whats considered hot for oil temps

Originally Posted by gbrettin

High Temp motor oil Wear Testing-Myth vs Reality (very long) • Speed Talk

THERMAL BREAKDOWN

I also heated the oils and observed the temperature at which they started to vaporize/smoke, which indicates the onset of thermal breakdown. Thermal breakdown is the point at which the composition of the oil begins to change due to the temperature it’s exposed to.

The official test for this is called the NOACK Volatility Test. In this test, the oil is heated to 302* F for one hour. The lighter oil fractions will vaporize, leaving thicker and heavier oil, contributing to poor circulation, reduced fuel economy, increased oil consumption, increased wear and increased emissions. The test reports results in the percentage, by weight, lost due to "volatilization."

Before July 1, 2001, 5W-30 motor oil in the United States could lose up to 22 percent of its weight and still be regarded as "passable." Now, with GF-4, the maximum NOACK volatility for API licensing is 15 percent. European standards limit high quality oils to a maximum of 13 percent loss.

Here are the approximate observed temperatures at which the various oils started to vaporize/smoke, which indicated the onset of thermal breakdown:

5W30 Pennzoil Ultra, API SM = 280*

5W30 Mobil 1, API SN = 265*

10W30 Lucas Racing Only = 290*

5W50 Motorcraft, API SN = 275*

10W30 Amsoil Z-Rod Oil = 300*, the BEST in this test

20W50 Castrol GTX, API SN = 275*

5W20 Castrol Edge w/Titanium, API SN = 280*

10W30 Joe Gibbs XP3 NASCAR Racing Oil = 280*

5W30 Castrol GTX, API SN = 280*

10W30 Valvoline VR1 Racing Oil, silver bottle = 260*, the WORST in this test

0W30 Brad Penn, Penn Grade 1 = 280*

5W30 Royal Purple XPR = 285*


Here are the “averages” for the onset of thermal breakdown with these 12 oils:

Full synthetic oils = 282*

Semi-synthetic oil = 280*

Conventional dino oils = 272*

Originally Posted by IDZRVIT

That was published by 540RAT. Go on the Corvette Forum in the C3 section and see what they have to say about his oil wear testing.

Motor Oil "Wear Test" and "Lab Test" Data - Corvette Forum

There is more than one engineer in there who will not endorse his findings. Just sayin'.