Topic: synthetic oil?
in Forum: C3 Engines
hi everyone.
i'm sure this has been discussed before and i'm half afraid to open this can of worms 
, but i'm thinking about switching to a synthetic oil. my car has 106,00 or so miles on it and i'm looking for opinions on whether or not synthetic is better than conventional oil. also, what about oil additives like slick 50? are they safe? i'm just trying to tighten up my motor and keep it together for a couple more years.
thoughts.......?
Jeff, I don't think there's any question as to whether synthetic oil is better than conventional oil. As for "tightning up your engine", synthetic oil will definetely not do that. If fact, it may have the reverse effect. I use Royal Purple oil and the following is from their Q&A.
Will synthetic oil cause my engine to leak?
Properly formulated synthetic oils will generally not cause an engine oil leak. Synthetic oils possess a higher degree of natural solvency, which can clean and remove deposits left by other oils. The removal of extensive oil deposits can expose marginal or damaged oil seals that may then leak. If an engine currently has excessive oil consumption (i.e. greater than 1 quart / 1,000 miles) the recommended course of action is to solve the oil consumption problem before switching to a synthetic.
Should I use an oil additive with Royal Purple®?
No. We strongly recommend against using any oil additives as do most automotive manufacturers. Engine oils are formulated with a fine balance of additives (anti-foam, corrosion inhibitors, anti-wear, detergent / dispersants, oxidation inhibitors) and more is not necessarily better. The use of an oil additive could upset the balance resulting in reduced performance
Hope this helps.
Lifetime MemberWell, I’m not a mechanic by any means, but I can say this about Slick 50. I had an old truck (250,000+ miles) that I used it in. The thing started to leak oil, and I didn’t want to fix the problem, as I was preparing to junk it out soon.
Loaned the truck to a neighbor for a month while his was getting fixed. After I junked it, he asked me what did I put in the oil? Seems that twice, he ran it all the way completely empty on oil, and only put it in when the lifter noise got to him. (And he wonders why he can't drive my Vette?!?!
)
I owned the truck since almost new, and the only thing I can think of that saved it from freezing on him was the Slick 50.
That was my experience with it, I look forward to hearing back from some of the professionals here.
As for the synthetic oil, I use it in all my cars, but for a different reason then I think you are looking for. When you use synthetic, you get more miles between oil changes. I go for 7,000 miles between changes. It’s just that 2 of my cars get high mileage put on them (30K+ a year). The Vette’s get it just so that I use the same oil in all of my cars.
Lifetime Member #36 
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After switching to Schaeffer in 1998, we have had maybe three bearing failures. And after 100,000 miles the engines are extremely clean at teardown. I am a firm believer in synthetics. I use Schaeffer in all of my personal vehicles. When I rebuild the Vette I will use Schaeffer oil.
Having said that, I would never switch to synthetic after using a pure petroleum lubricant up to that point. Even most of the synthetic suppliers recommend against that practice. Go to some of the different websites and read up on the products. I think you will find a ton of good information.
Good luck,
Scott
Lifetime MemberIMHO humble opinion...I WOUL NOT SWITCH....
I do run Synthetic in my newer vehicles ...BUT in my TOYS (The older
Corvettes) I just enjoy being in the garage playing with them. And changing oil is part of what I think of as Playtime..
I change the oil in all of them every 1000 miles ...plus store them with fresh oil every Winter...and put frest oil in then every Spring...changing the filters every other Oil Change...
Its overkill I know..>BUT I honestly enjoy doing it...Have lifts, have oil
have time, (I'm retired) why not...!
I may be wasting a little money..BUT have any of you took the grand kids to a movie lately...The OIL CHANGES ARE DIRT CHEAP..and they
help me relax...
Bob G.
Bob
64,72 & 98 Corvette Ragtops
76 & 79 & qa 88 ANC Corvette Coupes 
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With all the cars you have I think you must have a refinery behind your garage! That's the only way I can see making it cost effective!
Regardless, I'm sure the insides of your cars' motors are squeeky clean. No wonder the guy who bought your '95 did so as soon as he walked in your garage and looked at your fleet.
Lifetime Member
. 
Syuth oil is excellent, but the cleaning action in a higher mileage engine could cause leaks. At 106,000 I think I would avoid them unless you plan on doing leak repairs.
I have tested several products in great detail. When I was teaching for Allen Test Products, and when I had my own shop I had the ability to test many, many different things. Between the equipment an a large source of vehicles I could track, I found a lot of things.
First, I do not recomment oil additives in place of a good oil in a good engine. A worn engine can benefit from some additives, depending on the problem at hand.
However Slick 50 is a metal treatment, not an oil additive. It is added to the oil, but treats the metal. This is apparent due to the fact it only need be added once every 50,000 miles. Oil additives need added everytime.
Slick 50 does work. I can give some remarkable examples of real work results. It is an excellent product to use in a mid or high mileage engine. With over 100,000 miles I would recommend it instead of synth oil.
I do in fact use slick 50 in two of my cars. I just did engine work in the Vette. After it is broken in, I will use Slick 50. After that I will probably use synth oil.
thanks for the feedback guys!
i was under the misconception that synthetic would kind of "gum" up the motor, thus making it "tighter". but it seems like a leak waiting to happen instead. i think i'll stay away from it at least for now (since i already have a small leak at the front seal). i'll do some more oil research. might try the slick 50 though.
thanks again!
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