Oil gets darker sooner with Dino over Synthetic

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Jul 13, 2003
I switched over from M1 5W30 to Exxon Superflo 5W30 in my 99 Corolla a couple of months ago.I have used M1 in the motor since I bought it new and it currently has 49k miles. The M1 usually took 3K miles to start darkening to a light brown color from it's original gold color. The Exxon Superflo however takes around 600 or so miles to notice a color difference from it's original golden color.By 1500 miles it's dark brown in color. Does this really mean the Superflo is cleaning better than the M1 ever did or is it oxidizing faster? [I dont know]
My 4Runner had 23K miles on it when I bought it. After the first change to M1 I noticed it got dark quite fast. Subsequent changes and it seemed like it took longer and longer to get dark. Adding 3oz of Auto/Rx and it got darker faster...
Originally posted by Alan: -*-* The Exxon Superflo however takes around 600 or so miles to notice a color difference from it's original golden color.By 1500 miles it's dark brown in color. -*-*
Good, sound like its is a god ol Dino at work here. Dark oil means its been cleaning... and 1500 miles... JUst how dark brown in color? How does it feel and smell? Done the Poor mans blotter test>? The water test? NO, I wouldn't worry!
Is this one of the sludge engines? At any rate, dino oil is more susceptible to heat degradation than synthetic and as the oil breaks down it looks darker. As far as the cleaning properties of M1, I had a badly sludged 305 GMC truck and in 30k miles of Synthetic it cleaned the heads so the were totally sludge free.
I've noticed the same in my Corolla, 1994. I just put Mobil 1 10w-30 in for the first time. I thought it was getting darker faster, but I have about 1,000 miles on it now, and it's just barely starting to turn a darker amber color. With regular pennzoil, it would pretty much start to turn a very dark amber after only 500 miles or so. [I dont know] Maybe Mobil 1 really isn't a good cleansing oil. I did run Auto-RX before installing the Mobil 1.
This isn't considered a sludge engine.I'm pretty sure no oil would sludge in this motor with sensible use. [Patriot]
You're just seeing rapid oxidation with the petroleum oil ...it's easy to reproduce this effect with a simple demonstration test .... Take two small tin cups and pour 2-3 ounces of Mobil 1 ,Redline,Amsoil etc in the first and 2-3 ounces of any petroleum oil or synthetic blend in the second. Fire up the grill with the cover off and place both samples equally on the burners. Cook them on high for 20-30 minutes to accelerate the oxidation rate and see what you find. When the petroleum sample starts smoking badly, turn down the flame so it doesn't flash.... The comparison and visual condition of the synthetic vs the petroleum lube is generally pretty dramatic ...Even If you compare a group III oil to a PAO/Ester based synthetic, you will see a significant difference in how the two thermally decompose .... Tooslick www.lubedealer.com/Dixie_Synthetics
Alan, I think what you are seeing is the ability of the dino oil to suspend dirt particles. Dino oils are better than synthetic oils at dispersing dirt! That's why they get darker quicker.
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