Oil Question

[forum15]

My questions is I have a higher milage engine (130k) and there seem to be a lot of oils on the market "formulated" for higher milage engines said to reduce oil consumption and lubricate seals and such. My questions is would a higher milage oil do anything better for my engine that a full synthetic like Mobile 1 would do? If anyone could help that would be great. Thanks

[sciguyjim]

With a high mileage car there are usually more spaces for oil to leak from and synthetic oil seeps into small gaps easier than petroleum oil so it may leak more. It can even create a leak where none exists now because they can dissolve some of the gunk which built up in the engine from the pet oil. In a high mileage car you would want to use a heavier oil to minimize seepage. Synthetic oil, while it does seep easily, does not oxidize or evaporate as much as pet oil so it won't burn off or create deposits as much (unless the car is burning a lot of oil.) Synthetic oil can cost 5 times as much as pet oil though so you may not want that expense for an older car. If you've been using pet oil, then stay with it and go up to the next higher weight oil. If you've been using synthetic, also go up to a higher weight, whether you decide to stay with synthetic or not. Also, if your car's burning oil, do you want to be burning up an expensive oil or a cheap one?

[454Casull]

Maybe they work - I'm not entirely sure. I do, however, believe this is the best oil around.

AMSOIL synthetic 10W-30

Additionally, you can replace your piston rings.

[forum15]

The car isn't burning any oil right now and is running great. It's been taken care of very well so I'm not worried about burning expensive oil. I guess what I really want to know is will synthetic do as much, or more good for my engine than higher mileage formulated oils.

[SaabJohan]

If the engine is running great, there is no reason to change oil type.

Synthetic oils are better, but older engines can get problems from them. But on the other hand they can also run even better. Sadly all synthtic oils aren't so synthetic as the manufacturers want us to belive.

Stay away from oils that contain solids like teflon. Teflon can be great as a coating or in grease but it certainly isn't in a motoroil.

[sciguyjim]

If we compare a synthetic oil and a high mileage petroleum oil of the same weights, say 20W-50, I think the synthetic will give more mpg, and better protection from wear just because it is more slippery. Over time, the pet oil will get thicker than the synth because it has volatile components which evaporate, unlike the synth. Then there's winter. The synth will definitely work better in the cold, even though it is the same "weight" as the pet oil. As far as I know, there is nothing special about "high mileage" oils, they are just made thicker so they don't seep out or evaporate as readily as a thin oil. Assuming both are similar in price, I'd go with the synth.

[enginerd]

Synthetic oils are overrated. Not worth the price for day to day driving. I have found no economic justification to switch to syn.

[454Casull]

I have found no economic justification to switch to syn.

There's never an economic justification to switch to something more expensive.

[enginerd]

Originally posted by 454Casull

There's never an economic justification to switch to something more expensive.

In some cases, there are. For instance in large diesel engines, the improved fuel economy you gain from synthetic oil is more than enough to offset the higher costs. Most of the time the higher cost is not justified. Lets say you spend 50$ an oil change for synthetic and 30$ for petroleum. 4 changes a year means the difference is 80$ in one years time. In ten years you will have spent about 800$ more for synthetic and both engines will/should be running fine. Most synthetic oils I have looked at and done research on don't yield more than 80$ a year in fuel economy gains. It's like spending 80$ a year to save 40$. I could be wrong or have flawed rational, but this is my opinion backed up by my experience.