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After a few posts reminding people that our oil temperature reading is actually the coldest place to read oil temperature, I decided to measure the oil temperature in the pan.

With an EOT reading of 208 *F (drove it reasonably hard), the oil in the pan was 250 *F.

That is 42*F hotter in the pan than the EOT reading. No doubt the oil gets even hotter at various places within the engine/turbo itself.

Also, when people see oil temps of 250 *F on the EOT, then the bulk oil is close to (maybe even at) 300 *F.

Glad to be running synthetic oil w/ a low volatility and fairly high flash point.
 

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I will never understand why they didn't use an identical setup to the transmission for cooling.
 

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What method was used to measure the engine oil pan temp?

If an infra red temp gun was used for measurement, they are not always completely accurate from my experience.

For instance, if you use one of these to measure cold ac vent outlet temp in which the actual air temp is 60F, it may read 27F with the infra red gun.

It dosen't surprise me though that the oil pan temp's are higher as that is the first place it's dumped after cycling through the moving parts.

Synthetic oil's with high flash point's like Delvac-1 ESP 5W-40 definitely gives me some piece of mind.

Good thread Mark!

Harry
 

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I tried my IR gun and did not get a reasonable reading. SO ................ I got a calibrated lab thermometer, took an oil sample, and read the temperature of the oil directly. I let the thermometer sit in the sample for 5 minutes and read the temperature. I watched the temperature for another 15 minutes and it did not drop more than a degree. I feel good about the accuracy of the reading.
 

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Your measuring in the right place and from what it sounds like a good sound method.

Most of our models at MBZ where I work, and all the hi performance AMG engines use oil pan sensors for oil temp and other measurements. Wonder why International did not do it this way?

I wonder how accurate one of these drain plug type temp sensors are here...
Oil Temperature Sensor | eBay
This would measure actual oil pan working temperatures.

This is not reassuring knowing or thinking about our 6.0L oil temps being this dramatically higher than what were seeing from the stock sensor location.

No wonder the injector orings dry out and crack on some trucks.

220F actual oil pan temps is actually ok, but 250F is not good, thats approaching the gray area, and 275F+ is where oil breaks down. When towing heavy in hot weather I can only imagine what the actual oil temps must be, they could possibly be reaching as high as 275F.

Alot of manufacturers use oil temp sensors in the oil filter housing area like our 6.0L, and maybe thats whats actually matters for the rest of the motor and hpop system.

But for the engine oil to hold up for any length of time, high tremps will shorten it's lifespan.

Our hpop system also subjects the motor oil to extreme high pressures, and high pressures create high temperatures, they go hand in hand.

Good maintenance practices are the best preventive steps one can take with these trucks.

Harry
 
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