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Is an Engine Flush Good or Bad?

flushed cylinder head

Should you be concerned using Engine Flush?

To flush or not to flush. (One of our best sellers here in Sioux Falls)

It’s a question whose answer is obvious in the bathroom, but vigorously debated in the garage.

Let’s get right to the point. Is an engine flush good or bad?

Spend a few minutes perusing online forums and you’ll find a range of answers to this question, often involving a 1980s Trans-Am, Camaro or other car that someone thrashed on for years, parked in a pasture for a decade and now wants to revive with an engine flush.

Here’s what we’ll cover:

  • What is an engine flush?
  • How deposits and sludge form
  • Can engine sludge be removed?
  • Is an engine flush necessary?
  • Engine flush as part of maintenance
  • 5 benefits of an engine flush
  • Engine flush products
  • Watch: How to do an engine flush (video)

What is an engine flush?

An engine flush is an aftermarket chemical additive designed to clean accumulated deposits, sludge and other gunk from your engine. You pour it into your engine’s oil-filler port and idle the engine for about 10-15 minutes. It mixes with the oil and circulates through the engine, helping dissolve sludge and clean deposits. Then, you drain the oil (along with much of the gunk, in theory), change the oil filter, add fresh oil and return to the business of driving.

How deposits and sludge form inside an engine

If it did its job, your engine’s performance will return to the heady days of its youth, when it delivered maximum power and efficiency. Over time, however, harmful deposits and sludge may have accumulated, causing power and performance loss.

The tiny openings in the oil pickup tube screen can easily plug with sludge, starving the engine of oil.

Deposits and sludge can form for several reasons, including…

  • Frequent short trips that don’t allow the oil to fully warm up and evaporate moisture
  • Ingestion of air-borne dirt
  • Fuel dilution
  • High heat breaking down the oil

As it settles, sludge can clog narrow oil passages or the screen on the oil pickup tube, restricting oil flow to vital parts, especially the upper valve train. Deposits can cause the rings to stick, reducing engine compression and horsepower.

Can engine sludge be removed?

Yes. The proper detergents in the correct concentration can dissolve engine sludge, deposits and varnish. Ideally, sludge won’t form at all; however, sometimes mechanical issues arise, such as a leaking head gasket, and the formation of sludge occurs. If sludge does form, the oil’s detergents help dissolve and disperse sludge to clean the engine.

This is more challenging than it sounds. For starters, the oil must perform several functions, not just help prevent engine sludge. For that reason, oils contain a limited concentration of detergents (compared to an engine flush product) to ensure room in the formulation for other additives that protect against wear, fight oxidation, combat rust and more.

An engine flush product, on the other hand, is designed solely to clean. AMSOIL Engine and Transmission Flush, for example, contains nothing but potent detergents, making it a more effective cleaner than motor oil. Plus, it cleans at the molecular level, ensuring deposits are dissolved and properly exit the engine with the oil when it’s drained. This is important since some motorists fear that an engine flush will free large chunks and cause an avalanche of debris to clog passages inside the engine. AMSOIL Engine and Transmission Flush guards against this scenario.

Is an engine flush necessary?

A good engine flush can help loosen deposits and dissolve sludge, returning your engine to like-new condition. However, in old engines with high miles, sludge may be the only barrier keeping oil from seeping through worn or cracked seals. Removing the sludge exposes the seals for what they really are – junk. Soon, your engine begins leaking oil, and you’re mind instantly associates the engine flush product with an oil leak.

In reality, the seals were already bad; the flush simply revealed their true condition.

If you suspect your vehicle falls into this camp, leave well enough alone and skip the engine flush. It’s probably not worth trying to revive an engine in such poor condition without first fixing the bad seals or other defects.

In effect, you’re choosing your problem: either sludge and deposits robbing performance or, if you clean the engine, the seals showing their true condition.

An engine flush is part of a good maintenance regimen

But that’s not to say an engine flush is never a good idea. In fact, it’s often the first step in helping restore a neglected vehicle to top-notch performance. And, often when you buy a used vehicle, that’s what you’re getting – a vehicle whose owner found antiquing on Saturday afternoon more enjoyable than changing oil or dropping the transmission pan. Consequently, your “pre-owned” ride, while not complete junk, may boast a sketchy maintenance record.

In these cases, a potent, detergent-based flush can help prepare the engine for new oil, loosening sticky valves or rings and helping remove harmful sludge. While not a required step when switching to AMSOIL synthetic motor oil, we do recommend flushing your engine if you want to give your vehicle a fresh start.

5 benefits of an engine flush

1. Prepares your engine for new oil

An engine flush helps loosen sticky valves or rings and remove harmful sludge and other contaminants. By cleaning the engine prior to installing fresh oil, you ensure the new oil functions as intended and delivers maximum protection. The oil won’t last as long or protect as well if it must contend with sludge and deposits from the previous oil.

By the way, we don’t require use of AMSOIL Engine and Transmission Flush before switching to AMSOIL synthetic motor oil, but we recommend flushing your engine if you want to give it a fresh start.

2. Helps increase fuel efficiency

Contaminants circulating throughout the engine can lead to oil breakdown and increased viscosity – and higher-viscosity oil requires more energy to circulate throughout the engine. Sludge and deposits on engine parts can also increase resistance, which wastes fuel to overcome. Cleaning the engine helps ensure parts move efficiently, maximizing fuel economy.

3. Helps reduce emissions

If deposits in the piston-ring lands cause the rings to stick, oil can migrate into the combustion chamber, where it burns. This not only leads to harmful deposits, it also increases exhaust emissions as the burned oil exits the tailpipe. A good engine flush helps free stuck rings and reduce oil consumption, in turn reducing emissions.

4. Helps reduce heat

Excessive heat is bad for your engine and the oil. Extreme heat reduces engine efficiency while increasing the rate at which the oil oxidizes (chemically breaks down). Sludge and deposits act as insulators that prevent the engine from dissipating heat as designed. Flushing your engine helps ensure it manages heat properly for optimum efficiency and oil life.

5. Convenience

This might not apply to every engine flush, but it applies to AMSOIL Engine and Transmission Flush. It delivers results after just one application. And it only takes 10-15 minutes to use. Plus, you can safely use it in gas or diesel engines and automatic transmissions. While some solvent-based flush products require a cumbersome disposal process, AMSOIL Engine and Transmission Flush uses a detergent-based formulation. As such, you can dispose of it easily with waste oil.

Cylinder head pre-cleanup. Note the sludge around the valve springs and push rod openings.

Post-cleanup with AMSOIL Engine and Transmission Flush, the cylinder head is noticeably cleaner.

Engine Flush Products: I use AMSOIL Engine and Transmission Flush

For the record, I’ve used AMSOIL Engine and Transmission Flush on three different pre-owned vehicles in my time, and it’s worked great. One of them, a 1999 Honda CR-V, accumulated more than 220,000 miles before rust forced me to replace it. Another, an Oldsmobile Intrigue, ran great until a computer problem forced me to trade it off…for the CR-V. The third ran great, but I sold it off after it, too, rusted out.

In sum, flush your engine if you want to give your vehicle a new lease on life. AMSOIL Engine and Transmission Flush, as the name indicates, also works great for cleaning automatic transmissions. Check out this post to determine if a transmission flush or pan drop is better for you. But if you have any reservations about disturbing sludge or deposits that may be holding your old, high-mileage engine together, consider skipping it. It’s up to you.

How to do an engine flush

If you are looking for the best way to flush your engine this weekend, here’s a quick video that will walk you through the process, courtesy of MyJeepStory.

Signature Series Motor Oil Protects Engines From Low-Speed Pre-Ignition

LSPI

SIGNATURE SERIES Protects Engines from Future Industry Problem

LSPI can destroy pistons and connecting rods, bringing an engine to a standstill in seconds. Original equipment manufacturers (OEMs) like General Motors (GM)* have addressed the issue by designing tests to gauge a motor oil’s ability to prevent these destructive events. Signature Series achieved 100 percent protection against LSPI1 in the industry-standard test.

OEMs have been aggressively downsizing engines to meet strict fuel economy and emissions standards while improving power and torque. Most new engines today use some combination of turbochargers, direct-fuel injection and variable valve timing to make more power than their larger counterparts while delivering improved fuel economy.

This scenario seems like all upside for drivers. But today’s smaller, hotter-running engines pose significant challenges to lubricants. The latest is a phenomenon called low-speed pre-ignition (LSPI), also known as “super knock,” which can destroy pistons and connecting rods.

What Is LSPI?

LSPI is another version of engine knock, which has been around since engines were invented. In this case, it occurs under low-speed, high-torque conditions in turbocharged gasoline direct-injected engines – like when you’re taking off from a stoplight. LSPI is the spontaneous ignition of the fuel/air mixture prior to spark-triggered ignition. This form of pre-ignition is more destructive than typical engine knock.

No Magic Bullet

Just as your engine relies on a balanced network of components to function, the motor oil needed to protect it requires additives with the right qualities at the right quantities. While adding more of one ingredient or reducing another seems simple enough, small composition changes can have big impacts. We were determined to find a solution to the LSPI problem without sacrificing the performance of Signature Series in any way.

GM LSPI Test

OEMs like GM have addressed the issue by designing tests to determine a motor oil’s ability to prevent LSPI. The GM LSPI Test records the number of peak pressure events during high-load operation in a turbocharged engine over a five-hour period. Passing the test is required to meet the GM dexos1® Gen 2 specification.

Perfect Score

We armed Signature Series with an advanced detergent system that protects against harmful deposits and LSPI. Signature Series Motor Oil achieved 100 percent protection against LSPI in the engine test required by the GM dexos1 Gen 2 specifications – zero occurrences were recorded throughout five consecutive tests.

API SN PLUS Specifications

API SN PLUS is a recently released specification that was requested by the automobile industry to protect passenger vehicles from LSPI. AMSOIL anticipated this change, and the current formulations of Signature Series, XL and OE synthetic motor oil all meet or exceed the specification. Look for updated product labels featuring the new API “donut” in the near future.

Your customers can be confident that AMSOIL synthetic motor oils protect their modern engines against LSPI, helping their vehicles deliver years of reliable service. For more information on the dangers of LSPI, visit www.amsoil.com/lspi.

 

Example of piston damage due to an LSPI event observed during the testing of a competitor’s motor oil. The red arrows indicate sections of the ring land that have broken away from the piston.

Achieved 100% Protection Against LSPI1

The New SEVERE GEAR Easy-Pack Makes Changing Gear Oil Easy

75W-140 Easy Pack GL5 differential oil bag

The New SEVERE GEAR Easy-Pack Makes Changing Gear Oil Easy

Changing gear oil in differentials and manual transmissions is critical for smooth operatation and reduced maintenance. But professional mechanics and DIY enthusiasts agree: changing gear oil is a hassle.

The rigid conical bottle has been the industry standard for gear lube for decades.

That ’70s squeeze bottle

The source of the hassle can be found in the packaging. For more than 40 years the packaging standard has been a semi-rigid squeeze bottle with a narrow spout. This design was adequate when it was introduced due to the generous clearances and easy access to the differential and other components under your vehicle.

Vehicles, however, have grown more complex. The spaces to access components, including differentials, have shrunk. Trying to fit a rigid bottle into a confined space to reach a small fill hole is a recipe for bloody knuckles. Attempting to squeeze the fluid from the bottle into the differential is a mess, with much of the fluid ending up on you or your garage floor.

Despite these challenges, gear oil is runner-up only to grease for least attention paid among the majority of lubricant manufacturers. For most brands, this lack of focus is likely due to low gear oil sales.

Enthusiast experiences drive innovation

The AMSOIL brand is focused on providing enthusiasts and independent shop owners with the next level in protection. In addition to developing innovative ways to pack more protection into our products, we also focus on packaging innovations.

Many who work at AMSOIL are enthusiasts or DIYers. In fact, a weekend attempt to change gear oil in his truck led our gear-oil product engineer on a search for a better way to package gear oil. The gear-oil pump he had on hand didn’t work. His own attempts to engineer a Rube Goldberg machine of sorts to direct gear lube into the differential didn’t work.

The frustration and hassle led him to a single thought: there has to be a better way.

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

Flexibility eliminates hassle and waste

The result of this effort is the new AMSOIL SEVERE GEAR® easy-pack. The flexible package bends around obstacles so you can easily reach fill holes. This flexibility also allows you to squeeze all of the gear lube into the differential. That way you don’t have to buy extra gear lube just to account for the waste inherent to rigid bottles.

The industrial-strength packaging allows the easy-pack to withstand drops, abrasions and extreme pressure, as shown in the video below. The result is packaging that saves professional mechanics and enthusiast’s time, money, hassle and mess.

BUY THE SEVERE GEAR EASY-PACK NOW

Safetey changing oil at 3,000 Mile? Why not 50 or 100 miles?

Safetey changing oil at 3,000 Mile? Why not 50 or 100 miles?

Busting the 3,000 Mile Oil Change Myth

Changing your oil every 3,000 miles is a practice passed down for generations. The origin likely stems from the noble effort to provide consumers with a simple vehicle-maintenance rule that left plenty of room for error.

Marketed by fast lubes

Fast lube chains, which first entered the market in the 1970s, adopted and amplified the message through sustained marketing campaigns. Owned by major oil manufacturers, fast lube chains had a financial interest in seeing customers frequently and selling more oil, the vast majority of which was conventional.

Endorsed by your dad and mechanic

While this timeline helps provide context, it does little to address the emotional connection to changing oil every 3,000 miles. The reason so many motorists dutifully change oil every 3,000 miles is because their fathers and their mechanics – two of the most influential groups in automotive circles – told them they should. For many people, the 3,000-mile oil change is a tradition that ties them to the person who taught them many important life lessons, like how to keep your car running properly.

Tradition updated with new technology

Many families pass down traditions, and while the spirit of the tradition is upheld, many elements are updated to reflect current technology and lifestyles. Your call to a distant relative during the holidays may now require Skype instead of a rotary phone. Likewise, your annual family vacation may start at the airport instead of in the family station wagon. In the case of the 3,000-mile oil change, we can preserve the noble spirit of taking good care of our vehicles by establishing a habit of changing oil periodically, but not necessarily every 3,000 miles.

Since the advent of the 3,000-mile oil change, advances in lubrication and automotive technology have rendered it outdated, like adding water to automotive batteries, replacing ignition points and adjusting the carburetor. Now, many vehicle manufacturers recommend changing oil every 5,000 miles or longer, with BMW calling for 15,000 miles between oil changes.

Synthetic motor oil technology

Synthetic lubrication technology plays a significant role in moving beyond the 3,000-mile oil change interval. Synthetic motor oil offers better wear protection, improved resistance to temperature extremes and increased cleanliness properties compared to conventional oils. For that reason, it’s safe to use them longer than 3,000 miles.

AMSOIL products provide confidence with additional protection that goes beyond the standard. It’s what your dad or grandfather may have called the “belt and suspenders” approach. For example, AMSOIL Signature Series Synthetic Motor Oil…

  • Provides 75% more engine protection against horsepower loss and wear than required by a leading industry standard.¹
  • Achieved 72% better protection than required by a leading industry standard2, providing ultimate protection against extreme heat and the harmful deposits that can plague turbochargers.
  • Achieved 100% protection against LSPI.3

So, while it’s vital to change your oil and take care of your vehicle, it’s also important to advance your methods in lockstep with the latest technology. And modern synthetic oils have made the 3,000-mile oil change as dated as the rotary phone.

FIND AMSOIL PRODUCTS FOR MY VEHICLE

1Based on independent testing in the ASTM D6891 test using 0W-20 as worst-case representation.
2Based on independent testing of AMSOIL Signature Series 5W-30 in the GM turbo coking test.
3Based on independent testing of AMSOIL Signature Series 5w-30 motor oil in the LSPI engine test as required for the GM dexos 1® Gen 2 specification.

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.