Synthetic oil really do better?

[scott5]

Does the synthetic oil really do better than regular oil? I am not sure whether or not to use valvoline max life or just regular oil (my car has 149,xxx)

[terminaldegree]

There is Valvoline Maxlife, and then there's Valvoline Maxlife synthetic. Two different products.

Try doing a search. This has been beaten to death now. I don't think you should worry about it personally [run cheap stuff] until you've figured out your oil leak, otherwise you're flushing $$$ down the drain.

[96RS Alex]

Actually, the biggest factor in getting the best mileage with an oil is the ability of the oil to maintain initial performance during its service life. A good oil will maintain its viscosity, poor quality oils will either thin or thicken and performance will deteriorate. There is a large amount of variability in petroleum oils while true synthetics are much more predictable. This is one of the crucial advantages with synthetics lubes like Mobil 1, Amsoil, Redline or SynLube. Viscosity itself, if sufficient is not that great a determinant of mileage.

However, a synthetic base stock may allow a lower viscosity to be safely used.

20W is 20W. If it is sufficient for the engine, then it doesn't matter if the oil is petroleum or synthetic. Again, all that matters if the ability of the oil to maintain its performance during its service life. The trouble with 0W20 and 5W20 oils is that they are not sufficient for long engine life. The OEMs are not interested in your engine lasting 200K miles. They are interested in selling cars and trucks. In lab tests, the light oils deliver higher MPG by about 0.1-0.2 MPG but on the road, they don't provide any measureable benefit.

Thicker oils are better. What one loses in pumping losses is more than recovered in reduced friction.

[StormShadow]

all you need to know about oil is to learn how to read the back. On the back there should be something that is kinda in a circle. It will have a rateing. the higher the letter the beter the oil. Valvoline is usualy rated SL which is pretty much the oil standard to date. Now Mobile one is rated SM so it is higher quality. But guess what good old super tech at walmart is also rated at SM.

Also at your milage you might devolope a leak from switching to synthic oil. Synthic oil has alot detergants in it and your standard oil has produced some gunk in areas where it's protecting you from leaks. Clean it out and you might have a little leak problem.

[firebird925]

If you are thinking what is a good oil, then go with Valvoline I use the oil and I have a K&N oil filter and it goes smooth 10W30

[terminaldegree]

SM doesn't necessarily mean higher quality. SM oils are the new api rating for passenger car motor oil, and it specifically means that the additive package is different than the previous 'SL' stuff. I believe the primary reason for SM was to extend the life of catalytic converters, because SL stuff had too much of a particular Zinc-based additive.

The jury is still out on the 'SM' oils; generally speaking, SM will have to use better base stocks and less additives and SL is the reverse. [huge generalization]

Although there's nothing wrong with regular Valvoline, chemical analysis of it reveals a relatively weak additive package compared to its competitors. Hopefully the base oil holds up well.

One thing I look for when I'm buying synthetic oil is the GM 4718M rating, which is the Corvette spec for temperature stability.