Re: From non synthetic to synthetic oil.
 

In addition to what youz guyz said the only real advantage of synthetic is the crank/startup phase of an engine, particularly in extreme cold situations. Not the case here in the 757. With that in mind, as well as other factors mentioned here, you'd be wasting your money. Stick with conventional, perform your oil changes on time and you'll be fine.

Re: From non synthetic to synthetic oil.
 

Synthetic will protect your engine better, there isn't much dispute over that, it's more stable with temperature and lubricates better.
Whether it's worth it to switch after all that mileage is a different story. Synthetic oil doesn't make seals and gaskets swell like conventional oil does, which is the big reason that it makes older engines leak, and doesn't affect new engines (whose seals are in good condition). Replace the seals and you're fine.

I'd just run conventional oil and then use synthetic if and when you want to rebuild that engine; you're not really buying yourself anything with that amount of mileage already on it.

Re: From non synthetic to synthetic oil.
 

synthetic oil is also what used car dealers use to sell their lemons cause it doesn't smoke.

Re: From non synthetic to synthetic oil.
 

wow,theres alot of mis-information being posted just on this thread. Can any of you back up your information with hard evidence that "synthetic oils are thinner",or that is will make older engines leak,or that conv. oils make gaskets swell,and syn doesnt? Or are these all just hear say that people have heard over time and time again?

Heres the truth,you CAN use synthetic oils in older engines WITHOUT any problems occuring AS LONG as there were no problems to begin with. NO switching to synthetic willnot make your car leak,NO synthetic arnt "thinner" then conv. oil, NO conv. oil DOES NOT make your gaskets swell. The only oil that makes your gaskets swell is High mileage oil. The reason they put this additive in high mileage oil,is because high milage engines tend to leak. So to compensate for that,they put an additive in high milage oils to 1,stop leaks,and 2 to prevent leaks.

The only difference in synthetics and conv. oils is one is man made,and one is naturally made. If you have 10w30 of dyno oil (conv.) and 10w30 of syn oil,they are the same viscosity,neither is thinner nor thicker. The advantage is that Synthetic oils lubricate better (due to additives in the "man made" process),They can take heat a hell of alot better (which raises its thermal breakdown point),Have better lubricating properties in high rpm applications (again,due to additives) and so on.There are many adv. to synthetics over dyno oil,which is why it costs alot more.

Now as said,switching from 10w30 to now 5w30 MAY....again MAY cause leaks that have not been present,to now be present. but switching from dyno oil to synthetic oil will not cause leaks. period. This has been a myth Plaguing the automotive ind. for years,and have been proven by oil companies,car companies,engine manu. to be not true through tests. And i can back all this data im saying up with various write ups and tests. none of this is what ive heard,or hearsay,its all fact.

Im not trying to step on anyones toes hear and say "YOUR WRONG!",so if it came across like that,then i apologize,dont take it like that. Im trying to spread good information to those that dont know,or that are just going off what they have grown up to know,or have heard. The whole point of car forums is to interact and learn,correct? Well it would be wasted learning if i cant turn around and teach what i now know. So no one take offense to my post,im just trying to dispel the myth,and impose fact.

Re: From non synthetic to synthetic oil.
 

No offense taken. We're all trying to help this guy. After everything you posted you missed his question entirely: Run it or don't run it? I say COMPLETELY unnecessary and a waste of $$$.

Re: From non synthetic to synthetic oil.
 

point taken,sorry OP i didnt answer your ?. I say it like this,if your going to granny it around town,then why spend the extra $$ like bmw said,just go with dyno oil. But if your going to race your buddies,occasionally go to the strip, dog on it from time to time,then id spend the extra few bucks for the extra protection. Its all up to you,and how you use your car. Me personally id shell out the extra couple bucks just to have that added protection.

Re: From non synthetic to synthetic oil.
 

He helped the original poster answer for himself, which is what all posts should do. I don't want people telling me what to do, I want people educating me so I can help myself.

Re: From non synthetic to synthetic oil.
 

Nobody's telling anybody what to do. Don't misconstrue what's being discussed here. Here...I'll clarify:


IMO...

Pros:

* Better protection of engine parts, particularly in exreme heat/cold situations. The greatest damage to your engine occurs the first minute you turn it on. (unless you beat the shit out of it, which you said you didn't)

* Slower breakdown of oil

* Because of their higher flash points, and their ability to withstand evaporation loss and oxidation, synthetics are much more resistant to sludge development.

* Synthetics can greatly extend drain intervals (My Bimmer uses Castrol Syntec Synthetic and gets changed every 15,000 miles per BMW specs), provide better fuel economy, reduce engine wear and enable vehicles to operate with greater reliability. This offsets initial price differences. Thus, the benefits of using synthetic oils could perhaps turn out to be more economical than conventional non-synthetics.

Cons:

* The old adage, "If it ain't broken....."
* Money's tight for you
* Is it worth it to you to use it in a car with that much mileage?
* If you don't keep cars long, it's hardly worth paying $5 a quart instead of $1.50


Keep in mind the functions of additives can be offset when oils with different additive packages are put together. For optimal performance, it is better to use the same oil throughout. Just drain, change the filter and fill/refill using the same product. If you DO decide to do this, Wal Mart sells Castrol Syntec in 5 quart contaners for @ 30 bucks and change, if memory serves me right. That's the best deal I've seen around.

Hope this helps. Good luck with your decision.

Re: From non synthetic to synthetic oil.
 

Exactly...that's what I said. Nobody is telling him what to do, because as you just said yourself, there are a lot of different factors in his decision. And all JDMTeg18 did was show unbiased, proven facts. He helped the OP decide on his own, like I said.

Re: From non synthetic to synthetic oil.
 

IMO......I used to run Castrol Synthetic Blend, I changed over to it ~180K. A. I used to dog my Z6 on occasion B. has the additives with conventional oil. When I pulled the motor out to swap in my LS-VTEC motor, I pulled the head off after sitting for a year on my garage floor and revved to 8500RPM before it was pulled out. most people that looked at the head (I was going to build a n/a high comp Z6) would swear it had only ~80K miles on it (actually had 223K). Now granted I did change my oil every 3-5K miles and it ran like a dream! If you hit VTEC on a daily basis whether WOT or not I would switch to at least the synthetic blend if you thinking about switching over. again just my $.02!