Do we really need a flush?
07-13-2009, 12:36 PM
#1
5th Gear Member
Thread Starter
Join Date: Nov 2008
Location: austin,TX
Posts: 2,084
Do we really need a flush?
http://autotechrepair.suite101.com/article.cfm/040206
A New "Recommended" Maintenance Item...
In the last few years you were probably asked, or told, by you dealer or quick lube place that you need an engine or transmission flush, because the engine oil or transmission fluid is very dirty. They will tell you that it is recommended that you have it done because your engine or transmission will last longer if it is flushed clean. In that they are correct, a clean engine and transmission will last longer. But is flushing the best way to get a dirty engine clean?
What Is An Engine Or Transmission Flush?
Flushing is the high pressure forcing of fluid back against the normal flow of the fluid. In other words if the normal flow is left to right, the flush would force the fluid right to left. This is accomplished by connecting a machine that will force special solvents back through the engine and transmission. The idea is that by forcing cleaning solvents backwards through the system, it will get all the junk and garbage that has formed over time and "flush" it out of the system. In theory this may be sound, but in actual practice, it's dangerous.
The Dangers Of Flushing...
Flush machines do what they say; they force high pressure cleaning solvents back through the engine and transmission and clean out some of the accumulated junk that has formed. Now engines have small passages and galleries through which oil or automatic transmission fluid flow and there are one-way valves that keep the fluids from backtracking for whatever reason. By using an aggressive cleaning procedure like flushing, large chunks of accumulated sludge are broken off and forced backwards through these galleries and valves and, more often than not, lodge tightly and block them. This cuts off the normal flow of the fluid and causes lack of lubrication in an engine and abnormal or no shifting in a transmission. The results are expensive repairs, or more often, engine or transmission replacement.
Who Recommends Flushing As Maintenance?
The shops that want to sell you the engine or transmission flush charge anywhere from $49.95 to $99.95, not including a new engine or transmission. Those are extra. And they state quite emphatically that it is recommended that it be done. But who actually recommends that it be done? I checked with GM, Ford, Chrysler, Nissan, Honda and several other new car manufacturers and not one recommended an engine or transmission flush as routine maintenance. In fact, they specifically don't recommend it at all!! The new car dealerships that do sell them use the implication that since they are the dealer that it must be the factory that recommends it. And if they do say the factory recommends it, they are flat out lying to you.
The only ones who do recommend flushing as a maintenance procedure are the companies that sell the flush machines and the shops that buy them. The flush machine manufacturers state quite clearly in their operating manuals not to use their machines on "high-mileage vehicles". That simple statement proves that flushing is not a safe procedure. It also absolves them of any responsibility of any damage that may occur due to the use of their equipment. This leaves the shop wholly responsible for anything that happens and the cost of correcting the damage that occurs.
I know this since I recently appeared as a witness in a lawsuit where a person was sold an engine flush that destroyed his engine.
The Facts...
The fact is, if you do frequent engine oil and filter changes and service the transmission every 15,000 miles there is no need for a flush. I have customers that change their oil every 3,000 miles and they don't need to use fancy oils and filters, and after over 100,000 miles, the oil comes out almost as clean as it goes in. They have regular transmission services and their transmission still shifts like new, even with well over 100,000 miles on it.
If you have neglected regular oil changes and you want to do some interior engine cleaning, get the oil and filter changed and replace one quart of motor oil for one quart of transmission fluid. The transmission fluid has a high detergent content that will clean the engine without damaging it. Do this every 3,000 miles and you will clean the inside of the engine slowly and gently.
If you do get a flush, I recommend you do it when you can afford to replace the engine or transmission.
A New "Recommended" Maintenance Item...
In the last few years you were probably asked, or told, by you dealer or quick lube place that you need an engine or transmission flush, because the engine oil or transmission fluid is very dirty. They will tell you that it is recommended that you have it done because your engine or transmission will last longer if it is flushed clean. In that they are correct, a clean engine and transmission will last longer. But is flushing the best way to get a dirty engine clean?
What Is An Engine Or Transmission Flush?
Flushing is the high pressure forcing of fluid back against the normal flow of the fluid. In other words if the normal flow is left to right, the flush would force the fluid right to left. This is accomplished by connecting a machine that will force special solvents back through the engine and transmission. The idea is that by forcing cleaning solvents backwards through the system, it will get all the junk and garbage that has formed over time and "flush" it out of the system. In theory this may be sound, but in actual practice, it's dangerous.
The Dangers Of Flushing...
Flush machines do what they say; they force high pressure cleaning solvents back through the engine and transmission and clean out some of the accumulated junk that has formed. Now engines have small passages and galleries through which oil or automatic transmission fluid flow and there are one-way valves that keep the fluids from backtracking for whatever reason. By using an aggressive cleaning procedure like flushing, large chunks of accumulated sludge are broken off and forced backwards through these galleries and valves and, more often than not, lodge tightly and block them. This cuts off the normal flow of the fluid and causes lack of lubrication in an engine and abnormal or no shifting in a transmission. The results are expensive repairs, or more often, engine or transmission replacement.
Who Recommends Flushing As Maintenance?
The shops that want to sell you the engine or transmission flush charge anywhere from $49.95 to $99.95, not including a new engine or transmission. Those are extra. And they state quite emphatically that it is recommended that it be done. But who actually recommends that it be done? I checked with GM, Ford, Chrysler, Nissan, Honda and several other new car manufacturers and not one recommended an engine or transmission flush as routine maintenance. In fact, they specifically don't recommend it at all!! The new car dealerships that do sell them use the implication that since they are the dealer that it must be the factory that recommends it. And if they do say the factory recommends it, they are flat out lying to you.
The only ones who do recommend flushing as a maintenance procedure are the companies that sell the flush machines and the shops that buy them. The flush machine manufacturers state quite clearly in their operating manuals not to use their machines on "high-mileage vehicles". That simple statement proves that flushing is not a safe procedure. It also absolves them of any responsibility of any damage that may occur due to the use of their equipment. This leaves the shop wholly responsible for anything that happens and the cost of correcting the damage that occurs.
I know this since I recently appeared as a witness in a lawsuit where a person was sold an engine flush that destroyed his engine.
The Facts...
The fact is, if you do frequent engine oil and filter changes and service the transmission every 15,000 miles there is no need for a flush. I have customers that change their oil every 3,000 miles and they don't need to use fancy oils and filters, and after over 100,000 miles, the oil comes out almost as clean as it goes in. They have regular transmission services and their transmission still shifts like new, even with well over 100,000 miles on it.
If you have neglected regular oil changes and you want to do some interior engine cleaning, get the oil and filter changed and replace one quart of motor oil for one quart of transmission fluid. The transmission fluid has a high detergent content that will clean the engine without damaging it. Do this every 3,000 miles and you will clean the inside of the engine slowly and gently.
If you do get a flush, I recommend you do it when you can afford to replace the engine or transmission.
07-13-2009, 03:35 PM
#2
1st Gear Member
Join Date: Jun 2009
Location: Illinois
Posts: 83
Great writeup!
This was a big help and appreciate the tip about putting a quart of tranny fluid in with the oil. Is there something you can recommend for the tranny? Last month when i had the car serviced the tech showed me how dirty the tranny oil was and recommended a flush. Good thing I read this before taking it back.
thanks.
This was a big help and appreciate the tip about putting a quart of tranny fluid in with the oil. Is there something you can recommend for the tranny? Last month when i had the car serviced the tech showed me how dirty the tranny oil was and recommended a flush. Good thing I read this before taking it back.
thanks.
07-13-2009, 06:38 PM
#3
3rd Gear Member
Join Date: Jun 2006
Posts: 835
well i dont know about where you guys get your cars serviced but i know at the dealership i work at the tranny flush machine hooks in between the tranny cooler and the line that is connected to the exit side of the tranny cooler and while the car is running it takes in all of the dirty fluid and replaces it with the new clean fluid
and as for engine flushes we use them with our 15k and 30k services and this is just a motor flush that you pour into the motor before you change the oil and let if run for a few minutes and then you do your oil change
and as for engine flushes we use them with our 15k and 30k services and this is just a motor flush that you pour into the motor before you change the oil and let if run for a few minutes and then you do your oil change
07-19-2009, 03:41 PM
#4
3rd Gear Member
Join Date: Dec 2003
Location:
Posts: 518
ya that how both of the flushes were at the place i worked jus a fluid change and a pour in and run engine cleaner i have read that there is no need to buy the engine flush stuff if the oil changes are done at the correct intervals so i dont worry bout it
07-19-2009, 10:34 PM
#6
3rd Gear Member
Join Date: Apr 2008
Location:
Posts: 675
Great writeup!
This was a big help and appreciate the tip about putting a quart of tranny fluid in with the oil. Is there something you can recommend for the tranny? Last month when i had the car serviced the tech showed me how dirty the tranny oil was and recommended a flush. Good thing I read this before taking it back.
thanks.
This was a big help and appreciate the tip about putting a quart of tranny fluid in with the oil. Is there something you can recommend for the tranny? Last month when i had the car serviced the tech showed me how dirty the tranny oil was and recommended a flush. Good thing I read this before taking it back.
thanks.
could have just been dirty due to having 30k + miles on it.
07-21-2009, 06:24 PM
#7
1st Gear Member
Join Date: Jun 2009
Location: Illinois
Posts: 83
I bought the car with 140,000 on it for pretty cheap. I do not know when the fluid was changed last to be honest. Was thinking of doing this in the next 3,000 miles on my next oil change
07-21-2009, 07:56 PM
#8
3rd Gear Member
Join Date: Apr 2008
Location:
Posts: 675
personally, since it has 140k and you dont know if its ever been changed, i would just change the oil/filter/gasket and run it for another 5-10k miles and then change it again.
that 2nd change the oil should look a little more clean. plus the filter/gasket will only run ya $20 plus $20 in trans fliuid.
i would say its most likely just dirty from never/rarely being changed and the tech was tryin to sell you another service for him to make some $$.
i should probably change it on my monte carlo again. bought it with 57k and only changed it once :S
that 2nd change the oil should look a little more clean. plus the filter/gasket will only run ya $20 plus $20 in trans fliuid.
i would say its most likely just dirty from never/rarely being changed and the tech was tryin to sell you another service for him to make some $$.
i should probably change it on my monte carlo again. bought it with 57k and only changed it once :S
08-26-2009, 01:07 PM
#10
3rd Gear Member
Join Date: Nov 2006
Location: Kansas City
Posts: 960
As a shop owner, I take alot of interest in items like this. "Transmission service" and "transmission flush" refer to the same thing. Unless "service" is meant by some to include changing only the filter and replacing whatever fluid comes out when the pan is removed. This only removes about 4 qts of a 10qt system. Transmission flush machines are hooked up as Mustang boy already described. I know MY machine is the same way. No reverse flow here, AND the only pressure is what the transmission itself makes. The machine does not add extra pressure. As far as high mileage is concerned, if a car comes here with mileage north of 100,000mi, I refuse to do that service if asked to. The things that can happen are described in the original post. My opinion is, the original post isn't quite telling the whole story. It's a mix. Most machines dont work as described, and, if transmission "service" isnt done for 100,000mi, then it shouldnt be done at all. It's a damned if you do, and damned if you dont situation. If you do service the transmission, the fresh fluid is likely to break the 'sludge' free (because it has a high detergent content), plug up the filter and ruin the transmission within a month. If you dont service it, it will last longer. How long is an unknown amount.
So, it comes down to preventative maintenence. People change their engine oil more frequent than necessary. Why? It's cheap insurance. My Caravan has 102,000mi. I've "serviced" (flushed) the transmission twice so far. I know it'll last a long time because of it. It's cheap insurance. Mustang only has 17,000mi so far, so nothing has been done except oil changes. Comments are made about shops recommending transmission services for extra profits, when the same could be said about car manufacturers saying dont change the fluid, ever (yes, some do say that). They want to sell another car. If someone has to replace a transmission on something with over 100,000 miles, are they going to consider putting that same money into a new car instead? You bet.
If people took care of their cars like most on this forum take care of their Mustangs, cars could be on the road even longer, therefore, cheaper on everyones wallet. It's ALMOST ALWAYS cheaper to fix it than buying a new car.
So, it comes down to preventative maintenence. People change their engine oil more frequent than necessary. Why? It's cheap insurance. My Caravan has 102,000mi. I've "serviced" (flushed) the transmission twice so far. I know it'll last a long time because of it. It's cheap insurance. Mustang only has 17,000mi so far, so nothing has been done except oil changes. Comments are made about shops recommending transmission services for extra profits, when the same could be said about car manufacturers saying dont change the fluid, ever (yes, some do say that). They want to sell another car. If someone has to replace a transmission on something with over 100,000 miles, are they going to consider putting that same money into a new car instead? You bet.
If people took care of their cars like most on this forum take care of their Mustangs, cars could be on the road even longer, therefore, cheaper on everyones wallet. It's ALMOST ALWAYS cheaper to fix it than buying a new car.
Last edited by SCCAGT; 08-28-2009 at 09:36 AM.
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