5W-30 motor oil is the top viscosity recommendation by automakers over the past four decades for use in many vehicle types. From passenger cars, SUVs, light vans and trucks to high-performance turbo-charged and supercharged engines. Furthermore, high-mileage 5W-30 motor oil is specially formulated for late model vehicles or newer vehicles with over 75,000 miles/120,000 kilometers. High mileage motor oil, with its unique additives and formulation, helps to reduce oil burn-off, and helps prevent oil leaks that may occur in older engines.
What does 5W-30 mean?
The numbers refer to the weight and thickness, or viscosity, of the oil while the "W" stands for "winter". So it's simply "five-winter-thirty" but we say "five-w-thirty". Motor oil gets thicker when it’s cold and thinner when it heats up. The first number indicates the viscosity of the oil at cold temperatures (usually during winter), and the second number indicates the viscosity at operating temperatures.
The comparison
Today we're putting some of the top selling 5W-30 oil brands head to head to see which SAE 5W-30 motor oil is the best. We're comparing six high mileage 5W-30 synthetic and blended oils that can be used in the many consumer vehicle applications and are some of the best carriers for Bitron's Engine Treatment oil additive.
A while back we compared five 0W-20 synthetic oils suitable for newer and lower mileage vehicles. If you missed that article, and you use a 0W-20 oil, you can read it here.
The six reviewed 5W-30 brands
The six oil brands we're comparing are (in no particular order):
- Valvoline
- Super Tech
- Pennzoil
- Castrol
- Mobil1
- STP
Comparison categories
We're comparing the 5W-30 oils in four key categories:
- Cleaning power
- Anti-corrosion power
- Anti-wear power
- Cost per quart
There are other categories oils can be compared in, such as viscosity, volatility and contamination. However, after our review we've found that they are all exceedingly similar in those other categories and the deciding comparison categories were the above listed four key categories - similar to our 0w-20 comparison.
It's important to note that contamination in all oils reviewed is almost non existent.
Cleaning power
An oil's ability to clean is derived from detergent additives that help to keep metal surfaces in an engine clean by controlling formation of deposits (i.e. sludge, varnishes). These deposits can harm an engine by clogging oil passages that lubricate an engine, increase wear and reduce engine performance. A blend of calcium and magnesium-based detergents are most commonly used. All of the reviewed oils contain calcium, magnesium, sodium and barium in differing amounts in parts per million (ppm).
Anti-corrosion power
Detergent additives, such as calcium and magnesium, also help prevent corrosive wear by neutralizing acids formed during combustion and other processes in an engine. Total Base Number (TBN) is a laboratory test that measures an oil’s ability to neutralize these acids and it is the value we used to determine an oil's anti-corrosion capability.
Anti-wear power
Anti-wear additives help protect metal surfaces against impact friction and wear between moving parts in an engine. These additives work by forming a protective film between moving surfaces. The most widely used anti-wear additives are phosphorus and zinc. Some lubricant manufacturers also employ the use of anti-wear additives containing boron, molybdenum and titanium among others. All of the oils reviewed contain phosphorus, zinc, boron, molybdenum and titanium.
Anti-wear additives are multi-functional in that they also act as corrosion inhibitors and, more significantly, antioxidants helping prevent oil from oxidizing too quickly.
Cost per quart
To compare costs we used regular five quart container online pricing at Walmart in US Dollars and divided by five to arrive at a per quart cost. As engine oils are commoditized consumer products we expect pricing will be similar in other markets (excluding specials and market promotions).
Learn how you can enhance your engine oil
The data
We reviewed the additive amounts, total base numbers and cost per quart to arrive at total values in each category for each synthetic oil.
Then, by taking the above data, we ranked the oils from one to five with five being the best and one being the worst in a given category.
Based on the rating of 1 to 6, where 1 is the best and 6 is worst, we can now see how the oils compare across categories. No single oil wins in multiple categories. Valvoline comes out on top in cleaning capability with second place in anti-corrosion but last in anti-wear capability. Pennzoil seems to be the most well balanced, performing first in anti-wear, second in cleaning and right in the middle when it comes to anti-corrosion and price. Super Tech 5W-30 is by far the most cost effective option while still competing well in anti-wear capability but comes in last in cleaning and anti-corrosion.
It is really important to note that the difference in the rating system can seem significant, however, by looking at the data above all of the oils are fairly similar. You will be hard pressed to notice a difference between them in most day to day applications in a properly maintained vehicle.
Finally, the above ranking assumes we value each category the same. This is not the case, so we arrived at a new ranking in each category by weighing each category by order of importance and totaling the category ranking to arrive at an overall oil ranking. Of course this is subjective and your priorities may be different. However, as the oils are extremely similar across the board, in our view the cost is the most important, followed by anti-wear power, then anti-corrosion power and finally cleaning power.
That gives us a new overall total point rating:
The results
Valvoline is the winner (again) with Mobil1 in second place, STP in third, Quaker State in fourth, Super Tech in fifth and Pennzoil in sixth place.
Learn how you can enhance your engine oil
At the end of the day you cannot go wrong with any of these options. However, if you are planning on using Bitron, or already are, you may choose to give even more value to the most price effective option as Bitron metal treatment technology will take any oil to the next level in terms of anti-wear protection, cleaning and anti-corrosion capability.* We get into this unique ability of Bitron metal treatment technology in our last article "How does Bitron work?". If you have not read that article, be sure to do so.
Send us any questions by emailing us or post your comments below! See you on the road!
*Important: As always, be sure to read and follow your vehicle's maintenance guidelines and recommended schedule.
Read Next: Drag Racing Extreme Performance Oil Additive Results
As you can see, the piston rod bearing housing is completely clean of any deposit build-up. The bearing itself is clean of any scoring or scuffing, has its original thickness and its surface looks highly polished. After 350 runs, all the valve parts and the block are completely clean. Usually without Bitron, they have all their surfaces covered with a thick layer of carbon deposit.
The piston on the left was taken out after only 70 runs out of an engine without Bitron. The piston skirt has severe scuffing. The piston on the right was taken out of an engine after 350 runs with Bitron Engine Treatment. The Bitron treated engine was in operation 5 times longer! The piston has no signs of wear, is completely clean, and all the friction surfaces are polished.
A close-up of an upper end of a piston after 350 runs with Bitron Engine Treatment. Since in dragsters it is prohibited to use any fuel conditioners, only Bitron Engine Treatment was used. As you can see, there is carbon deposit above the upper ring, but none under it and lower. The ring surfaces are polished and clean and the cylinder skirt is completely clean. Because of the polishing effect of Bitron Engine Treatment oil additive, the tighter seal of the piston rings prevented the penetration of combustion gases into the oil system.
Finally, the liner wall of one of the cylinders was also clean after 
Energy that occurs from friction is converted to heat. The heat occurs from billions of collisions from microscopic peaks called asperities (see image) on the surface of moving parts. In regular oil, these asperities immediately break off and become wear particles detectable in oil. Bitron, by contrast, helps prevent this through its film strength and metal bond. The asperities bend, fold and smooth out with Bitron and result in a smoother surface and far fewer breaks so there are fewer wear particles and reduced friction. In addition to that, the localized heat caused by asperity collisions causes normal lubricants to migrate away from the source of friction, but not Bitron. Bitron's positive ionic charge is attracted to the heat and therefore to the source of friction. Therefore, Bitron creates a layer which is continuously replenished and self healing as normal wear occurs. Even better, Bitron's attraction is stronger in extreme operating conditions as there is more heat!