from another forum

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1,025
Location
Albany NY
I have worked as a mechanic for years and have had extensive training when it comes to different types of oils and how they will interact when mixed. I am not expert by any means, but I have done research on the subject, and I do have hands-on experience with the subject. I know you can switch at any time if you want to; however, it is not recommended to go directly from full synthetic to conventional. To do so you must properly flush and clean the engine. Not all, but many synthetic oils will coagulate when mixed with pure conventional oil. Synthetic blended oils are not simply conventional and synthetic mixed as many think. Synthetic blend (also known as half synthetic) has a conventional oil base, but the manufacturers add a variety of detergents and other additives to the conventional oil to give you "the best of both worlds". Depending on application and climate some may benefit from running conventional oil over synthetic, though in most modern automotive engines people will benefit from full synthetic under the right conditions. I did not elaborate more in my above posts as I wanted to keep it simple. A general rule of thumb for internal combustion engines is that you do not go back to conventional oil after you have made the switch to full synthetic. Going from full synthetic to synthetic blend is in most cases ’okay’ without a proper flush, but since the OP had full synthetic in the engine before the previous oil change
 
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13,260
Location
North Carolina
sorry , but i don't agree. There is no evidence of coagulation. All the major oil producers state their oils are all compatable as long as its api rated. I switch back and forth in my oldsmobile all the time. I have run mobil 5000 nextgen maxlife and i just changed it today using napa synthetic. After rereading this, i'm hoping that the OP is quoting a forum and these are not his statements.
 
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9,808
Location
New Jersey
This is not a concern... Many years ago around 1974 or so when synthetic was "real synthetic" i heard that from a couple of people i was young not even close to having my drivers license but i never forgot it but over the years hanging around the families engine shop i realized that 90% of people put in anything that said oil and most had no problems. To this day people go to quick lubes and everywhere else to change their oil and i dont know anyone who had that problem. Everything seems to mix these days im pretty sure there is a rule somewhere that says oils have to be compatible but not 100% sure. Buy whats on sale with the ratings your engine demands
 
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5,091
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USA
Most synthetics are Group III,which is merely highly refined dino oil..totally compatible with regular dino oil.Thank the stupid Feds for allowing oil pumped out of the ground to be considered "synthetic".If you have visions of test tubes and mad scientists "making" synthetic oils from man made materials...think again.
 
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War Eagle
I am going to throw in the [censored] flag on this post. I mean bull [censored], of course. You aint quite right so to speak. This thread should be removed from this forum and deemed useless informaion
 
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18,627
Location
Michigan
I see..quoted from another forum...granted, I would have mentioned that in the first post! For a minute I thought the pitchforks were coming out! shocked2
 
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19,686
Location
Sunny Florida
Mustang Forums is well known for the rowdy atmosphere and the misinformation. What a piece of uninformed nonsense. My only pity is for the poor newbie who reads that and assumes it is the truth...
 
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35,818
Location
NY
Originally Posted By: SteveSRT8
Mustang Forums is well known for the rowdy atmosphere and the misinformation. What a piece of uninformed nonsense. My only pity is for the poor newbie who reads that and assumes it is the truth...
But Steve its the Internet it must be true.
 
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19,686
Location
Sunny Florida
Originally Posted By: demarpaint
Originally Posted By: SteveSRT8
Mustang Forums is well known for the rowdy atmosphere and the misinformation. What a piece of uninformed nonsense. My only pity is for the poor newbie who reads that and assumes it is the truth...
But Steve its the Internet it must be true.
Yep, you are absolutely correct!
 
Messages
961
Location
Ohio
Originally Posted By: ted s
I have worked as a mechanic for years and have had extensive training when it comes to different types of oils and how they will interact when mixed. I am not expert by any means, but I have done research on the subject, and I do have hands-on experience with the subject. I know you can switch at any time if you want to; however, it is not recommended to go directly from full synthetic to conventional. To do so you must properly flush and clean the engine. Not all, but many synthetic oils will coagulate when mixed with pure conventional oil. Synthetic blended oils are not simply conventional and synthetic mixed as many think. Synthetic blend (also known as half synthetic) has a conventional oil base, but the manufacturers add a variety of detergents and other additives to the conventional oil to give you "the best of both worlds". Depending on application and climate some may benefit from running conventional oil over synthetic, though in most modern automotive engines people will benefit from full synthetic under the right conditions. I did not elaborate more in my above posts as I wanted to keep it simple. A general rule of thumb for internal combustion engines is that you do not go back to conventional oil after you have made the switch to full synthetic. Going from full synthetic to synthetic blend is in most cases ’okay’ without a proper flush, but since the OP had full synthetic in the engine before the previous oil change
This mentality is the old school of thinking that still gets perpetuated today among many mechanics, technicians and even fleet managers. I'm not surprised at all that they guy on the mustang forum thinks this way. There are some real errors here though: To do so you must properly flush and clean the engine [FALSE] Although engine flushes are good once in a while (especially if the maintenance history is unknown). There is no need to do so when changing between conventional and synthetic. Not all, but many synthetic oils will coagulate when mixed with pure conventional oil. [FALSE] I haven't heard this one in a long time. With current synthetics being primarily GTL, PAO or other Group III base oils, there is no problem with mixing, changing or otherwise. Synthetic blended oils are not simply conventional and synthetic mixed as many think. Synthetic blend (also known as half synthetic) has a conventional oil base, but the manufacturers add a variety of detergents and other additives to the conventional oil to give you "the best of both worlds". [BOTH TRUE AND FALSE] You can't unilaterally say what is in a synthetic blend because there is no industry standard. There are many common practices, but no standard definition. Manufactures also add a variety of detergents and other additives to synthetic oils, synthetic blends as well as conventional oils. These additives are what does all the work of an oil. The base oil has important functions too, and the additives and the base oil have to work together, but gone are the days where conventional oils are designed with little to no additives (that hasn't been that way for decades). A general rule of thumb for internal combustion engines is that you do not go back to conventional oil after you have made the switch to full synthetic. [FALSE] If this was the 1970's I'd probably say this is an ok rule but in today's oil environment you can switch back and forth without any concern of performance. The history of this tradition has to do with how early PAO based oils affect engine seals. This is no longer a major concern like it once was. The question anyone switching should be asking is why are they switching? If you are looking for the best performance or protection then matching an oil with your needs and application takes time and effort. Why after finding something that works would you switch? OTOH if you are mostly concerned with the cost of your oil change and you are shopping regularly for deals then don't worry about it. These kinds of things get passed on from generation to generation and perpetuate throughout time. Mostly because the general public - including mechanics are woefully instructed on current oil technologies and their applications. Thankfully there are organizations like Noria and sites like BITOG which try to educate and inform consumers. Feel free to take my response and post it on the mustang forum if you like.
 
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