Synthetic Oil Controversy

I've used synthetic oil (Mobil1 10W30) for absolutely years. Have had no problems except it keeps the internals of the engine clean! No sludge build up at all and I drive the car almost every day. Only thing I add is Lucas Zinc as it has flat tappets.
 
i am using Mobil 1 15w50 in my 1953 motor and it gives excellent driving and ideling oil preasure results and i get it at Walmart in a 5 qt gug at a reasonable cost... and it is high in zink also
 
Use Mobil 1 in all my daily drivers. I agree with the no sludge. Took the valve/cam covers off a few of the Toyotas I owned previously, I was amazed how clean the top ends where on both of them. They both had around 120K on them at the time.
 
I have used Mobil 1 in my modern cars for a long time and have gotten excellent longevity out of them. I use it in my Model A's, too. I have not put it into my V8s, yet. One has a bit of a leak, so I may not use it on that one, but plan to on my 39.
 
As a former MOBIL "service tech" AKA grease monkey. I have nothing but complete satisfaction with MOBIL1.
 
I don't think it's controversial. Most people agree synthetic is better except for a couple of factors:

1. It's so slick sometimes won't let piston rings "wear-in" and seat properly.
2. It lacks the additives (zinc & phosphorus) necessary to "hard surface" cams and lifters.

and also (which I'm not sure I believe) is that it leaks out easier from bad gasket surfaces.
 
I love using synthetic oils in my DDs but synthetic oil will leak out of even modern day cars. Had several vehicles, the mist recent a 2000 Accord with 85k on it. I had used synthetic oil in it for a couple years when it developed a leak. Several mechanics thought it to be a rear main seal leak and wanted to replace it. That might have fixed it but after changing to a non synthetic oil, the leak went away. Problem solved and cheaply!
 
TomT/Williamsburg said:
I love using synthetic oils in my DDs but synthetic oil will leak out of even modern day cars. Had several vehicles, the mist recent a 2000 Accord with 85k on it. I had used synthetic oil in it for a couple years when it developed a leak. Several mechanics thought it to be a rear main seal leak and wanted to replace it. That might have fixed it but after changing to a non synthetic oil, the leak went away. Problem solved and cheaply!
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Leaks explained:

A conventional 10w40 oil is a 40 wt oil with additives to make it 10w at low temperatures

A synthetic 10w40 is a 10 wt oil with additives to make it 40w at high temperatures
 
Get the TRUE facts on oil. I used Castrol 20/50 for 50 years
but switched to Valvoline the number one choice in the attached
tests. I like the Zink and Molly additives. It's an overkill but why
not add a few years to the engine life. G.M.
 

Attachments

mrtexas said:
Leaks explained:

A conventional 10w40 oil is a 40 wt oil with additives to make it 10w at low temperatures

A synthetic 10w40 is a 10 wt oil with additives to make it 40w at high temperatures
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I'm sorry, but I disagree with that.

The W stands for Winter, not weight. A 10W40 will flow at 10wt viscosity when hot and 40wt when cold.

All 10W40, regardless of what it's made of, will flow at 10W40.
 
Mike51Merc said:
I'm sorry, but I disagree with that.

The W stands for Winter, not weight. A 10W40 will flow at 10wt viscosity when hot and 40wt when cold.

All 10W40, regardless of what it's made of, will flow at 10W40.
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A multigrade oil is rated as how it behaves cold and hot.
You want it to behave as 10w cold and 40w hot.
The w is still weight just multigrade !
 
flatheadmurre said:
A multigrade oil is rated as how it behaves cold and hot.
You want it to behave as 10w cold and 40w hot.
The w is still weight just multigrade !
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Sorry flathead, the w is not for weight, it is for winter. And there is no such thing as 40w.

"When you see a W on a viscosity rating it means that this oil viscosity has been tested at a Colder temperature. The numbers without the W are all tested at 210° F or 100° C which is considered an approximation of engine operating temperature. In other words, a SAE 30 motor oil is the same viscosity as a 10w-30 or 5W-30 at 210° (100° C). The difference is when the viscosity is tested at a much colder temperature. For example, a 5W-30 motor oil performs like a SAE 5 motor oil would perform at the cold temperature specified, but still has the SAE 30 viscosity at 210° F (100° C) which is engine operating temperature. This allows the engine to get quick oil flow when it is started cold verses dry running until lubricant either warms up sufficiently or is finally forced through the engine oil system. The advantages of a low W viscosity number is obvious. The quicker the oil flows cold, the less dry running. Less dry running means much less engine wear."

"Obviously, cold temperature or W ratings are tested differently than regular SAE viscosity ratings. Simply put, these tests are done with a different temperature system. There is a scale for the W, or winter viscosity grades and, depending on which grade is selected, testing is done at different temperatures."
 

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Heat expanding polymers allowed multi-viscosity oils to come about. The term "Weight" was one added by consumers to describe viscosity but Society of Automotive Engineers are the ones that came up with the rating system. Engine lubricants and gear lubricants are both rated differently under the SAE. SAE 50 motor oil is roughly the same viscosity as SAE 90 gear lubricant. It gets even more confusing when you add in actual methods of finding viscosity of a fluid. ISO is the new rating system and that confuses things even more.

Synthetics will gain more popularity when they become the same price as natural fossil oil based products. Ester based stocks do find their way out of components much easier. Seals have to be very good design and quality to hold synthetics in. Hopefully they get better rather than worse. Things don't seem to keep going that direction very well.
 
donald1950 said:
i am using Mobil 1 15w50 in my 1953 motor and it gives excellent driving and ideling oil preasure results and i get it at Walmart in a 5 qt gug at a reasonable cost... and it is high in zink also
Click to expand...
My local engine rebuilder(well known rebuilder) told me that even Mobil 1 doesn't have enough Zinc for a flat tappet engine so I add Lucas Zinc to be on the safe side.
 
fordor41 said:
My local engine rebuilder(well known rebuilder) told me that even Mobil 1 doesn't have enough Zinc for a flat tappet engine so I add Lucas Zinc to be on the safe side.
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That is true for high valve spring loads, but flatheads do not use high spring pressure. Zinc is really not needed in a flathead but doesn't normally hurt anything. BUT, don't want to over do it, to much additive is damaging to the engine metal.
 
fordor41 said:
My local engine rebuilder(well known rebuilder) told me that even Mobil 1 doesn't have enough Zinc for a flat tappet engine so I add Lucas Zinc to be on the safe side.
Click to expand...
According to the latest information I have, Mobil-1 15W50 has 1300 ppm Zinc. (Their 10W30 has 900).
 
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