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Question for Mikee

Yahoo Message Number: 70983
What is a safe upper temp. for a diesel? Thermostats are 190 degrees. In a gas rig, holding 220 degrees on hard pull is a good temp. Is it different for a diesel?

Leonard

97' Magna 5418

Re: Question for Mikee

Reply #1 –
Yahoo Message Number: 70985
Most current diesels have a 190 or 195 thermostat, temps up to 210 are not unusual. 220 to 225 on a hard pull are typical.

Mikee

Re: Question for Mikee

Reply #2 –
Yahoo Message Number: 70986
Thanks, that is inline with my thinking. So many of the running hot post are not running hot, but normal. What I do not understand is why CC has alarms going off just over 200 or so. The BIG thing with diesel is cool down time before shut down.

Leonard

97' Magna 5418

Re: Question for Mikee

Reply #3 –
Yahoo Message Number: 70988
Leonard I just read somewhere recently, and don't recall where , that cooling the diesel down, is a myth- basically a waste of fuel.. I can't recall the specific reason. I don't wish to engage in a war over this, just telling you what I read.
As well , a couple of other points. If you are reading the temps etc from the Silverleaf, the alarms can be set to your liking. My ISX came with an oil alarm temp set at 230, and on a hard pull the alarm would go off. If the water can be at 220 safely on a pull ( and I believe that is not a problem , as long as , not consistently ) then it is easy to see oil temps 20deg warmer, since the oil is right in touch with the hottest parts. I reset the oil alarm to 240 and have not had a problem since. Change the alarm settings on to a bit higher than it is currently set, and observe. Someone mentioned that water temps went down to 165. I would see that as a problem. That would cause an increase in fuel consumption. Diesels run , as Mikee said at 190 or 195 thermostats. The reason is, that since there is no spark plug , the diesel is ignited by the heat of compression. If you run the engine cool then it will not ignite as easily. That is why the older , non computer controlled engines smoke at start up.

Ron Baran 09 Magna 7025

Re: Question for Mikee

Reply #4 –
Yahoo Message Number: 70990
It's the turbo that needs cool down. See what happens to a turbo running cherry red shut down improper. I had one on this used CC. Cracks all over the exhaust side. Shot turbo. Expensive repair. Fuel much cheaper. Some newer units have water cooled turbo's. Not so critical. Another reason to allow cool down is for the turbo to spin down so when the engine is shut off and the oil pressure drops the turbo bearings are not spinning without lube. Have rebuilt plenty of turbo's where this was not done. Sure takes out the bearings. Pull into a truck stop and see how many truckers shut off the engine while fueling, none. They are cooling down the engine after just coming off the road. Have temp. gauge on my turbo exhaust. Some times the temp can be 500 to 600 and more degrees when I stop. Off freeway to rest stop for example.

I would cool down a hot gas engine as well after a hard pull, not one just cursing down road. Diesel more important for above reasons. Most times, by the time one gets off the road into a parking spot, things have had time to cool down, but not always. Don't know where you read about the "myth". What every the source I would question it.

Leonard

97' Magna 5418

Re: Question for Mikee

Reply #5 –
Yahoo Message Number: 70991
Quote
Quote from: Leonard Kerns
Well goes another view. My Cummins ISL has a 180 degree thermostat and Cummins tells me that is the correct one. I am running too cool and wanted a 190. Can't find one for the ISL. Cummins does not even show a part number for a 190. Thursday I am going to change my thermostat for the second time. The first one stuck closed and this one seems to be stuck open. I rarely go over 176 degrees.
Lyle Wetherholt
04 Intrigue 11740
> What is a safe upper temp. for a diesel? Thermostats are 190 degrees. In a gas rig, holding 220 degrees on hard pull is a good temp. Is it different for a diesel? >

Leonard

97' Magna 5418

Re: Question for Mikee

Reply #6 –
Yahoo Message Number: 70992
Some engines have seals around the thermostat. If they are bad then the thermostat cannot do it's job. Might check for seals when you have it open.

Leonard

Re: Question for Mikee

Reply #7 –
Yahoo Message Number: 70996
The manual for my ISL says that the thermostat is full opened at 195. It does not start to open below 190. The Silverleaf reports that the combination of the fan controller and the thermostat run normally between 190 and 200. Up and down. Over and over.
Have you looked at your manual to see what it says about the thermostat.
If my engine was running as cold as yours I would know what it was. I would be the fan controller running full time on high.

George in Birmingham
'04 Allure 31038
George in Birmingham
2003 Magna 6298

Re: Question for Mikee

Reply #8 –
Yahoo Message Number: 70997
The cool down period is not for the engine, but for the turbo, 3 minutes is necessary to dissipate the heat the turbo creates when it is working. That being said, most of the time when exiting the interstate, driving to the fuel pump, etc gives you the time needed to cool the turbo , as long as it is a 3 minute period.

Mikee

Re: Question for Mikee

Reply #9 –
Yahoo Message Number: 71015
According to CAT and Colton, you and Mikee are correct: This notion that yor engine coolant should not go over 190 is false. In fact these engines operate more effeciently around 200, especially under load. Another relevant issue which people seem not to raise is whether you A/C is on or not: In a CAT with separate sensors for the cooling fan, this has a profound affect on temps, at least on my engine, since the cooling fan is close to locked on high. When my A/C is on, the temps rarely go above 188-190 no matter what. If I turn the A/C off, on a warm day they cycle between about 188 to 210 depending on load.

Rich 2002 Magna

Re: Question for Mikee

Reply #10 –
Yahoo Message Number: 71016
Lyle,

I also just changed the thermostat in my ISL 400 and at the same time converted to an extended life coolant. I gave Cummins my engine serial # and they gave me 180 degree unit. On a recent trip the coolant ran pretty consistently between 190 & 195 degrees according to the Silverleaf when running between 55 & 60 MPH. Thought this info might be helpful to you

Fred Compton

02 Intrigue # 11407