# Switch to Synth?



## YikeGrymon (Sep 12, 2005)

So I searched on a number of things related to this, have found surprisingly little.
I'm thinking of switching from "conventional" oil to synthetic. Car has just about 60K on it, oil has always been changed at good intervals (5K max, or 6 months max for those slow-mileage periods... car has pretty low miles for its age). Now I'm wondering about a few things:
• What's the story with a change to synthetic oil "revealing" or "creating" leaks that weren't there before? And do those leaks sort themselves out after a while?
• Is there a flush procedure I oughta do before making a change like this? Or does the car not care (I imagine after one or two changes with synthetic, it wouldn't matter much)?
• Any brand/weight the preferred one to use? and
• What sort of months/mileage might I go between changes if I switch to synth?
TIA, all.


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## shipo (Jan 3, 2006)

*Re: Switch to Synth? (YikeGrymon)*


_Quote, originally posted by *YikeGrymon* »_• What's the story with a change to synthetic oil "revealing" or "creating" leaks that weren't there before? And do those leaks sort themselves out after a while?

I've never seen any scientific evidence that shows that switching to synthetic oil will cause leaks. Said another way, all evidence I have seen on the subject suggests that the "switching to synthetic oil causes lease" myth is just that, an Old Wives Tale.

_Quote, originally posted by *YikeGrymon* »_• Is there a flush procedure I oughta do before making a change like this? Or does the car not care (I imagine after one or two changes with synthetic, it wouldn't matter much)?

Don't waste your time with a flush, conventional oil and synthetic oils are 100% compatible these days.

_Quote, originally posted by *YikeGrymon* »_• Any brand/weight the preferred one to use? and

A question that often generates lots of controversy. Personally I'd suggest any VW approved 502.00 (or better) synthetic oil, Mobil 1 0W-40, Castrol Syntec 0W-30, Castrol Syntec 5W-40, Valvoline Synpower MST 5W-30, Valvoline Synpower 5W-40, or Valvoline Synpower 20W-50.

_Quote, originally posted by *YikeGrymon* »_• What sort of months/mileage might I go between changes if I switch to synth?

I ran my 1995 VR6 Passat GLX between 7,500 and 10,000 miles on Mobil 1 (various grades), and had a Used Oil Analysis (UOA) performed every two or three oil changes, always with stellar results.


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## YikeGrymon (Sep 12, 2005)

*Re: Switch to Synth? (shipo)*

Great info, shipo. Thanks.
To my first point/question above, I've heard that synthetic "lubricates so much better that it finds its way into small spaces etc that conventional oil can't/won't get into." Which is good. But it also thus passes through spaces that conventional doesn't. And that this is the germ of "leaks that you didn't have previously." I'm not sure I buy this, because it's under pressure, after all (though not a ton of pressure), and so wouldn't any liquid in there have just as much tendency to slip through <wherever>?
Then there's the seal issue I've heard about. Something about seals etc deteriorating because of the change. Not sure I get this at all.
Another thing I don't understand is why I found so *little* on this whole topic upon searching. Unless I was looking for stuff the wrong way....
AND: Where does one go for and/or how does one go about scoring a UOA?


_Modified by YikeGrymon at 8:04 AM 7-28-2008_


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## shipo (Jan 3, 2006)

*Re: Switch to Synth? (YikeGrymon)*


_Quote, originally posted by *YikeGrymon* »_To my first point/question above, I've heard that synthetic "lubricates so much better that it finds its way into small spaces etc that conventional oil can't/won't get into." Which is good. But it also thus passes through spaces that conventional doesn't. And that this is the germ of "leaks that you didn't have previously." I'm not sure I buy this, because it's under pressure, after all (though not a ton of pressure), and so wouldn't any liquid in there have just as much tendency to slip through <wherever>?

Urban legends are very difficult to silence, and this one falls into that catagory if you ask me. As for synthetic oil lubricating better than conventional oil, ummm, with the exception of extreme conditions (i.e. cold weather waaay below zero or a fire breathing turbo application used), I've never seen any scientific evidence that proves that synthetic lubricates better, it simply does what it does a whole lot longer than conventional oil.

_Quote, originally posted by *YikeGrymon* »_Then there's the seal issue I've heard about. Something about seals etc deteriorating because of the change. Not sure I get this at all.

At one point in time (like back in the 1970s), synthetic oils interacted with engine seals in such a way that this was often the case, however, since at least the early 1980s, seal issues became a thing of the past.

_Quote, originally posted by *YikeGrymon* »_AND: Where does one go for and/or how does one go about scoring a UOA?

I use Blackstone Labs: http://www.blackstone-labs.com/


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## YikeGrymon (Sep 12, 2005)

*Re: Switch to Synth? (shipo)*

All righty then.
I'm sold.


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## jakub28 (Jul 27, 2008)

Synthetic oil is the equivalent of an engine rebuild every time you turn the key (ok not quite)..


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## jakub28 (Jul 27, 2008)

I forgot to add, I don't need a block heater in the winter when it is -45 Celcius / -49 Fahrenheit..the engine turns over a bit slower but it starts up easily..that is how little a synthetic oils viscosity varies with temperature.
On conventional oil, there would be fudge popsicles in the sump at that temperature.


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## YikeGrymon (Sep 12, 2005)

*Re: (jakub28)*


_Quote, originally posted by *jakub28* »_I forgot to add, I don't need a block heater in the winter when it is -45 Celcius / -49 Fahrenheit..the engine turns over a bit slower but it starts up easily..that is how little a synthetic oils viscosity varies with temperature.
On conventional oil, there would be fudge popsicles in the sump at that temperature.

.
.
Nice. This by itself is worth the added cost, I'd say....


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## mk2allday (Apr 27, 2007)

synthetic oil molicquiles are half the size or conventinal oil so generally if you have a slight oil leak useing synthetic oil might make it worse due to its detergents and other aditives, yes syntheitic is a very low friction oil , if you have a leaky engine i do not sugest you do an egnine flush because any gunk of the inside of your engine cloging up those leaky spots would become loose and your would leak again i see it happen all the time,you can allways switch on and off between conventinal oil and syntetic oil but not mobile1, mobile1 oil has teflon in it and every time your engine is running their is a constant teflon coat in the inside of your engine so deposites and sluge cant stick their for getting trapped in the oil filter, when you switch from using mobile1 they claim it will eat up your seals due to the lack of teflon that was in the mobile1 oil


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## shipo (Jan 3, 2006)

*Re: (mk2allday)*


_Quote, originally posted by *mk2allday* »_synthetic oil molicquiles are half the size...

Ummm, no, that isn't exactly true. Conventional oil is kind of a mis-mash of molecular sizes, both larger and smaller than the relatively consistent molecular size of the components that make up synthetic oil.

_Quote, originally posted by *mk2allday* »_...so generally if you have a slight oil leak useing synthetic oil might make it worse due to its detergents and other aditives...

While that may be true in some extreme cases, as a general rule, introducing synthetic oil into an older engine will NOT cause leaks to develop.

_Quote, originally posted by *mk2allday* »_...yes syntheitic is a very low friction oil...

Once again, that isn't precisely true. I've yet to see any verifiable science that proves that synthetic oil is any "slipperier" than conventional when both are the same grade and are up to operating temperature. That said, due to the fact that synthetic oil "flows" better when cold, it does lubricate better following a cold start, especially during winter-time.

_Quote, originally posted by *mk2allday* »_...if you have a leaky engine i do not sugest you do an egnine flush because any gunk of the inside of your engine cloging up those leaky spots would become loose and your would leak again i see it happen all the time,you can allways switch on and off between conventinal oil and syntetic oil but not mobile1, mobile1 oil has teflon in it and every time your engine is running their is a constant teflon coat in the inside of your engine so deposites and sluge cant stick their for getting trapped in the oil filter, when you switch from using mobile1 they claim it will eat up your seals due to the lack of teflon that was in the mobile1 oil 

Where on earth did you dig that up? Fact, no oil on the market, Mobil 1 included, contains Teflon. Period, full stop, the end.








As for not switching back and forth between conventional oil and Mobil 1, that's just silly, and while I don't recommend such a practice, folks do it all of the time (i.e. they run Mobil 1 during the winter for its cold start capabilities and then say Havoline conventional oil in the summer).


_Modified by shipo at 10:16 AM 8-13-2008_


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## YikeGrymon (Sep 12, 2005)

*Re: (shipo)*

Well, the deed has been done. Six weeks ago.
First thing I noticed immediately is that the "new oil" feel of the engine (most notable upon startup, then you're not as aware of it after a coupla weeks... those of you who are as anal as I am and/or as attuned to how things feel and sound know what I mean) is the new norm. Especially on those cold mornings, which we've had a good number of by now. No more of that chilly-A.M. "scraping to life" sensation on startup. Just unbelievably smooth. So this is very cool.
Had a UOA before the switch; results indicated surprisingly little wear and nothing else amiss. All numbers were below the "universal averages" for my engine type, some WAY below. Far out. So I think I will be changing every 5K now.
Have not seen any evidence of synth "creating" or "revealing" leakage. So I guess all those who've said "Yeah, it's possible, but mostly sort of a myth" are correct.
Nice.


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## tjl (Mar 24, 2001)

*Re: Switch to Synth? (YikeGrymon)*


_Quote, originally posted by *YikeGrymon* »_I'm thinking of switching from "conventional" oil to synthetic. Car has just about 60K on it, oil has always been changed at good intervals (5K max, or 6 months max for those slow-mileage periods... car has pretty low miles for its age). Now I'm wondering about a few things:

Doesn't your 2000 VR6 engine specify 5W-40 oil (only available in synthetic in the US) at 10,000 mile or 1 year oil change intervals?

_Quote, originally posted by *YikeGrymon* »_• What's the story with a change to synthetic oil "revealing" or "creating" leaks that weren't there before? And do those leaks sort themselves out after a while?

The story that I read was that conventional oil sludge may be clogging up leaks, and the synthetic can clean out the sludge and reveal the leaks. But if your engine does not leak, no leaks will be revealed. If leaks are revealed, they needed fixing anyway.

_Quote, originally posted by *YikeGrymon* »_• Is there a flush procedure I oughta do before making a change like this? Or does the car not care (I imagine after one or two changes with synthetic, it wouldn't matter much)?

No special procedure.

_Quote, originally posted by *YikeGrymon* »_• Any brand/weight the preferred one to use?

Your owner's manual probably says 5W-40. An updated notice from VW from around 2004 or 2005 says to use VW 502.00 rated oil in 1998 to then-current VW gasoline engines.


_Modified by tjl at 8:30 PM 11-26-2008_


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