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Dnyce
05-05-2008, 02:15 AM
why cant you go back to dino after u go full synth? no smartass answers like why would you wana go back, etc etc. everyone says once you switch, you cant switch back. why the hell not? never got a straight answer. some oils are semi synth....im not changing oils-but i like knowing how shit works.

marko138
05-05-2008, 08:25 AM
I had heard that years ago...but I'm told now it isn't a big deal if you get all the old Synth out first.

Trip
05-05-2008, 08:33 AM
it has something to do with mineral oil coating being thicker than synthetic and the tolerances your engine develops running synthetic.

6doublefive321
05-05-2008, 09:59 AM
I would think you can, as long as you do a good flush out. That is, drain the syth, fill up with dino, run for a few minutes. Drain and repeat. Its hard for me to believe that what little synth is left could damage your engine.

Speaking of which, what about "semi-synthetic" oils? What's the difference between having a little synth left over and using a semi-synth oil? Maybe there are some stabilizers in play to eliminate any incompatibilities?

t-homo
05-05-2008, 01:20 PM
I use a "parasynthetc" or blended oil. They say if I ever run low and need to get some, I can get conventional and add to it but not synthetic. Don't really know why.

Amber Lamps
05-05-2008, 01:45 PM
I got this from Mobile1's website,


Can different synthetic motor oils be mixed together?

Mobil 1 is fully compatible with conventional motor oils, semi-synthetic motor oils and other synthetic motor oils, should it be necessary to mix them. However, it is important to note that the superior performance of Mobil 1 will be reduced by diluting it in any way.

They also dispute the need to breakin a motor using dino and the need to flush a motor before using synth. There wasn't any mention of flushing before going back to dino. Altho',I don't get why you'd want to flush out the good stuff before putting in the cheap crap. That'd be like making sure you rinse your glass before switching from Grey Goose to Heaven Hill!

it has something to do with mineral oil coating being thicker than synthetic and the tolerances your engine develops running synthetic.

Um doesn't viscosity determine an oil's "thickness" and if so wouldn't ANY 10W40 oil be the same? I always thought the "superiority" of synth was it's ability to retain it's viscosity for longer under harsher conditions.:idk:

Trip
05-05-2008, 02:22 PM
Um doesn't viscosity determine an oil's "thickness" and if so wouldn't ANY 10W40 oil be the same? I always thought the "superiority" of synth was it's ability to retain it's viscosity for longer under harsher conditions.:idk:

Not the viscosity of the oil, the thickness of the coating on the parts they are lubricating.

Parts getting use to running with a thinner gap than is required with dino lubricants, where dino runs at a larger gap.

Amber Lamps
05-05-2008, 03:06 PM
Not the viscosity of the oil, the thickness of the coating on the parts they are lubricating.

Parts getting use to running with a thinner gap than is required with dino lubricants, where dino runs at a larger gap.


hmmm...so you're saying that your oil can determine how far apart the metal parts in your engine operate from one another and that synth oil puts a "thinner" coating on metal parts than dino oil does? I always thought that the tolerances in your motor are what they are,minus wear ofcourse,and your oil can't affect that other than by allowing wear. For the most part,internal components are surrounded by oil,so the gap is always going to be the same no matter what you run. How can you increase the gap on one side of a part without reducing the gap on the other side? Unless you are stating that dino oil "compresses" parts,making them smaller,thus allowing for a larger gap all the way around.

Anyway,I've checked a couple of other websites and they all state in their faqs that it's ok to run/mix synth with conventional oil and to change back and forth at will.

Amber Lamps
05-05-2008, 03:54 PM
Repsol;
- Can two lubricants be mixed in the same engine?

All lubricants on the market (whether petrol or diesel engines, mineral or synthetic) can be intermixed. Nonetheless, mixing two different quality oils reduces the overall quality.

- What is the difference between a synthetic and a mineral lubricant?

A mineral lubricant is made up of a base obtained directly from oil distillation plus some additives which improve its performance.

With a synthetic lubricant, the bases are treated through a physical/chemical process in order to obtain a higher quality and performance. With semi-synthetic lubricants, mineral and synthetic are combined.

- Are synthetic lubricants the best?

Yes. Synthetic lubricants have been specially created to respond to the demands of the engine or to be used in extreme temperatures and very intense service conditions.•

Castrol;
Can I switch between a synthetic and a conventional oil?
It is a common myth that you cannot go back to a conventional motor oil after using a synthetic. All of Castrol's oils are fully compatible with one another, and there is no cause for concern if you choose to switch from conventional to synthetic or vice versa. Another common myth is that you cannot switch from a conventional oil to a synthetic oil without first flushing your engine. If you currently use conventional oil, you do not have to flush your engine before you switch to Castrol SYNTEC.


Valvoline;The Aging Standard
Conventional motor oil has been the benchmark in engine lubrication since Carl Benz invented the car in the late 1800s. Over the years, oil manufacturers have improved the refining processes to remove impurities. Still, mineral-based oil, even in its most pure form, remains somewhat imperfect.
This liquid lubricant performs two primary functions inside your engine. It reduces friction between moving parts, and it dissipates heat created by the combustion process. At normal operating temperatures, conventional oil protects the internal workings of your engine. This ability to protect as well, however, when engine temperatures rise or fall below the norm (as you would find upon start up, during spirited driving or in extreme climates) is limited because at lower temperatures conventional oil becomes thick, or more viscous. (NOTE,vicous=thick,Tig) In this state it may have difficulty reaching critical components. At higher temperatures, the same oil often becomes too thin to adequately coat and effectively protect moving parts.
Synthetic oil, on the other hand, has a higher tolerance for temperature extremes, thereby maintaining a more consistent viscosity. This means your engine is better protected overall regardless of engine operating temperatures.
Size Does Matter
Synthetic oil is also more resistant to thermal and oxidative breakdown, processes that occur when oil is exposed to the severe conditions inside an engine. When motor oil begins to break down, it is essentially burned away, which causes it to lose its ability to protect valuable engine parts and dissipate heat.
The reason for synthetic oil's increased resilience stems from its uniform molecular structure. Conventional base oil is composed of several sizes and shapes of hydrocarbon molecules. This variation brings with it a range of evaporation, oxygenation, and burn points. Included in the mixture are some comparatively unstable molecules, some of which break down very soon after the conventional oil is poured into your car. This forces the remaining oil to work harder.
To overcome the problem of thermal and oxidative breakdown, synthetic base oils are created through a series of chemical synthesis. The starting materials may be a mixture of relatively pure small molecules. In this case the small molecules are combined to make new, larger molecules. Alternatively the starting material may be a broad mixture of larger molecules. In this case the large molecules are broken down and rearranged. The result is motor oil that is composed solely of pre-selected similarly sized molecules devoid of any weak links that inhibit performance. The new molecules are specifically shaped to offer optimum lubrication and maximum resistance to thermal breakdown.

Anyway,that's just a few of the sites I got from a google search.

Trip
05-05-2008, 05:15 PM
hmmm...so you're saying that your oil can determine how far apart the metal parts in your engine operate from one another and that synth oil puts a "thinner" coating on metal parts than dino oil does? I always thought that the tolerances in your motor are what they are,minus wear ofcourse,and your oil can't affect that other than by allowing wear. For the most part,internal components are surrounded by oil,so the gap is always going to be the same no matter what you run. How can you increase the gap on one side of a part without reducing the gap on the other side? Unless you are stating that dino oil "compresses" parts,making them smaller,thus allowing for a larger gap all the way around.

Anyway,I've checked a couple of other websites and they all state in their faqs that it's ok to run/mix synth with conventional oil and to change back and forth at will.

The matter in between moving parts can determine the tolerances as wear sets in because they are a factor in the wearing process. This may not be something of concern at all in a motorcycle engine, it may have stemmed from an engine that's tolerances are a lot more unforgivening. I am just simply stating what I have heard for why you aren't suppose to change back and it may be something that isn't even a concern for these engines. Instead of being completely unhelpful to this topic, why don't you try researching why this notion was started that you can't go from syn to dino.

Amber Lamps
05-06-2008, 12:54 AM
The matter in between moving parts can determine the tolerances as wear sets in because they are a factor in the wearing process. This may not be something of concern at all in a motorcycle engine, it may have stemmed from an engine that's tolerances are a lot more unforgivening. I am just simply stating what I have heard for why you aren't suppose to change back and it may be something that isn't even a concern for these engines. Instead of being completely unhelpful to this topic, why don't you try researching why this notion was started that you can't go from syn to dino.

I'm not sure what you mean but particles in the oil could affect tolerance by wearing down parts but I don't think that the type of oil would be a factor in this case. Other than synth's ability to suspend particles better of course. I really don't see how oil can affect tolerance but hey you're the boss so...

I'll look into the origins of this myth but I'm sure it'll end up being the usual situation. People don't know the answer or they don't understand something so they make stuff up. If the same stupid therory is repeated enough times,it becomes the rule. Just like how people believed the world was flat. Some ass was asked what the shape of the world was and instead of admitting he didn't know,he made something up. Simple.

My own half assed opinion on why you can't swap back would be that because synth is a better lube and bonds to parts better,maybe it masks bearing probs. So when you switch back to the inferior dino oil,you get failures and/or elevated engine noise as the synth is "washed" away. Or just simply,you get used to synth's superior properties; engine runs cooler,less noise,etc,then you put dino in and your motor is noisier,runs hotter,etc.

ceo012384
05-06-2008, 01:06 AM
Several people with shit-tons of knowledge that I would consider trustworthy have told me it is not true.

I can think of potential arguments to go in both directions that would make sense, but I have no idea.

Whether or not it USED to be true and now isn't, I'm not sure.

Dnyce
05-06-2008, 01:09 AM
based on what ive heard, 10w-40 was 10w-40 whether synth or dino, that was the main reason i never understood why it was believed you cant switch back.

it would seem that the thickness of the coating on the parts would only matter at start up, when the engine is "dry" because a thicker coat would decrease initial wear maybe-but if you can have a thinner coat on the parts yet still have the same friction coefficient, then it shouldnt matter i think. but thats off on a tangent-

anyway pertaining to the question-could it be that early synths had additives that reacted to the additives in the dino oil that destroyed seals? actually that dont make sense because then it shouldnt be compatible at all, dino to synth wouldnt be possible either.

just throwin stuff out there. i think it could possibly even be that some ppl took their vehicles to the dealer, took a chance and tryed synth-and didnt notice a difference that was worth the extra money. instead of switching back and saving money, they were told they couldnt switch back. cars come with synth now (most do i believe) so you have no choice but to use the more expensive synth. no more $15 oil changes. just another idea....

obviously u can switch back and forth with no problem according to the oil companies, so who the hell started this myth lol

Amber Lamps
05-06-2008, 01:25 AM
based on what ive heard, 10w-40 was 10w-40 whether synth or dino, that was the main reason i never understood why it was believed you cant switch back.

it would seem that the thickness of the coating on the parts would only matter at start up, when the engine is "dry" because a thicker coat would decrease initial wear maybe-but if you can have a thinner coat on the parts yet still have the same friction coefficient, then it shouldnt matter i think. but thats off on a tangent-

anyway pertaining to the question-could it be that early synths had additives that reacted to the additives in the dino oil that destroyed seals? actually that dont make sense because then it shouldnt be compatible at all, dino to synth wouldnt be possible either.

just throwin stuff out there. i think it could possibly even be that some ppl took their vehicles to the dealer, took a chance and tryed synth-and didnt notice a difference that was worth the extra money. instead of switching back and saving money, they were told they couldnt switch back. cars come with synth now (most do i believe) so you have no choice but to use the more expensive synth. no more $15 oil changes. just another idea....

obviously u can switch back and forth with no problem according to the oil companies, so who the hell started this myth lol

Who knows? Like I said people make shit up! Btw I used to work for Ashland and one of my best friends works for Mobile and last I knew,because of manufacturing costs and price competition,the profit margin on synth isn't any better than dino,so the oil companys don't care which you use,as long as you keep changing it every 3000 miles!$$$$$$$$$

Dnyce
05-06-2008, 01:46 AM
yea-i typed my post as u posted

Amber Lamps
05-06-2008, 02:10 AM
yea-i typed my post as u posted

Happens to me all the time! my left hand was crushed/cut in half in an accident,so I can't type worth a fuck anymore!

btw I almost forgot,when synth oil first came out we used to market it as a "bargain" based on the fact that you could go "twice as long in between oil changes". The funny thing is that most "experts" agree that there isn't any reason to not go 5000 miles between oil changes with dino,so excusing the higher price of synth based on a 6000 mile lof was marketing genius!!!

My buddy showed me a study where they ran a car for 100,000 miles,changing only the filter and topping off every 10,000. Drained the oil and found that it had only lost 11% of it's original viscosity. He also claims that you can run Mobile1 for 3000 miles,drain it,filter it,replace the additive package and put it right back into your bike 3 or 4 times before you'd have to replace it.:idk:

Trip
05-06-2008, 07:33 AM
Found the reason why this was started. Old seal tech use to leak when you switched from one to the other, but if you have a newer bike you have nothing to worry about. If you have an older bike, it would be advisable to watch for leaky seals and oil comsumption.

Rider
05-06-2008, 08:38 AM
Repsol 4T Sintetico FTMFW. Smoother shifts than with KawiChem or Golden Spectro semi synthetics.

marko138
05-06-2008, 08:59 AM
Repsol 4T Sintetico FTMFW. Smoother shifts than with KawiChem or Golden Spectro semi synthetics.
Thats what I use in the Zuk.

Trip
05-06-2008, 09:04 AM
I use Honda HP4S full syn. I used Honda mineral for awhile, but I like the way the shifting feels with the full syn. Shifting stays silky smooth for the entire life of my oil. I change my more frequently than is needed though.

Rider
05-06-2008, 09:14 AM
Thats what I use in the Zuk.

Plus it's cheap... I get a 4L jug for $25

marko138
05-06-2008, 09:15 AM
I always bought by the liter...I like single better.

Amber Lamps
05-06-2008, 10:30 AM
I always bought by the liter...I like single better.

Yea the Repsol bottle with the tube in it is worth the extra buck by itself!
I've been using Suzuki full synth lately 'cause I'm a bum and it costs $6 a qt for full synthetic. Ofcourse it's probably type III but it's still better than dino juice. I'm considering going back to Mobile1 since a guy I ride with here can get it for me for $7 a qt. It's type IV and I don't have to deal with Ron Ayers hours of 9-6 t-f and sat 9-2. They have the shortest hours I've ever seen and they're the only jap dealer in the area!

Rider
05-06-2008, 10:34 AM
Yea the Repsol bottle with the tube in it is worth the extra buck by itself!


What do you mean tube in it? It's a pain in the ass to pour right out of the container right into the bike due to the angle of the filler. I have to pout it into a smaller container so I don't sill it all over.

Amber Lamps
05-06-2008, 10:43 AM
Found the reason why this was started. Old seal tech use to leak when you switched from one to the other, but if you have a newer bike you have nothing to worry about. If you have an older bike, it would be advisable to watch for leaky seals and oil comsumption.


From Mobile1;

Myth: Mobil 1 will leak out of the seals of older cars.
Reality:

Mobil 1 does not cause leaks. In fact, new Mobil 1 was tested in dozens of industry standard and original equipment manufacturers (OEMs) tests to prove its seal performance. It is fully compatible with the elastomeric materials from which all automotive seals and gaskets are made. If an older engine is in good condition and does not have oil leaks, Mobil 1 provides the same advantages as when used in a new engine. ExxonMobil recommends taking measures to repair the leaks, then using Mobil 1. ExxonMobil also recommends following the automobile manufacturer's manual for the proper oil to use.

Where'd you get your info,Trip? The only thing I've heard was that if your vehicle already has leaks and sludge is "plugging" them,synth oil will clean out the sludge and let the oil flow out easier.

on a small side note,have you guys seen the Mobile1 High mileage oil yet? They claim a 15,000 oil change and guarantee no damage to your engine although I'm sure there are some provisos,etc. Still that's nuts!

Amber Lamps
05-06-2008, 11:06 AM
What do you mean tube in it? It's a pain in the ass to pour right out of the container right into the bike due to the angle of the filler. I have to pout it into a smaller container so I don't sill it all over.






here ya go...

Rider
05-06-2008, 11:10 AM
here ya go...

No shit? Yeah thats makes it worth the extra cost to buy it individually. I didnt know that was there. Thanks!

Amber Lamps
05-06-2008, 11:17 AM
No shit? Yeah thats makes it worth the extra cost to buy it individually. I didnt know that was there. Thanks!

Yep,I wish they'd all do that! Hey,make sure the tube is "locked" into place before you squeeze the bottle.......

6doublefive321
05-06-2008, 11:18 AM
From Mobile1;

on a small side note,have you guys seen the Mobile1 High mileage oil yet? They claim a 15,000 oil change and guarantee no damage to your engine although I'm sure there are some provisos,etc. Still that's nuts!

15,000 isn't that crazy. I drive a BMW car, and its computer monitors driving conditions, etc, and tells me when to change the oil. I change at 10,000 miles regardless of what it tells me, but the computer always tells me that it has 3 to 5k left before the recommended change! Granted the damn thing holds 6.9 quarts, but that's still amazing. Kind of debunks the 3k mile oil change myth, huh? There are numerous tests on taxi fleets, etc. that say there is no advantage to changing oil at 3k miles as opposed to say 7.5k.

Amber Lamps
05-06-2008, 11:24 AM
15,000 isn't that crazy. I drive a BMW car, and its computer monitors driving conditions, etc, and tells me when to change the oil. I change at 10,000 miles regardless of what it tells me, but the computer always tells me that it has 3 to 5k left before the recommended change! Granted the damn thing holds 6.9 quarts, but that's still amazing. Kind of debunks the 3k mile oil change myth, huh? There are numerous tests on taxi fleets, etc. that say there is no advantage to changing oil at 3k miles as opposed to say 7.5k.

True! I was mostly commenting on the guarantee part of it. I worked for Ashland and know for a fact that the 3000 mile oil change was nothing more than a marketing tool to get people into instant oil change places. I'm not sure but I don't think a single oem still reccomends lofs every 3000 miles. Even if they did,I'd still suspect it was at least partially a ploy to get people into their service bays for lofs!

Cutty72
05-06-2008, 11:25 AM
1125R manual says change oil every 6,000 miles using synth. change filter every other.

Trip
05-06-2008, 11:32 AM
From Mobile1;

Myth: Mobil 1 will leak out of the seals of older cars.
Reality:

Mobil 1 does not cause leaks. In fact, new Mobil 1 was tested in dozens of industry standard and original equipment manufacturers (OEMs) tests to prove its seal performance. It is fully compatible with the elastomeric materials from which all automotive seals and gaskets are made. If an older engine is in good condition and does not have oil leaks, Mobil 1 provides the same advantages as when used in a new engine. ExxonMobil recommends taking measures to repair the leaks, then using Mobil 1. ExxonMobil also recommends following the automobile manufacturer's manual for the proper oil to use.

Where'd you get your info,Trip? The only thing I've heard was that if your vehicle already has leaks and sludge is "plugging" them,synth oil will clean out the sludge and let the oil flow out easier.

on a small side note,have you guys seen the Mobile1 High mileage oil yet? They claim a 15,000 oil change and guarantee no damage to your engine although I'm sure there are some provisos,etc. Still that's nuts!

I will try to dig that link up. It was like thecarbible.com or some shit like that. They have changed the additives/chemistry of synthetics since this time as well which was also mentioned on the site that this problem may not be true with today's synthetics with older seals, but they said they couldn't guarantee it to cover their ass.

What may have been true in the past isn't necessarily true of present tech. Hence why people said don't switch from conventional oil to syn may no longer apply altogether.

Amber Lamps
05-06-2008, 11:38 AM
1125R manual says change oil every 6,000 miles using synth. change filter every other.

Ok question...do you have the BALLS to do it? J/K but Suzuki says about 3500 using dino juice and I can't bring myself to wait. Even tho' I KNOW it isn't necessary,I am so programmed to the 3000 mile change(if I wait even that long) that I get nervous when it's even close to that mileage! Amsoil promises 5 or 6000 but I always changed around 3000 when I used their product. That's why I mostly use Suzuki full synth,at least it's only $6qt. Plus I can't bring myself to not change the filter even tho' the manual says every 10,000 miles. Break the chains of our 3000 mile oppression brother! You can be savior that'll lead us into a new and brighter era!!! Cutty...Cutty...Cutty!!!

Trip
05-06-2008, 11:40 AM
Honda recommends 4000 miles on the new 600rr, I do it more than that if I am doing track days, but if I am tooling around just street for more than 4000 miles I wait longer than 3000.

marko138
05-06-2008, 11:45 AM
15,000 isn't that crazy. I drive a BMW car, and its computer monitors driving conditions, etc, and tells me when to change the oil. I change at 10,000 miles regardless of what it tells me, but the computer always tells me that it has 3 to 5k left before the recommended change! Granted the damn thing holds 6.9 quarts, but that's still amazing. Kind of debunks the 3k mile oil change myth, huh? There are numerous tests on taxi fleets, etc. that say there is no advantage to changing oil at 3k miles as opposed to say 7.5k.
My father-in-law runs Amsoil 20,000 miles between changes...he also sends it out to get tested and every time it's come back they say it's good for more miles.

Cutty72
05-06-2008, 12:29 PM
I probably will run it the 6K now with the synthetic.
Bought a case on sale for $7.50/qt. and that's the HD Screaming Eagle stuff.

But then again, it's only got 860 miles on it now, and it's getting it's second oil change.

Amber Lamps
05-06-2008, 02:07 PM
I probably will run it the 6K now with the synthetic.
Bought a case on sale for $7.50/qt. and that's the HD Screaming Eagle stuff.

But then again, it's only got 860 miles on it now, and it's getting it's second oil change.


I managed 2200 and changed my oil from Repsol $13 a liter to Mobile $7 a quart.

ceo012384
05-07-2008, 04:24 AM
15,000 isn't that crazy. I drive a BMW car, and its computer monitors driving conditions, etc, and tells me when to change the oil. I change at 10,000 miles regardless of what it tells me, but the computer always tells me that it has 3 to 5k left before the recommended change! Granted the damn thing holds 6.9 quarts, but that's still amazing. Kind of debunks the 3k mile oil change myth, huh? There are numerous tests on taxi fleets, etc. that say there is no advantage to changing oil at 3k miles as opposed to say 7.5k.

I'm sure the oil IS fine for that long... but there's something about it being so damn dirty when I change it after a couple track days that makes me feel better about changing it so often. Shit comes out wicked black.

Amber Lamps
05-07-2008, 09:01 AM
Popular Mechanics,
A: Early synthetics got a bad reputation for leaking. This was because, despite the claims of the oil manufacturers, the seal-swell characteristics of the new synthetics were different from those of the mineral oils they replaced. If the seal-swell rate was lower, the seals shrank and oil leaked from crankshaft seals and rocker cover seals. If the rate was higher, the seals swelled a little extra and the engine was tight. Then if the owner changed back to mineral oil, or added a quart when no synthetic was to be had, things got really bad. The crank seals had become worn, in their turgid state, and then relaxed. The valve cover seals were compressed when swelled, and when the different oil was added, everything leaked like, well, an old English sports car.

Fortunately, the situation has improved; you should have no problem switching back and forth. Adding a quart of mineral oil to a crankcase full of synthetic will be fine. Read the fine print — a lot of the "synthetics" on the market are blends containing a substantial proportion of mineral oil.


And that's the reason for not switching back and forth! Btw apparently this is from the 60s or 70s.....

Amber Lamps
05-07-2008, 09:18 AM
I'm sure the oil IS fine for that long... but there's something about it being so damn dirty when I change it after a couple track days that makes me feel better about changing it so often. Shit comes out wicked black.


Castrol
• I noticed that my oil seems to get darker with use. Can you explain this? [25%]
It is natural for oil to darken with use. This is an effect of the oil doing its job well. The oil will darken as it collects the contaminants from the combustion process, as well as handling the high temperatures that occur within any piece of machinery.


Shit,I've lost interest...anyway,there's a bunch of studies that suggest that stop and go traffic and parade laps are worse on you oil/motor than any beating you could give your bike on the track. Also,if you change your oil and run it around the block a couple times,it'll come out black.

Trip
05-07-2008, 09:26 AM
Popular Mechanics,
A: Early synthetics got a bad reputation for leaking. This was because, despite the claims of the oil manufacturers, the seal-swell characteristics of the new synthetics were different from those of the mineral oils they replaced. If the seal-swell rate was lower, the seals shrank and oil leaked from crankshaft seals and rocker cover seals. If the rate was higher, the seals swelled a little extra and the engine was tight. Then if the owner changed back to mineral oil, or added a quart when no synthetic was to be had, things got really bad. The crank seals had become worn, in their turgid state, and then relaxed. The valve cover seals were compressed when swelled, and when the different oil was added, everything leaked like, well, an old English sports car.

Fortunately, the situation has improved; you should have no problem switching back and forth. Adding a quart of mineral oil to a crankcase full of synthetic will be fine. Read the fine print — a lot of the "synthetics" on the market are blends containing a substantial proportion of mineral oil.

so yes, the second info I found about seals leaking is where this came from.