Surfing the internet on using synthetic oil in my 1983 300SD and found this. Is this the best choice?
They Say Nothing Outperforms Mobil 1? Wrong!

We now have the independent lab test data for the new Mobil SuperSyn vs. Amsoil. The SuperSyn does not compare to AMSOIL's extended drain interval 25,000 mile/1-year oil or 35,000 mile/1-year oil (0W-30). The test data is as follows for AMSOIL 5W-30 vs. Mobil SuperSyn 5W-30:

NOACK Volatility: AMSOIL: 4.90%, SuperSyn: 9.17%

Flash Point: AMSOIL: 446 deg. F., SuperSyn: 435 deg. F.

Fire Point: AMSOIL: 471 deg. F., SuperSyn: 455 deg. F.

Pour Point: AMSOIL: - 60 deg. F, SuperSyn: -54 deg. F

4-Ball Wear Test: AMSOIL 0.40 mm, SuperSyn: 0.60 mm

TBN (Total Base No.): AMSOIL 12.35, SuperSyn 8.45

Mobil will not recommend or guarantee 25,000 mile/1-year drain intervals like AMSOIL 5W-30, 10W-30 or 10W-40 or 35,000 mile/1-year drain intervals like AMSOIL 0W-30 Severe Service Synthetic does and that is a fact. No-where on the Mobil bottle does it state 25,000 miles/1-year or 35,000 miles/1-year.

Mobil 1 has run the tag line for their advertising stating "nothing outperforms Mobil 1". Mobil makes a good oil, but I'm here to tell you that it does not outperform Amsoil Synthetic Oils. They can come out with all the catchy advertising buzz words to market their oils, but in the final analysis, buzz words don't add one thing to their product's performance. The only reason Amsoil has continued to grow and prosper competing with large corporations like Mobil is that AMSOIL products have consistently performed better.

Here's a special excerpt from A.J. Amaturio, President of AMSOIL, as written in the monthly AMSOIL Action News magazine to all AMSOIL Dealers regarding AMSOIL and Mobil 1:

"As most of you are aware. Mobil 1was introduced after AMSOIL had paved the way for synthetic motor oils back in the '70's. When it was introduced it cased great concern among many of our Dealers. But in my Presidents Message at the time, I assured everyone that having Mobil 1 on the market would only help us sell more oil. Mobil confirmed everything we had been saying about synthetic oils, and our products and claims instantly became more credible.

Since then, we have always been compared to Mobil 1. When people think of synthetic motor oil, they think of Amsoil and Mobil 1, not the other Johnny-come-lately's that have come on the market more recently. I have always said that Mobil 1 is a good motor oil, because compared to the run-of-the-mill motor oils on the market, it is. I have also always said that AMSOIL motor oil is better, again, because it is. Mobil makes their oils to run at normal drain intervals while we make ours for extended drain intervals, and therein lies the difference. Their oils don't have to be as good as ours, so they are not.

To prove that point, we ran a number of comparative tests on our 5W-30 and Mobil 1 SuperSyn 5W-30. The test results are published in this Action News, and they confirm what I have been saying all along. AMSOIL makes a better motor oil.

These test results show significant differences between the oils. Look at the results of the NOACK Volatility Test. Which synthetic oil is going to last longer in service? Look at the difference in Total Base Numbers. Again, which oil is going to provide the longest lasting protection? Look at the Four Ball Wear Test. Which oil will protect against engine wear better? In every category we tested, Amsoil proved superior. Lower pour point, higher flash and fire points, AMSOIL tested best.

So when I hear claims that nothing outperforms Mobil 1, I have to say "wrong!". They may have good slogans and marketing hype, but when it comes to superior performance, I say nothing beats AMSOIL!"

Here is a description of the test parameters discussed in this document:

NOACK Volatility: The NOACK Volatility Test determines the evaporative loss of lubricants in high-temperature service. The more motor oils vaporize, the thicker and heavier they become, contributing to poor circulation, reduced fuel economy, increased oil consumption and excessive wear and emissions. A maximum of 15% evaporation loss is allowable to meet the API SL and ILSAC GF-3 specifications. AMSOIL 5W-30 Synthetic Motor Oil lost an extremely low 4.9% of its original weight during high-temperature service, maintaining its superior protective and performance qualities, while Mobil 1 SuperSyn 5W-30 Motor Oil lost 9.17% of its original weight.

Four Ball Wear: The Four Ball Wear Test determines the wear protection properties of a lubricant by measuring the wear scars produced by four metal balls in sliding contact under the test parameters. The smaller the average wear scar, the better the wear protection provided by the lubricant. AMSOIL 5W-30 Synthetic Motor Oil completed the Four Ball Wear Test producing a smaller wear scar than the Mobil 1 SuperSyn 5W-30 Motor Oil.

Flash/Fire Point: The Flash/Fire Point Test determines the lowest temperatures at which application of a flame will cause lubricant vapors to ignite (flash point) and sustain burning for five seconds (fire point). Lubricants with higher flash and fire points exhibit more stable volatility characteristics and are safer to use and transport. AMSOIL 5W-30 Synthetic Motor Oil has higher flash and fire points than does Mobil 1 SuperSyn 5W-30 Motor Oil.

Pour Point: The Pour Point Test determines the lowest point at which a lubricant flows. The lower a lubricants pour point, the better protection it provides in low-temperature service. As shown in the graph, AMSOIL 5W-30 Synthetic Motor Oil has a lower pour point than Mobil 1Supersyn 5W-30 Motor Oil.

Total Base Number: Total Base Number (TBN) is the measurement of a lubricants reserve alkalinity. The higher a motor oils TBN, the more effective it is in handling contaminants and reducing the corrosive effects of acids for an extended period of time. AMSOIL 5W-30 Synthetic Motor Oil has a higher TBN than Mobil 1 SuperSyn 5W-30 Motor Oil.


AMSOIL is the undisputed leader in synthetics.............



Since 1972, AMSOIL Synthetics have proven to be the BEST. AMSOIL also engineers and manufactures Super Duty Oil filters which have a 12,500 mile service life as well as specialized filtration systems for commercial and fleet applications in cars and light, medium and heavy trucks which can filter particles down to less than one micron ( a standard full flow oil filter can only filter to 20-25 microns, and at a reduced efficiency) making oil changes virtually unnecessary and virtually eliminating engine wear. These filters have been proven by millions of miles of over-the road trucks, construction equipment and fleet service.

Amsoil saves you time and money.
The only 25,000 mile/one- year and 35,000/one- year motor oil in the world.
Exceeds the most stringent performance specifications of all major U.S. and foreign automotive and truck manufacturers.
Provides up to two-times the wear protection of other motor oils.
Increases the life of your vehicle.
Improves performance, fuel economy and efficiency.
Diesel oil and filtration products designed to deliver 1,000,000 miles for over-the-road trucks before engine overhaul.
Used by many national racing teams, fleets, police departments, construction firms and trucking companies.