to verify you are ok. My goal is to keep my ISC 350hp at apx 1900 RPM or higher while in a hard climb.

Wicked Whippets · 01-21-2009, 04:51 PM

Yesterday, while climbing the hills from Phoenix to Prescott, the ISC would briefly hit 205 or so, then dropped down into the 190s.

So what is the SAFE operating range (from this temp (low) to this temp (high)? In other words, at what point to I start to worry and at what point would I want to park it by the side of the road and let it cool down?

As you know, there is no "yellow" or "red" zone on the temp guage. I generally use the engine status on the backup camera display to monitor temps etc.

AFChap · 01-21-2009, 06:01 PM

I don't have any engine status on the backup monitor. I rely only on the dash gauge.

I don't recall seeing a posted normal operating temp range for the ISC, but for another Cummins engine I recall between 158°F and 212°F listed as normal.

My ISC normally runs somewhere around 180 or so. I have seen it creep slightly above 200 in some severe mountain climbing (normally when I was in 4th gear). Slowing to downshift into 3rd to raise the RPM kept the temp from getting any higher. My temp gauge is marked to 250. Personally, I wouldn't ever let it get beyond 225 without pulling over to cool down -- that would be exceeding my comfort level!

chasfm11 · 01-22-2009, 03:46 AM

Last year, I replaced all of the hoses when I did a complete coolant change on our ISB. Because I was concerned about air pockets that I might have created during that process, I began monitoring our coolant temperature very closely, using our VMSpc window. What I observed is that our 5.9 ran around 185 but would climb to 194 when the thermostat opened. Even during climbs, I never saw higher than 197 before the engine would start to drop.

Is this normal? I don't know, especially since your ISC is a bit different than our ISB but I thought I would share the experience. To me, the important part is that the thermostat is working correctly and that I know what the "normal" upper limit is. It is like the turbo boost gauge. I monitor it to make sure that, when I'm pulling hard, it is in the 22-24 range. It is when an engine starts operating outside of what I'm used to seeing that I get concerned.

Charlie

Wicked Whippets · 01-28-2009, 04:26 PM

I contacted Cummins and this was their response...

"The maximum temperature the engine can reach is 225 F. At this point the engine starts to set fault codes and will likely derate its power output in an attempt to save itself from a dangerous overheat. Normal temperatures are anywhere from 190-210 F."

Roadking · 01-30-2009, 01:38 PM

I have the 350 ISC with a side radiator. My temp cycles between 195-205 as the computer controlled hyd. fan kicks in and out. I'm pretty heavy and even when climbing hard on 6-7% grades in hot weather the temp is fine. The fan kicks into high speed but the temp still stays below 205. Cummin's and the Sparton chassis folks did a great job on meeting the cooling requirements.

AFChap · 01-30-2009, 05:05 PM

Quote:

as the computer controlled hyd. fan kicks in and out

Roadking

I have the same chassis, and was not aware we have a multi-speed fan. I have heard of owners having a kit installed to make the fan thermostat controlled ...did you have that option installed? Can you hear the difference when "the fan kicks into high speed" ? If not, how do you know? I can hear fan speed difference with engine RPM, downshifts, etc but have not noticed other changes in pitch that would indicate a change in fan speed alone.

Roadking · 01-31-2009, 06:29 AM

I'm only guessing on the multi-speed. In warm weather the fan seems to make a lot of noise whereas in cooler weather the fan noise is much more sub-dued (sp? --and to lazy to check). I notice this while driving and I have also walked to the back (while the DW was driving) and listened to the various sounds and the fan seems to make more noise in the summer. Of course my memory from winter to summer is always questionable!! Also, I have always had a slight "kick" in the steering wheel when the fan kicks in which I assume is due to the change in hydrallic pressure from the fan motor load. Anyway, this slight "kick" seems to be more significant in the summer/higher heat times than in the winter, or cooler temps. I'm wondering if there is a way to really tell?

AFChap · 01-31-2009, 03:39 PM

Roadking

I think we have a single speed fan, but after getting rolling it shuts down (higher gears) and then it will kick in at just over 200 degrees or so to provided needed cooling. Mine howls quite a bit on start up but then dies out over a certain RPM. I recall seeing some discussions about owners paying $500+ to add a "kit" that causes the fan not to run at all unless the thermostat needs it, and may also make it a two-speed when it is called on. That makes the rig quieter at low speeds and also provides more horsepower. Maybe someone else can confirm what we do have.