So I change the oil today, put in 3 gallons of Rotella, which really stinks by the way, I think I'll go back to the Valvoline next time.....anyway, I go for a ride tonight and my Commander is reading 209* while cruising down the road. Normally it's at 188* or so. The dummy gauge inthe dash cluster is reading like it normally does. What the h-e-double-hockey sticks? I also had the battery cables unhooked for about an hour while I finished up my Pacbrake install. You guys have any idea what could be going on?

 

mine never runs that cool, I'd say mine is more like 490*or so, my mount is post turbo.
[/IMG]

 

 

preloader,

I'm talking about the coolant temp, not EGTs. I probably should have specified!

EGTs are normal as is tranny temp. But for some reason the coolant temp is all screwed up.

 

The heat in the engine caused from combustion and in the turbocharger from exhaust will be the same when using both brands of oil, provided you are taking the same horse power and torque from the engine under both oil conditions. The temperature difference in the coolant is due to friction in the engine's and turbocharger's moving part's bearing surfaces and that is one area to consider. Also, depending on the oil brand there will be some difference in heat transferred into the oil that originated from combustion in the engine and heat transferred in cooling the turbocharger that originated from the exhaust passing through the turbocharger.

Are Rotella and Valvoline both synthetic oils? Synthetics lubricate better than conventional oils and some synthetic base stocks have better lubrication properties than other synthetic base stocks. Some synthetic oils with their corresponding additives will lubricate and transfer heat more readily than others.

My only experience so far is with my two tractors. I have been using conventional oil in both units for years and the first time last summer, which was hotter weather than usual, I used Amsoil 5W-30 synthetic severe duty engine oil. The diesel engines can pull harder and longer before they start to develope above normal heat on the coolant temperature guage than they did with 10W-30 conventional oil in cooler air temperatures. I know that there is a lubrication difference between conventional oil and synthertic oil.

I was using ESSO 0W-30 synthetic oil in a GMC 4.3 L V6 in the heat around Louisiana just before hurricane Dennis hit with slightly higher coolant temeratures showing on the guage, but no overheating resulted and the engine oil pressure remained good when the engine speed was increased. This year I am using the same Amsoil 5W-30 synthetic severe diesel engine oil in the same GMC gasoline engine with high oil pressure all the time. There is a completely closed winter front on the GMC because of our cold winters, but even on days that the outside temperature goes above freezing the engine coolant heat guage does not increase much or overheat at 70 mph on the four lane highway for three hours steady. With the ESSO synthetic I had to open the winter front, but it was 0W and the Amsoil is 5W. I like a diesel engine to run warmer as long as it does not get too warm.

 

So let`s get this straight. You changed your oil and claim it runs hotter.

What you did was add an exhaust brake and it runs hotter. How could you come to the conclusion the oil change caused this....
Now that I have had my fun...
The Exhaust Brake(PacBrake) will cause more internal heat due to the valve being in the exhaust stream.
Now you have had your lesson for the day. Never assume anything...

 

Well, not quite. I installed the exhaust brake last week. Today all I did was connect the wires. The obstruction has been in the exhaust stream for several days. Come on now, give me some credit. I may be new to diesels but I'm not an idiot...

I'm pretty sure the truck isn't running hotter, rather the gauge is reading wrong. I'm guessing that disconnecting the batteries may have reset something in the Commander, such as the model year of the truck or something similar. I'll run through the settings tomorrow after I install the new update.

 

When you power up the brake will it set(change)the blade angle.
Some actuators have a fixed(end of travel) position with no power and a set(default)position when powered. Thus adding to the confusion...
What % rate would you like your credit to be fixed @...

 

I tend to agree it's the commander guage. I don't care who's oil or if it's synthetic or not. A temperature of that swing running normal down the road is not caused by the oil your using. Unless your using Non-detergent oil from 1924.

 

The brake is held open by a spring and closed by compressed air. So, no, powering up the brake doesn't set a blade angle.

 

No, I know it's not the oil. It either is the Commander settings or has something to do with unplugging the computer. You know, I think I forgot to mention that. I had the ECM unplugged to finish up the Pacbrake install. But I don't think anything is wrong there because everything else is groovy.

I'll check the Commander in about an hour.....

 

Well I`m stumped. I have never run across this type of change by unplugging a PCM of unhooking a battery.
Sounds like your aftermarket stuff might be a little to sensitive to change...
Get an infrared temperature gun and match the sensor temps. This will answer your questions GrassHopper....

 

I'm sure you're right.

Well, thanks for playing the game Doc...better luck next time!

 

Okay, installed the update and everything is well now. I'm pretty sure disconnecting the battery caused the Commander to reset to he default setting which were wrong for my model year truck. Anyway......it's all good.

 

Glad to hear everythings good.