Mixing oils?

You should not ad (sic) synthetic to dino oil. You should also avoid switching back and forth. Keep in mind that you probably found a synthetic blend on sale.

You need to commit to one or the other, and which one you like is a matter of debate. But once you decide, stick with it. Do not mix and do not switch back and forth.

The question is moot unless it is a real synthetic oil you are talking about. Real synth is groups IV and higher fake synth is group III. Unfortunatly you can never know for sure if what you bought is synth or not as the makers and mixers "Ain't sayin'."

No actually Costco has a nice $9 off coupon for Mobil 1 ( box of 6 ) making it right around $4 a bottle, the same as the Motocraft I bought. Both are API SM Energy Conserving.

Above.

Thanks Ed. Looks fine.

How come?

Mobil 1?

Most grades are group III base stocks, the exception may be the 0W40 because it is the only one I've seen (so far) that carries ACEA approvals.

"Jane_Galt" wrote in message news:5KadnRcXsbpD_U7RnZ2dnUVZ snipped-for-privacy@forethought.net...

This is what people used to claim when Amsoil and Mobil 1 first were marketed (particularly Amsoil). One claim was that the synthetic oil would disolve any old deposits left by conventional oil and that in some cases this old crap was all that was preventing oil from leaking from seals and gaskets. Maybe this was true, but I always doubted it. At least for me, engines properly maintained with conventional oil didn't usually have a lot of deposits to be disolved. I think it was more likely that the early synthetic oils had significantly lower viscosities than the conventional oils they replaced (particualrly when cold) and this made the rate of leakage out of old seals and gaskets much higher. There were also claims that the additive packages used with some of the early synthetic oils were incompatible with the additive pacakges used with conventional oils of the same period and in some cases the synthetic oil additive packages were incompatible with the seal materials used in engines of the period. Mostly these claims were associated with Amsoil products. I have no idea if they were true. Another claim back then was that you needed to break the engine in on conventional oil before switching to synthetic oil which seemed at odds with the claim that you need to stick with one or the other. I also always suspected that the synthetic oil marketing people (particaularly the Amsoil sales people) promoted the idea that once you switched to synthetic oil you could not switch back as a way of discouraging peopel from going back to conventional oil once they failed to detect the huge benefits claimed for some synthetic oils.

These days, at least in the case of major oil companies, they don't claim there is any danger in switching back and forth between conventional and synthetic oils. In fact a lot of oil that is marketed as "synthetic" in the US is really highly refined dino oil. It may still have very good properties, but at least compared to the original synthetic oils it is not truly synthetic at all.

From

Question: What Will Happen Switching From Synthetic Motor Oil to Conventional Oil I have been in the mechanic business for 8 years and was always taught that you cannot go back to conventional oil from synthetic oil. I have seen the damage caused by going back to conventional. Is it true that you can switch back to conventional with no damage to your engine?

-- Jimi Peranteu, Essington, PA

Answer: Synthetic oils will provide better protection than conventional oils, but switching back and forth between full synthetic and conventional oil will not damage the engine. Of course, this depends on the current engine condition and the quality of the conventional oil being used.

From

: Myth: Switching between conventional and other types of motor oil is bad for my engine. Reality: Conventional, synthetic blend, synthetic, and high mileage motor oils are compatible. Mixing or switching between types of motor oil is not harmful to your engine.

From

FACT or MYTH? Once your engine gets a taste of synthetic motor oil, there's no going back to conventional oil. Answer: MYTH! Synthetic oil is compatible with conventional and synthetic blend motor oils. You could go back to conventional oil, but you'll miss out on the superior engine protection only synthetic motor oil provides. You wouldn't go from DSL back to dial up would you?

From

Mixing AMSOIL AMSOIL ASM is compatible with conventional and synthetic motor oils. Mixing AMSOIL motor oils with other oils, however, will shorten the oil life expectancy and reduce the performance benefits of AMSOIL. AMSOIL does not support extended drain intervals where oils have been mixed. Aftermarket oil additives are not recommended for use with AMSOIL motor oils.

Ed

Because.

As with many things in life, you simply need to make a choice and stick with it. You go to the same supermarket because you know it. If you have to visit a different one, there is a learning experience that you don't want to keep repeating. You go to McDonalds because you have decided that you like the menu better than Burger King, and on the occasions to visit BK, the menu is a challenge to navigate because you don't use it very often. Oil is a different thing than the supermarket and a burger joint, but the idea still holds -- you just pick something and go with it because of the familiarity and the desire to not reinvent the wheel everytime you undertake a project. Pick something and stick with it.

It's not a good idea to mix synthetic and dino oils for a few reasons, one of them being that synthetic oil depends on there being lots of it to get the best effect from using it. The deal is, they can make the synthetic oil molecules round so the oil rolls between the parts it is there to protect. Dino oil molecules are all sorts of shapes, so the protection comes mostly just from being there, not from being a favorable shape well. If you mix synthetic oil into predominantly dino oil, all you get is more oil but not the extra protection, and this is a waste of money because the synthetic is more costly. If you mix dino oil into predominantly synthetic then you dilute the extra protection of the synthetic, and this is a waste of money because the synthetic is more costly.

There are other more technical reasons to not mix oil, but this one should suffice.

You should select a motor oil brand that you have a preference for. You can study lots of online sources for motor oil studies if you need performance charts. I like to use Castrol GTX. Once you find the brand you think you like, then all you need to find is the proper weight for your car.

When oil change time rolls around, you walk into your neighborhood auto parts store and stroll over to the Castrol section and grab 5 bottles and a filter.

I dont know as much as you guys, but thought oils had detergents in them anyway, so if you changed them regularly, it was clean?

Ah.

Heh heh.

Ahah! Thanks for that Ed. :)

But really then, there's no point in even getting the Mobil 1 on sale at Costco for $4 a bottle, when I can get the Motocraft for that and they're both API SM Energy Conserving.

In fact it would probably be best to keep an eye out at Autozone for any sales on the latter, for even less?

Wonder if they have a sale email thing that you can mark for a product you wanna keep an eye on?

LOL Why? I'm a libertarian type, remember. I question everything.

Not much in life, that I can see, that I HAVE to make a choice and stick to. :)

I'm not convinced.

Speaking of that, how hard is it to reach the oil filter on my 02 Corolla?

Wonder if I should do my own changes, instead of leaving it to haphazard on what the mechanic uses?

On the downside, I'm fat and 62, dont crawl under stuff so well anymore. LOL

I don't know how difficult it is to reach the filter on your Corolla, but on my BMW it's _very_ easy. The filter is on top, and lives in a can that holds the oil when the cover is removed. If I wait a few minutes after taking the cover off, the oil will drain into the engine so that just a few drops fall off of the filter when I take it out of the canister.

If you are taking the car to the corner for an oil change, then you're not getting synthetic motor oil for $19.95. Synthetic oil has a retail price of almost $6.00 per quart, and you need five of them. The oil change joint wants to make money on the transaction, so you should consider the price they get to be closer to $7.50 per quart, plus the labor rate to put it in.

Given the advanced age of your car, and the fact that it's an econobox, and that you take it to the oil change joint for new oil, I'd not even consider synthetic motor oil. Buy a case to keep at home to add a quart on occasion if it is necessary.

When you mix synthetic and regular motor oil you are not only diluting the excellent lubrication propertes of synthetic motor oil, you hare also losing the added advantage of cold temperature oil viscocity. During the winter regular oil gets thicker and may even gel as the temperature drops. Synthetic oil remains very fluid to a very low temperature, so there is very little wear and tear to your car motor, starter and battery. Consider the added cost of full synthetic oil as an insurance policy for cold weather startups. Your car will start up faster and easier saving you from other maintenance costs and wasted fuel.

I always thought synthetic blends were a marketing scam.

Or I can use 5W30.

We dont live in Alaska here. It rarely gets to 0.

Dont know.

I'm in Canada and see anywhere from -12C to -40C during the winter months. Even regular 5W30 will get very thick if your block heater is timed to cycle or not plugged in under these conditions.

So stick with one oil, one restaurant, one grocery store, one doctor, one . . . . . . . . . . . . . .

Can you cite a real reference for this interesting Amsoil propoganda?

My experience with the pros: overfilled by 1 full quart overtightened filter TWICE to the point I had to demolish the filter to get it off, it was metal to metal! b-i-l drove off and totalled the engine (drove about 2 blocks), forgot to put the plug in and the oil drained straight out, they didn't check the level obviously

It still pours slowly at freezing temps. Synthetic pours normally at 10 degrees while regular flows noticeably slower than in the 60's. That is why I personally stick to synthetics.

I can't even cite Amsoil.

I think that any additive is snake oil, and one is throwing good money after bad when they use this stuff.

I do have one notable exception... If you have sticky lifters that have gunk and goo built up inside of them, you might find relief from the noise with an additive that removes the gunk and goo. But, if you have sticky lifters that you want to clean up, you can usually do it with a pint of automatic transmission fluid added to the motor oil for 500 to 1000 miles before an oil change is due. ATF doesn't really qualify as an additive though, so the exception isn't all that notable in the long run.

But the discussion is about a person that says she got a good buy on some synthetic (she did not specify if it was synthetic blend or pure synthetic) motor oil and wanted to put some in as her consumed oil during the normal course of driving. I maintain that one should use synthetic or not, but not mix it because mixing oil is a waste of money. If one has a crankcase full of dino oil, a random quart of synthetic is not worth the cost of the synthetic, and if one has a crankcase full of synthetic, why dilute with dino oil and remove a portion of whatever good the synthetic oil brings to your engine?