Slow2.8

Ive been puttin synth. in my 6 for a about 5 changes now. I was wondering if you switch to regular or even the "blends" without problems.. Or is it once you go synth you cant go back....???

rx7speed

you can switch back and forth without any problems

Slow2.8

cool, cuz imma do a few flushes with regular oil, would b too expensive with synthetic, thanks for lettin me know

vsixtoy

Just don't put full sythetic in an older motor, it will leak oil like a sieve.

edit; had to look up the word sieve . Been out of school too long

rx7speed

synthetic shouldn't just start to make things leakif things are doing ok

added synthetic to my car with 212k miles on the clock and she runs fine and doesn't leak anymore oil then with dino juice

would almost say it leaks less but I'm not goign to say that since I am not sure yet

vsixtoy

I was stating a fact

rx7speed

can you explain the fact?


can you explain high mileage?


can you explain this rather then just say it is fact?



or is this fact somethign you heard from someone else as heresay but sounds good enough it must be true?



not trying to be rude just too many forums where ppl put forth too many facts that come from too many unreliable sources

vsixtoy

A typical motor that has run aprox 100k on standard motoroil has a specific wear pattern on the seals from the standard larger oil molecule. It has been lubricated by, and thus worn to retain that size molecule.

Synthetic molecules are much smaller than standard motoroil molecules, thus they will seep through a seal that has normal milage wear patterns from standard oil molecules.

This is fairly common knowledge from those that have ever tried synthetics.

I have personally been running full synthetics since they derived on the market about 15yrs ago.

camaro_junkie

Sounds like a good explanation to me.

rx7speed

don't really see something leaking only on the melecular level being that big of a leak

i mean if something can't fit a .0005 micron molecule but can leak a .001 micron molecule don't think that it is going to cause the largest leak in the world if really a noticable one at all being it is only able to leak molecules at a time rather then nice drops at a time
(numbers just for reference)

now I can see it leaking a little more due to cleaning off the gunk that was in place from which reduces the seal being that the gunk WAS the seal then yeah

or leaking being that the oil even though it is the same weight does seem to not have as much surface tension (sorry asleep can't find the right words) allowing it to work it's way through th ecracks

and not all cars are prone to this
part of the joy of owning a car is taking cae of it
keeping the oil system clean and prevent the build up of gunk in the first place that can wear out seals as well as keeping the acid content down in cars which again can wear out seals and such
if the car was well maintained you shouldn't have too much of a problem with leaks

kinda like the car I have no yes I leak oil mainly from one spot though which is the oil cooler and then a little burning of oil which if it didn't happen I never would have bought the car
but the leaking dowsn't seem to be any worse and maybe (again can't verifiy for sure) less leaking then I had before

it isn't just simple as ok you have lots of miles your going to leak now

many other factors in it then just that

Doward

Yep... I've had cars that were extremely well taken care of, and over 130k on the odo, switch to mobil 1 synthetic. No leaks.

On the other hand, when Vortex and I rebuilt the 3.1, there was a steady drip (approx 1 drop ever 15 seconds) after shutting off the motor, reminding me I had forgotten to replace the old, dried up distributor O ring.

Fact is, synthetic flows better, and will get to more places than regular dino juice. That same property also means it will find ANY leakable spots in your motor.

Slow2.8

well i put in syn. in for a good 6 changes with no drops of oil, anywhere... didnt have leaks before switching though. had about 125k on the motor. Switched directly from old to synth. My motor is really dirty though, i know this b/c the oil gets dirty rather quickly since synthetic is supposed to b really good at cleaning engines, so im going to flush it a few times to clean it out then switch back to synthetic.

devianb

I second that, I swap, switch, and blend on many occassions, no leaks no problems.

mory

ok i just put 10w 30 in mine with 127221miles on it. it was valvoline synthetic. was this wrong?

Gumby

It is a know fact that allot of hi miles cars will leak after going synthetic but its not worth bickering over. But I never heard if happening with off the shelf synthetic. Its happens more with real synthetics like Amsoil other that are $20 a quart last 7000miles before it needs changed. They are better oils that seam to find their way out easier. Where off the shelf stuff gunks up n seals leaks.

TechSmurf

Back by request... Consider this thread 'On Probation'... and keep it clean, because if the flame war that was building up does errupt.. well.. let's just not go there unless we have to.

Fire"Dutch"Bird

iTrader: (1)

I agree with RX-7.
I changed a lot of engine and gear oil in a lot of cars and bikes, new , older and old, from dyno to synthetic, and sometimes back to dyno, NEVER ever any oil leaks, due to synthetic oil...!!
So use what ever you like, and when an oil leak occurs, it was going to leak anyway!!
In theory there's a very small chance for oil leakage when going from dyno to synthetic, that's because synthetic oil is slightly "thinner" than dyno oil from the same weight, so I'm always going up one weight class, to be sure, the heavier weight synt. oil has the benefit of a stronger oilfilm too, (means better protection).
It means going from for example dyno 10W30 to synt. 10W40 oil.
It's the last digits that's important, the weight when the oil is hot, that is!

TomP

The way I figure it, try the synthetic; if the motor doesn't leak, cool. If it does, well, go back to normal.

But I've always had normal oil in my motor, and, well, it's still going strong.

rx7speed

problem though with using 10w-40 or any large spread on the weights is the thingies that help make the weight change do end up breaking down and causing sludge and other deposits and tend to break down a lot quicker then oils with a smaller spread

then think I heard something that even though 20w50 might be thinner then 10w30 sometimes 10w-30 might be better

with the thick oils it doesn't get between bearings as easily or something like that but don't hold me to that one since I'm not sure there
just heard it and little tired so yeah :-)

Fire"Dutch"Bird

iTrader: (1)

Hey RX,

I'm using Castrol RS (Racing Synthec) 0W40 in my Formula, the best oil imo!
Used to use Castrol 10W60 in it, but Castrol recently changed the weight to 0W40.
Still use 10W60 Castrol RS in my Alfa Romeo though!
And yes, overhere in Europe, Castrol Synthetic IS synthetic, it's made in their German, Hamburg plant.
As I deal with a lot of different engines, car & bike, 2-stroke and 4 stroke, from 1 cilinder to 8 cilinders and from 50CC to 5700 CC, oil is very important to me, and after a lot of experience, and some mistakes too, I'm convinced the Castrol Synthetics are my brand!!

vsixtoy

This is a sensible person who understands what I meant exactly-Thanks Tom

I speak from experience- No nothing "always" happens, but in general its a known fact. Had the problem myself with two different cars I put it in. They had to switch back from synthetic and it stopped leaking. Yes I am talking "FULL" synthetics also, not the cheap blended stuff.