Dino vs Synth Volatility / Evap / Volume Reduction

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Apr 10, 2004
I am rather new to this site and enjoy it! I am also in the process of switching to M1 in my '97 Camry from Dino. I have had good results from Dino with 3 month / 3K mile OCI for its entire life, and I recently verified that my engine internals are not slugged at all, a big concern for this particular engine! One of the reasons that M1 appealed to me is Mobil's claim that it is much less volatile and will only experience ~50% of the volume reduction of Dino. I carefully measure the oil I pour into my car everytime I change the oil (I buy 5 quart jugs and I need 3.6 liters) and have wondered where the oil was going between changes since I have also measured the oil coming out of the oilpan + filter (trust me: no leaks / no burning). Note that I have observed this oil loss effect on a number of cars that I have had in 30 years - it never occurred to me that the lighter components of motor oil are actually so volatile that they "evaporate" and get pulled into the PCV system! I have noticed the PCV valve and associated tubing have oil in them, but not blocking anything. I was not concerned because every car I have ever owned had this --> now I think that this is "volatized oil" and this oil will aid the formation of intake and combustion chamber deposits for a frequent oil-changer like me! Do you all agree? In your experience do you agree with Mobil's claim that M1 does not volatize like Dino and I should observe much less oil volume reduction between oil changes? This of course assumes no leaks or burning. Best wishes as you motor along! SWS
The big advantage of M1 ss is the ability to extend drain intervals vs. a regular SL dino oil. Under harsh driving conditions there will be less evaporation of oil with the synthetic but for day to day driving I think there is little difference in evaporation, and engine protection while using a good dino oil. As long as you keep short intervals a good dino like penz. castrol chevron or quaker state will do a good job. Now if you do want to extend drains and keep out from under your car the M-1 is the way to go. The modern dino oils will keep your engine clean and in good shape for years to come [Big Grin]
Glad to hear your Camry is beating the Sludge Monster, SWS! Due to the high speeds some engine components are moving at, I'd suspect there's a certain amount of basic oil misting goin' on as well, leading to small amounts of oil in the PCV system. In industrial machine shops, one can find evidence of such misting of lighter cutting fluids and coolants, and often you'll see point-of-operation air collectors to catch and remove such mists out of the air. What's in the PCV loop may be evaporated volatile components, or simply misted oil. Not sure really. But the detergents/dispersants in motor oil are designed in part to prevent this stuff from forming into sludge and/or deposits, and for the most part perform this task well. I didn't bother doing a quick Internet search to verify same, but you might find evaporation spec's in an oil spec sheet's "Noack % Off @ 250C degrees" and/or "Volatility % Evaporation @ 700F degrees/ASTM D-2887" numbers, although most oil spec sheets in fact don't include either number (Valvoline and Pennzoil do). You can plug "ASTM D-2887" into a search engine and see what comes up. Should the search somehow also come up with nude pic's of Britney Spears, please let me know!
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