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Why Does Motor Oil Turn Black?

Why Does Motor Oil Turn Black?

Motor Oil Turning Black Isn’t an Indicator of Bad Oil

What causes black motor oil? And when your oil darkens does it mean it’s time to change it? Well, there are a couple of factors that can cause the former. Let’s dig in.

Factors causing black motor oil

Heat cycles naturally darken motor oil

During your drive to work in the morning, your engine reaches normal operating temperature (typically 195ºF-220ºF), heating the motor oil. Then the oil cools while your car sits in the parking lot. During lunch, the oil again is exposed to heat during your drive to Walmart for butter and shoe laces. The process repeats on the way home. And the next day. And the next.

That’s what’s meant by “heat cycles.” The continual exposure to periods of high heat naturally darkens motor oil.

Some additives in motor oil are more susceptible to darkening in the presence of heat than others. In addition, normal oxidation can darken oil, too. Oxidation occurs when oxygen molecules interact with oil molecules and cause chemical breakdown, just like how oxygen causes a cut apple to brown or iron to rust. High heat accelerates oxidation.

Soot causes oil to turn black

While heat cycles cause oil to darken, soot causes oil to turn black. Most people associate soot with diesel engines, but gasoline engines can produce soot as well, particularly modern gasoline-direct-injection engines.

Soot is a byproduct of incomplete combustion. Since soot particles are less than one micron in size, they typically don’t cause engine wear. For comparison, a human hair is roughly 70 microns in diameter.


If soot particles agglomerate into larger wear-causing contaminants, the oil filter will catch them. Sometimes people who use bypass filtration systems, which can filter contaminants down to two microns, express surprise that the motor oil is still black. Soot, however, can still elude filtration down to two microns. Any finer filtration and the filter could catch dissolved additives in the motor oil.

Oil Myth: The color of the oil indicates when it’s time for an oil change

It’s common to assume that black motor oil has worn out or become too saturated with contaminants to protect your engine and requires changing. Not necessarily. As we saw, discoloration is a natural byproduct of heat and soot particles, which are too small to wear out your engine.

The only surefire way to determine if the oil has reached the end of its service life is to perform oil analysis. Chemically analyzing an oil sample reveals the condition of the oil, the presence of contaminants, fuel dilution and so on. Several companies offer oil analysis services, including Oil Analyzers INCWe keep the kits here in Sioux Falls

Absent oil analysis, it’s best to follow the oil-change recommendation given in your vehicle owner’s manual or by the motor oil manufacturer. The recommended service intervals for AMSOIL products, for example, are based on thousands of data points spanning years of use.

It’s best to trust the data, not your eye, in this case. Otherwise, changing the oil could amount to throwing away good oil.

Time for an oil change? Find AMSOIL product for your vehicle here.

Severe Gear®: The Right Tool For The Job

The SEVERE GEAR easy-pack eliminates the hassles of changing gear lube.

Worlds Best Differential Oil – SEVERE GEAR®:

Here in Sioux Falls we have to stock more and more all the time. makes me wish I bought a several pallets back way back when.  But it makes a HUGE difference. Temperature alone!

Your vehicle’s differential is likely not top of mind while hauling snowmobiles or ATVs for a fun weekend on the trails. Unfortunately, towing is in the severe service category and places extreme stress on your drivetrain. Today’s vehicles produce substantially more horsepower, torque and towing capacity than their predecessors, yet the design of differential gears and bearings remains largely unchanged. Many differentials even use less gear lube and lower viscosities than before in an effort to reduce drag and increase fuel economy. In essence, less gear lube is responsible for providing more protection.

Fighting the Grind

Differential designs have inherent weaknesses. In a traditional automotive differential, the pinion gear concentrates intense pressure on the ring gear. As the gear teeth mesh, they slide against one another, separated only by a thin layer of lubricant. The repeated stress the lubricant film bears can shear gear lubes, causing permanent viscosity loss. Once sheared, the fluid film weakens, ruptures and allows metal-to-metal contact, eventually leading to gear and bearing failure. The situation is amplified by severe-service applications like towing.

Thermal Runaway

The extreme pressures and temperatures placed on gear lubricants can lead to a serious issue called thermal runaway. As temperatures in the differential climb, some gear lubes lose viscosity and load-carrying capacity. When extreme loads break the lubricant film, metal-to-metal contact occurs, increasing friction and heat. This increased friction and heat, in turn, results in further viscosity loss, which further increases friction and heat. As heat continues to spiral upward, viscosity continues to spiral downward. Thermal runaway is a vicious cycle that leads to irreparable equipment damage from extreme wear, and ultimately catastrophic gear and bearing failure.

AMSOIL SEVERE GEAR Synthetic Gear Lube

SEVERE GEAR 75W-90, 75W-110 and 75W-140 excels in protecting gears and bearings from the rigors of severe-service operation. By design, it resists breakdown from high heat, preventing acids and carbon/varnish formation. Its wax-free construction also improves cold-flow properties, improving fuel economy and cold-weather performance.

Also available are 190 and 250 weight versions!

• Superior film strength

• Controls thermal runaway

• Protects against rust and corrosion

• Helps reduce operating temperatures

• Maximum efficiency

• Long oil, seal and equipment life

• Flexible easy-pack for clean, fast installation

Stop in here at 47073 98th St just off of the Tea Exit behind Marlins.

AMSOIL Products Target Everything But Your Prey

AMSOIL Products Target Everything But Your Prey

AMSOIL Products Target Everything But Your Prey

Hunting season is fast approaching. Your weapons help you harvest your prey, but your truck, UTV/ATV, trailer and other equipment help you find it. As you’re scouting your hunting area or clearing firing lanes, take some time to prep your vehicles and equipment, too. That way you can focus on hunting this fall, not fixing downed equipment.

“I use this gun oil in everything from my rifles to my everyday carry. Works in extreme heat and freezing temps just fine. High-quality just like all other AMSOIL products.”

Know-it-All’s don’t know it all until they try AMSOIL!

James
Banning, Calif.

FIREARMS

AMSOIL Synthetic Firearm Lubricant

  • Helps prevent blockage, jams and wear
  • Outstanding protection in hot and cold climates

AMSOIL Firearm Cleaner

  • Removes fouling and powder residue
  • Protects against corrosion

 

TRUCK

AMSOIL Signature Series Synthetic Motor Oil

  • 75% more engine protection against horsepower loss and wear than required by a leading industry standard¹, extending the life of vital components like pistons and cams.

AMSOIL Signature Series Max-Duty Synthetic Diesel Oil

  • The top tier of AMSOIL protection and performance for diesel engines. Provides 6X more engine protection.²

AMSOIL SEVERE GEAR® Synthetic Gear Lube

  • New easy-pack eases installation
  • Guards against gear and bearing wear
  • Great for towing and hauling

 

TRAILER

AMSOIL Synthetic Water-Resistant Grease

  • Great for trailer bearings
  • Protects against water washout

 

ATV/UTV

AMSOIL Synthetic ATV/UTV Motor Oil

  • Protection for demanding chores and tough terrain
  • Superior all-weather performance

AMSOIL Synthetic ATV/UTV Transmission and Differential Fluid

  • Reserve protection for heavily loaded gears

AMSOIL Synthetic Front-Drive Fluid

  • Protects high-stress hubs and differentials

 

MISCELLANEOUS

AMSOIL Silicone Spray

  • Spray on your boots to resist water

AMSOIL MP

  • Silences squeaks and lubricates metal surfaces

 

¹Based on independent testing in the ASTM D6891 test using 0W-20 as worst-case representation. ²than required by the Detroit Diesel DD13 Scuffing Test for Specification DFS 93K222 using 5W-30 as worst-case representation.

Signature Series Battles Sludge

Signature Series Battles Sludge

The health of your engine depends on motor oil circulating quickly and efficiently through the system, but sticking components and obstructed passages inhibit motor oil from lubricating, cooling and protecting your engine. Engine “sludge” occurs when oxidized oil and contaminants build up on engine surfaces. It can restrict the flow of oil to the point of engine failure and costly repairs.

Warehouse note: The so called “fully synthetics” which are mostly group III’s or a combination of a majority group II and a fraction III ($3.50 synthetics)  to a majority III and a fraction of IV ($8.50 synthetics) – all based on price and what the stock holders allow to be used for a desired profit.. Note that all of these WILL leave deposits in the form of sludge. Turbocharged engines must avoid these brands which include the silver one shaped like a shampoo bottle. 

Sludge: Where It Starts & How It Ends

  • The valve cover and oil pan are generally the first areas sludge appears.
  • The oil pick-up tube screen is often the next spot it accumulates, impeding oil flow through the system.
  • What begins as a thin film of lacquer or varnish deposits eventually bakes into an expensive mess.

 

The Sequence VG Engine Test

Engine failures due to sludge are often caused by a clogged pick-up tube screen – the motor is effectively starved of oil. The Sequence VG Engine Test determines how well an oil resists sludge formation and keeps the lubricant flowing freely throughout the system. The test is required for API SN PLUS – a specification recommended by most domestic vehicle manufacturers.

TEST PARAMETERS

 

Engine Ford* 4.6L V-8
Duration 216 hours
Measures Sludge and varnish deposits, piston ring sticking, clogged oil pump screens and roller pin wear
Simulates Taxi, delivery or commuter vehicle service
Requirement Oil pick-up tube screen limited to 10 percent blockage

 

The Results

Signature Series Synthetic Motor Oil was subjected to the Sequence VG to measure its ability to prevent sludge. As expected, Signature Series produced an oil pick-up tube screen virtually free from sludge (see image). Our unique combination of detergents and high-quality base oils control oxidation and sludge to keep engines clean and efficient.

 

Signature Series has 50 percent more detergents1 to help keep oil passages clean and promote oil circulation. It provides 90% better protection against sludge2.

Warehouse Note: Thankfully our efforts here in Sioux Falls have made the Signature Series our top seller and on the minds of many who want their investment to remain like new beyond 250,000 miles. People are realizing that it’s not all about change frequency as a non “true synthetic” can cause damage in just 10 miles in GDI engines due to LSPI.. Not to mention why I adopted AMSOIL back in the day – the added power and performance!!

1 vs. AMSOIL OE Motor Oil
2 Based on independent testing of AMSOIL Signature Series 5W-30 in the ASTM D6593 engine test for oil screen plugging as required for the API SN PLUS specification.
*All trademarked names and images are the property of their respective owners and may be registered marks in some countries. No affiliation or endorsement claim, express or implied, is made by their use. All products advertised here are developed by AMSOIL for use in the applications shown.

How Do I Switch from Conventional to Synthetic Oil?

How Do I Switch from Conventional to Synthetic Oil?

How Do I Switch from Conventional to Synthetic Oil?

To borrow a famous slogan, just do it.

There is still some confusion about changing to a different type of oil in vehicles, particularly older models that have accumulated many miles. A small group of ill-informed individuals in garages and on blogs still cling to old beliefs that synthetic motor oils cause roller followers to “slip or skid,” or that switching to synthetic motor oil causes issues in older engines, particularly oil leaks.

Facts have since replaced these outdated ideas about synthetics causing engine problems.

The use of synthetic lubricants is growing rapidly because properly formulated synthetics offer benefits well beyond what conventional and synthetic-blend products provide. Many new passenger car and light truck vehicles come factory filled with synthetic lubricants – not just high-performance sports cars.

There are a couple ways to switch to synthetic motor oil for the first time.

• Jump right in and simply change the oil. Take your vehicle to your mechanic or the nearest quick lube and ask for synthetic motor oil. Or, dust off your drain pan and do it yourself. You don’t have to do anything special to your engine first, and the synthetic oil isn’t going to cause problems in your vehicle that weren’t already there.

• Flush the engine first. Though not required, an engine flush more immediately removes sludge and debris accumulated over time. AND neutralizes acids so the new oil’s detergents can be more aggressive to keeping your engine deposit free.

The main difference between flushing your engine and a normal oil change to synthetics is the rate at which the built-up debris is removed from older engines. If you change to AMSOIL synthetic motor oil without flushing, for example, the detergents in the motor oil will clean accumulated deposits from the engine over subsequent oil changes. When you useAMSOIL Engine and Transmission Flush, the cleanup is more immediate and helps ensure the engine is clean and free of any accumulated contaminants.

Wondering if an engine flush is right for your vehicle? Find out here.

However, we recommend using AMSOIL Engine and Transmission Flush if you want to give your engine a fresh start before switching to synthetic motor oil.

Ready to make the switch to synthetic motor oil? Check out our Product Guide for the right oil for your vehicle.

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