Motor Flush - good or bad
oldchevy
02-01-2007, 03:08 PM
Has anyone used the big can of motor flush from the parts store? We have all heard the horror stories about using it on our old trucks and suddenly every old seal that has been stuck shut for years suddenly opens and your engine leaks like a fish net, but most people who say that have never actaully used the product.
I was going to put a can in and drive the truck around for about a 1/2 hour before i do my next change and then drain it out.
Has anyone used this product and had noticeable results either good or bad? Does it really open passages and remove sludge from deep inside the engine, or does it just loosen it up and then hunks of sludge break off after a week or so and jam things up?
Please, no old-wives tales, just real life experience.
please advise.
I was going to put a can in and drive the truck around for about a 1/2 hour before i do my next change and then drain it out.
Has anyone used this product and had noticeable results either good or bad? Does it really open passages and remove sludge from deep inside the engine, or does it just loosen it up and then hunks of sludge break off after a week or so and jam things up?
Please, no old-wives tales, just real life experience.
please advise.
Blue Bowtie
02-02-2007, 11:53 AM
Has anyone used the big can of motor flush from the parts store?
I'm certain someone has used it, or it wouldn't still be taking up valuable retail display space. Then again, people have also used ProLong, TMT, Slick50, Lucas, STP, Bardahl, and all sorts of other treatments and additives until they learned better.
We have all heard the horror stories about using it on our old trucks and suddenly every old seal that has been stuck shut for years suddenly opens and your engine leaks like a fish net, but most people who say that have never actaully used the product.
I have used such products. I'll spare you the long version story, but I had a neglected '68 Mustang with a terrible sludge problem. After using an engine flush to clean it up, and two intermidiate hex shafts (and an oil pump with the second shaft), and a crank kit later, I had learned my lesson. The "quick fix" seldom is a fix at all.
I was going to put a can in and drive the truck around for about a 1/2 hour before i do my next change and then drain it out.
Since most of these "flushes" are typically simply high-solvent, low lubricity compositions, I would strongly advise against driving or placing any kind of load on the engine while the solvents are in the sump. The products typically thin the oil, which will endanger the fluid film strength of the lubricant between metal parts like bearings and rotating members. Add to this the possibility of larger pieces of liberated debris being pumped through the oiling system once the filter is plugged and in bypass, and the risk of damage is higher. Simply running the engine at varying RPM would probably be safer.
Has anyone used this product and had noticeable results either good or bad? Does it really open passages and remove sludge from deep inside the engine, or does it just loosen it up and then hunks of sludge break off after a week or so and jam things up?
"Deep inside the engine" is really NOT the problem. The hottest place in the engine is the heads. That is where sludge is likely to originate and accumulate. If you want to determine the extent of the sludge problem, remove the rocker covers and inspect the heads for sludge accumulation. Remove all you can by mechanical means, and plug the drain/return holes to keep pieces out of the sump. A shop vacuum will help in this.
The second most likely place for accumulation is the lifter valley. Since intake removal is more of a chore, you may want to forego that and simply clean the heads as best you can, then allow the oil to do its job and clean away what's left in the rest of the engine.
Accumulations of sludge occurs for several reasons, and most often a combination of the reasons is why sludge happens.
Atmopheric Contamination
A gasoline engine will normally get most of its particulate contamination from atmosphereic dust being drawn into the engine with intake air. A good air filter is important in reducing this dust to a minimum. The filter in the lubrication system is designed to capture the majority of the dust which is ingested in this manner, and trap it until the filter is replaced.
Atmospheric moisture present in the combustion cycle and in the crankcase will react with combustion gasses to form acids. The PCV system is designed to remove MOST of this crankcase contamination by forcibly ventillating the crankcase, removing combustion gasses, moisture, and oil vapors amd burning them through the combustion cycle. This is why it is imperative to have a properly functioning PCV system.
Some of this contamination cannot be removed, and becomes either a dissolved or emulsified part of the oil itself. This is usually effective up to the expected life of the oil. After a certain number of operating hours or mileage, the contamination of the oil will have reached a point where the lubrication properties of the oil are compromised, and the oil must be drained. Neglecting to drain oil after it has reached this point will needlessly cause more wear and damage to the engine.
Wear & Operation
A smaller amount of contamination is a result of metallic surfaces wearing. This is also expected, and the oil filter is designed to control and trap that as well. If you use a lubricant which nearly eliminates friction and wear, oil contamination from wear particles will be similarly eliminated.
An even smaller amount of contamination is from combustion byproducts. Carbon and small amounts of other particulates (usually from fuel additives) are also trapped by the oil filter. This is why it is important to change the oil filter at specified intervals. It is also imperative to maintain the engine in the best possible state of tune to reduce the formation of these particles in the first place. A cleaner running engine will contaminate the oil very little from combustion particles.
Oil Degradation
Additional sources of contamination are due to how atmospheric moisture reacts with the oil, and the degradation of the oil itself. Mineral oils do not have all the properties necessary to adequately protect a gasoline engine under all operating conditions. Because of this, additives are blended into the oil to fortify it. Additives which neutralize acid formation, entrap moisture, suspend particles until they can be removed by the filter, and provide extreme pressure lubrication are commonly blended into all engine oils.
Multi-viscosity oils get other additives which act to fortify the oil's film strength at higher oiperating temperatures. These additives are typically polymers which change their physical molecular properties at changing temperatures. When cold, the molecules contract and curl, taking up less physical space and allowing the liquid into which they are blended to be more fluid (less viscous). When heated, they expand and uncoil, making themselves longer, and overlapping each other to fill the gaps between the other liquid molecules. This effectively makes the overall liquid "soup" to be less fluid, or more viscous. That is how multi-viscosity mineral oils funtion.
Unfortunately, these polymers also burn at elevated temperatures, creating ash, soot, and sludge. Since the molecules are necessarily small to allow them to flow with the oil through the filter and system, the burned molecules are also too small to be trapped by the filter. They continue to flow through the system with the oil until they either settle out as sludge or are drained with the used oil.
Even worse, the amount of polymer added varies. Low grade mineral oil base stocks require more polymer to maintain viscosity at higher temperatures. Multi-viscosiry oils with a wider viscosity rating range also require more polymers. For example, a "10W30" oil has a viscosity range of 20 basis points. A "5W30" oil has a viscosity range of 25 basis points. That means the "5W30" rated oil has more polymers. Moreover, the "10W30" uses a 10W viscosity base stock and enough polymer to maintain viscosity like a 30W at higher temperatures. A "5W30" uses a 5W base stock, and needs more polymer to maintain the viscosity of a 30W at higher temperatures. And the increased amount polymer is not just the 25% that might appear to be the case simply by the numbers, but more like 40% more to do the same thing. More polymer usually means more eventual sludge unless the oil is drained regularly.
Summary
Therefore, the oil used, the operating conditions, and the service intervals will greatly affect the amount of sludge formation. Rather than use a flush to clean up after the miniature disaster which has been happening in the engine for a long time, change one of the variables and allow the oil to clean up the contamination as it is supposed to. You can change the oil you use, change the filter type, change your driving habits or the operating conditions, or change the intervals.
I'm certain someone has used it, or it wouldn't still be taking up valuable retail display space. Then again, people have also used ProLong, TMT, Slick50, Lucas, STP, Bardahl, and all sorts of other treatments and additives until they learned better.
We have all heard the horror stories about using it on our old trucks and suddenly every old seal that has been stuck shut for years suddenly opens and your engine leaks like a fish net, but most people who say that have never actaully used the product.
I have used such products. I'll spare you the long version story, but I had a neglected '68 Mustang with a terrible sludge problem. After using an engine flush to clean it up, and two intermidiate hex shafts (and an oil pump with the second shaft), and a crank kit later, I had learned my lesson. The "quick fix" seldom is a fix at all.
I was going to put a can in and drive the truck around for about a 1/2 hour before i do my next change and then drain it out.
Since most of these "flushes" are typically simply high-solvent, low lubricity compositions, I would strongly advise against driving or placing any kind of load on the engine while the solvents are in the sump. The products typically thin the oil, which will endanger the fluid film strength of the lubricant between metal parts like bearings and rotating members. Add to this the possibility of larger pieces of liberated debris being pumped through the oiling system once the filter is plugged and in bypass, and the risk of damage is higher. Simply running the engine at varying RPM would probably be safer.
Has anyone used this product and had noticeable results either good or bad? Does it really open passages and remove sludge from deep inside the engine, or does it just loosen it up and then hunks of sludge break off after a week or so and jam things up?
"Deep inside the engine" is really NOT the problem. The hottest place in the engine is the heads. That is where sludge is likely to originate and accumulate. If you want to determine the extent of the sludge problem, remove the rocker covers and inspect the heads for sludge accumulation. Remove all you can by mechanical means, and plug the drain/return holes to keep pieces out of the sump. A shop vacuum will help in this.
The second most likely place for accumulation is the lifter valley. Since intake removal is more of a chore, you may want to forego that and simply clean the heads as best you can, then allow the oil to do its job and clean away what's left in the rest of the engine.
Accumulations of sludge occurs for several reasons, and most often a combination of the reasons is why sludge happens.
Atmopheric Contamination
A gasoline engine will normally get most of its particulate contamination from atmosphereic dust being drawn into the engine with intake air. A good air filter is important in reducing this dust to a minimum. The filter in the lubrication system is designed to capture the majority of the dust which is ingested in this manner, and trap it until the filter is replaced.
Atmospheric moisture present in the combustion cycle and in the crankcase will react with combustion gasses to form acids. The PCV system is designed to remove MOST of this crankcase contamination by forcibly ventillating the crankcase, removing combustion gasses, moisture, and oil vapors amd burning them through the combustion cycle. This is why it is imperative to have a properly functioning PCV system.
Some of this contamination cannot be removed, and becomes either a dissolved or emulsified part of the oil itself. This is usually effective up to the expected life of the oil. After a certain number of operating hours or mileage, the contamination of the oil will have reached a point where the lubrication properties of the oil are compromised, and the oil must be drained. Neglecting to drain oil after it has reached this point will needlessly cause more wear and damage to the engine.
Wear & Operation
A smaller amount of contamination is a result of metallic surfaces wearing. This is also expected, and the oil filter is designed to control and trap that as well. If you use a lubricant which nearly eliminates friction and wear, oil contamination from wear particles will be similarly eliminated.
An even smaller amount of contamination is from combustion byproducts. Carbon and small amounts of other particulates (usually from fuel additives) are also trapped by the oil filter. This is why it is important to change the oil filter at specified intervals. It is also imperative to maintain the engine in the best possible state of tune to reduce the formation of these particles in the first place. A cleaner running engine will contaminate the oil very little from combustion particles.
Oil Degradation
Additional sources of contamination are due to how atmospheric moisture reacts with the oil, and the degradation of the oil itself. Mineral oils do not have all the properties necessary to adequately protect a gasoline engine under all operating conditions. Because of this, additives are blended into the oil to fortify it. Additives which neutralize acid formation, entrap moisture, suspend particles until they can be removed by the filter, and provide extreme pressure lubrication are commonly blended into all engine oils.
Multi-viscosity oils get other additives which act to fortify the oil's film strength at higher oiperating temperatures. These additives are typically polymers which change their physical molecular properties at changing temperatures. When cold, the molecules contract and curl, taking up less physical space and allowing the liquid into which they are blended to be more fluid (less viscous). When heated, they expand and uncoil, making themselves longer, and overlapping each other to fill the gaps between the other liquid molecules. This effectively makes the overall liquid "soup" to be less fluid, or more viscous. That is how multi-viscosity mineral oils funtion.
Unfortunately, these polymers also burn at elevated temperatures, creating ash, soot, and sludge. Since the molecules are necessarily small to allow them to flow with the oil through the filter and system, the burned molecules are also too small to be trapped by the filter. They continue to flow through the system with the oil until they either settle out as sludge or are drained with the used oil.
Even worse, the amount of polymer added varies. Low grade mineral oil base stocks require more polymer to maintain viscosity at higher temperatures. Multi-viscosiry oils with a wider viscosity rating range also require more polymers. For example, a "10W30" oil has a viscosity range of 20 basis points. A "5W30" oil has a viscosity range of 25 basis points. That means the "5W30" rated oil has more polymers. Moreover, the "10W30" uses a 10W viscosity base stock and enough polymer to maintain viscosity like a 30W at higher temperatures. A "5W30" uses a 5W base stock, and needs more polymer to maintain the viscosity of a 30W at higher temperatures. And the increased amount polymer is not just the 25% that might appear to be the case simply by the numbers, but more like 40% more to do the same thing. More polymer usually means more eventual sludge unless the oil is drained regularly.
Summary
Therefore, the oil used, the operating conditions, and the service intervals will greatly affect the amount of sludge formation. Rather than use a flush to clean up after the miniature disaster which has been happening in the engine for a long time, change one of the variables and allow the oil to clean up the contamination as it is supposed to. You can change the oil you use, change the filter type, change your driving habits or the operating conditions, or change the intervals.
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