Any truth to this?

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Nov 16, 2002
I asked mobil what the NOAK was for 5w-30. Amsoil tested it as 9.7%. This was the response I got from them.


Thanks for your request. The NOACK volatility is currently typically 12.9%
for Mobil 1 5W-30. An engine oil's performance is based on a variety of
physical and chemical properties and performance features, including low
temperature cranking and pumping viscosity, high temperature high shear
viscosity, fuel economy, catalytic converter protection, etc., which all
must be balanced. For example, altering the product to lower the NOACK
volatility could adversely affect low temperature viscosity and fuel
economy performance. You should use engine oil with the SAE viscosity
grade and quality level as recommended in your vehicle's owner's manual.

Technical Support Engineer

I personally think this is an old trisynthetic number. I also don't believe this guy bc Amsoil has incredible NOAK numbers and great cold weather performance. And no this is not a plug for Amsoil.

I wanted to point out that M1 10w-30 is 6%, 0w-40 is 9%. 12.9% just doesn't fit in. The Mobil NZ site I believe is where I obtained the 0w-40 NOAK.

[ October 24, 2003, 08:29 AM: Message edited by: buster ]

As I recall, the trisynthetic 5w-30 had a Noack of 8.0%, so it was better than the supesyn. I believe the difference was that the trisynthetic used a lower additive treat rate. Part of what evaporates is the additive package and VI modifier.

It is true that if you improve the high temp properties, then the low temp pumpability usually suffers.

Amsoil puts a lot of emphasis on reducing high temp evaporation due to the higher level of ZDDP they use in the formulations.

ZDDP (zinc dialkyl dithiophosphate or zinc diaryl dithiophosphate)widely used as an anti-wear additive in engine oils to protect heavily loaded parts, particularly the valve train mechanisms (such as the camshaft and cam followers) from excessive wear. It is also used as an anti-wear agent in hydraulic fluids and certain other products. ZDDP is also an effective oxidation inhibitor. Oils containing ZDDP should not be used in engines that employ silver alloy bearings. All car manufacturers now recommend the use of dialkyl ZDDP in engine oils for passenger car service.

Amsoil has found a secret use for ZDDP?

I think you misunderstood my response....Amsoil has worked with their additive suppliers - Lubrizol and Ethyl - to develop phosphorus compounds that have very low volatility. The idea is to minimize the amount of P that is burned - this increases the life of oxygen sensors and catalytic convertors.

That's why you'll see that all their oils have very low Noack volatilities. The current specs - all of which have not been posted on their website, are:

0w-30... 8.6%
5w-30... 5.0%
10w-30... 5.5%
Series 3000, 5w-30... 6.5%
10w-40... 6.6%
15w-40... 6.3%
20w-50... 5.9%

New Amsoil spec sheets are first posted in the "dealers only" section of their website, so I see them before the retail customers do ....

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