Do you use synthetic oil?

[johnmyster]

Originally Posted by PaleMelanesian

And the conclusion was...

http://www.xs11.com/stories/croil96.htm

That refreshes my memory. 75 cabs. 60k miles each. 6000 miles of stop-idle-go per change with sliding lifters (they removed the stock roller lifters). 4.3 v6 Caprice cabs. 20 oils (2 synthetic) three engine treatments, etc. Lab tests, before and after measurements...

[PaleMelanesian]

Thanks! I've actually been looking for that report. I'm saving it now, for later reference.

Of the 20 oils we tested, nine were conventional 10W-30 oils, and eight were 5W-30. We also tested two synthetic oils, Mobil 1 and Pennzoil Performax, and one synthetic-and conventional blend, Valvoline DuraBlend; all three were 10W-30 oils.
...
One distinction: According to the laboratory tests, Mobil 1 and Pennzoil Performax synthetics flow exceptionally easily at low temperatures - a condition our taxi tests didn't simulate effectively. They also had the highest viscosity under high-temperature, high-stress conditions, when a thick oil protects the engine. Thus, these oils may be a good choice for hard driving in extreme temperatures.

So, the 10W synthetics flowed better at low temperatures than the 5w conventional oils.

As for the high end of the temperature range, I live in Texas...

[johnmyster]

I'm not convinced Texas engines run substantially hotter than NYC engines. They both have thermostats and radiators. 105 degree ambient summers in South Carolina and 65 degree Virginia days like yesterday, my temp gauge reads the same. Piston and valvetrain temperature are more a function of how you use the beast.

And I'm not convinced cold flow is really a concern. Bottom line is that you need oil pressure. An oil pump picks up a thinner oil easier, but it has a hard time maintaining pressure if the oil is thinner (it moves through the bearings more quickly.) Of course, my cars rarely experience starts below freezing, but really, if it's that cold, people use garages and block heaters.

Yeah, their test had some obvious holes. However, they needed a fleet of similarly driven, identical cars. But seriously, 6000 miles on a taxi is a ton of hours. What's their average speed? That's a lot of idling, and first gear grunting. If they didn't see differentiable wear under those conditions, then really. How many people would have guessed that the "superior lubrication properties" of synthetics wouldn't have shown up in this study?

I'll agree. Synthetics are shown to have lower viscosity changes across the temperature spectrum. Yes, they didn't really test that. As a scientist, I get paid to publish. Any responsible writer always has to acknowledge their holes and speculate possible findings under those conditions based on available data. They found that it's thicker when really hot, thinner when really cold - but someone's going to have to test if it makes a big difference under real operation. You can infer, but...

Personally, I want to have plenty of oil pressure hot and cold, so 10W-40 is my favorite for my operating parameters. Thinner would get better fuel economy, but I'm worried more about not-changing-my-engine economy. I watch my oil pressure gauge and decide what works best. I may even try 20W-50.

[Clev]

Originally Posted by PaleMelanesian

Thanks! I've actually been looking for that report. I'm saving it now, for later reference.


So, the 10W synthetics flowed better at low temperatures than the 5w conventional oils.

As for the high end of the temperature range, I live in Texas...

Good to know. I get both ends of the stick: snow in the winter and 110 degrees in the summer. I also change my oil at 5,000 miles because at 3,000 miles I'd be changing it monthly. Sounds like I should consider synthetic.

[trikkonceptz]

Here is a silly question .. Many of you claim to change the filter more often than the oil. How do you do that? By removing the filter don't you drain some oil along with it? ABout a quart or so? If so and therefore, do you add an additional quart each time you change the filter?

I was wondering because I would rather change my filter more often than do a complete synthetic change and let the filter go for longer.

[jamesqf]

So is there even a non-synthetic 0w-20 oil on the market? The only one I've ever seen in that weight (except for Honda's OEM stuff) is the Mobil 1.

And another thing that's always puzzled me: why can I find the 0w-20 at WalMart, but never in any auto parts store?

[IndyIan]

Originally Posted by jamesqf

So is there even a non-synthetic 0w-20 oil on the market? The only one I've ever seen in that weight (except for Honda's OEM stuff) is the Mobil 1.

And another thing that's always puzzled me: why can I find the 0w-20 at WalMart, but never in any auto parts store?

I think most guys changing their own oil stay away from 0W20, it has the rep of being factory oil to increase FE while sacrificing engine longevity.
From my basic understanding of how oil works I agree with that, now if they had 0W40 then I'm more interested.
Why its in Walmart I don't know, maybe walmart attracts people who change their own oil but follow the manufacturers recommendations to the letter.
I, like many "car guys" know better than the manufacturers... and I avoid walmart like the plague.
Ian

[thebrad]

Mobil 1 0w20/0w30

Have used Redline 0w30 in the past but stopped because I am not ballin' anymore.
Plus it's not API/SAE certified.

I will probably use a synthetic transmission fluid on the next service.

[metroschultz]

Originally Posted by trikkonceptz

Here is a silly question .. Many of you claim to change the filter more often than the oil. How do you do that? By removing the filter don't you drain some oil along with it? ABout a quart or so? If so and therefore, do you add an additional quart each time you change the filter?

I was wondering because I would rather change my filter more often than do a complete synthetic change and let the filter go for longer.

Short answer;
Yes.
in my earlier post I said I go 5k for filter and 10k for oil.
Top off after filter change. The Toyota filter only holds 1/2 quart.
S.

[trikkonceptz]

Originally Posted by metroschultz

Short answer;
Yes.
in my earlier post I said I go 5k for filter and 10k for oil.
Top off after filter change. The Toyota filter only holds 1/2 quart.
S.

Thank you ..