Too Slow '90

It's time for the next change and I'm toying with changing to synthetic. At two and one half times the price is it worth it? It's not a daily driver and I change at 3K. What are the benefits and what type and viscosity would be good? Any point in switching from the Delco filter? I've always stayed with the OEM filters. :chevy

65Z01

Full synthetic has the following improved properties:
1) doesn't thin quite as much at elevated temps
2) flows a little bette at low temps
3) is much more thermally stable
You still need to change it at regular intervals to keep the detergents and dispersents concentration up as well as get wear particles and acids out of the engine.
I use it (5W30) because I give my Vette some severe service in the 1/4 mi and I like the added protection (it's a frequent but not a daily driver). And full synthetic is recommended for our cars.

I use the stock type filter. The GM filter should be just fine.

JoeVette88

Is it true that once you start using synthetic, you shouldn't go back to regular oil? I heard that from somebody...

Just put in 5 qts of Mobil 1 5W 30 and GM Filter today... Next change will be at 103850... :(

Too Slow '90

Are there any grade differences? The manual says SG for regular oil. Also, Mobil 1 seems to be the most popular. Any manufacturer better than others?

satyr7777

sin-thetic is for cars that have been naughty, and haven't been to confession. :reddevil

Seriously- synthetic has alot of advantages, BUT I've heard over and over again that it's a bad idea to change to synthetic after the motor has over 60K on the clock- since it affects the gaskets, seals, and etc., and can cause a leaky oil-consuming mess. After a rebuild though- it's a good idea to start it out with mobil 1.

black86targa

I also have a 77 Ferrari. I use Castrol Synthetic in it. It gets hot enough in engine bay to cook eggs on the upper grill. Its also turbocharged, which makes it even hotter yet. It did use a quart of oil between changes. Now with synthetic it completely stopped using it. I use 5w50 year round in it. As soon as I get the new vette all flushed out, im putting it in it too. You can also go lots more miles between changes if you want. I change the Ferrari at about 5-7K or 3 times a year.

Rick93Z07

I have changed cars over to synthetic with 100K+ on the clock. Synthetic results in lower friction, so there is less wear. I would not run dino for fear of leaks with synthetic. Personally, I fear engine wear and overhauls more than a leaky $10 seal, so I have not run dino for 22 years. When you switch to synthetic, wear will virtually stop. You can change premium dino almost daily and it will still result in more wear than using neglected, blackened synthetic. An aggressive 3K mile service interval is not the answer. This has been proven in controlled lab testing. My prior track car saw sustained high RPM and wide open throttle on Road Racing Tracks with 240K+ miles on the clock and it still runs like new today (every day to work). This car has over 20K track miles on it and was retired from racing only because I bought a faster car. My Mobil 1 oil change interval on that car under severe duty use was every 25K miles.

Yello95

[QUOTE]sin-thetic is for cars that have been naughty, and haven't been to confession. :reddevil

:lol: :smash: :cheers:

Nathan Plemons

You want a good reason to go with synthetic? Get Glock 94 to post some pictures of his heads. They were neglected with Dino oil, NASTY. I can also show you some fine pictures of cars that have used synth from day 1 and they still look new.

jimbomill

Wow - my '92 (my first Vette, finally) is that exact situation. I was unsure of the type of oil used, so I had my local shop put in an oil change with Mobil 1 and do the rear differential, right after I bought the car. The NEXT day, I had an oil leak, plus, the ASR now comes on after the car tries to go from a full stop (either First gear, or reverse). The seals had to be replaced and we are still touble shooting the stinkin ASR problem :)
Do you know why the synthetic causes a leak ?

92TripleBlack

The particles of true synthetic oil are the same size. Regular oil has particles of all sizes. Smaller particles burn up at lower temps than larger ones. This makes the oil go black and they leave deposits. These deposits will then build up in the joints. When you put in synthetic, these deposits start to wear away and the engine starts to clean itself. When this happens, you spring leaks. Our motors (LT-1, LT-4) were designed to run on true synthetic oil. The other stuff will kill the life of the motor as our oil temps are much higher and will fry ordinary oil. The castrol is crap to as it is not a true synthetic as the mobil 1. It may work in other motors better but not in ours. Insist on 100% synthetic. My oil with 3000 miles on it looks like wesson oil and my valve springs are as clean as day one. Look at 94Glock's headers and see the difference. If you get a new car, anyone, start with Mobil 1. If you have a used car, non LT-1/4 use what the prior owner was using. LT1/4 that the owner wasn't using 100%synthetic oil, run the other way and stay away.
92TripleBlack :cheers:

FastZR1

Well I run 15W-50 in my LT5.
But my next question.... I bought a brand new truck in July. Dealer gave me 3 free oil changes. I have used two already. Once my third one is gone, I'll change the oil. But I was planning on putting Mobile 1 in the truck too.
Some guys tell me I'm wasting my money. But if Mobile 1 works so good in vettes, why not my truck. Wife drives the truck everyday, and in the summer it tows the vette.
Any body have a reason I shouldn't put Mobile in my truck?

ZR WON

Fast:

I was debating that very thing with my 2001 Silverado... I said heck with it and changed over to 10W30 Mobil 1. No problems so far; no leaks(it is a new truck;)), no additional oil consumption(it was broken in properly, that is, run it easy for 250miles, then beat the poopie out of it;)), have 5500 miles on the current synthetic oil and it's still a nice light brown. Going to try to stick to a 5K mile change but have already failed on the first one;)

AS84

My dads got 60k on his 99 silverado, which he bought new in 99. He's used mobil 1 since day one at 5k intervals and has no problems yet. The tranny leaks but that has nothing to do with the mobil.

jimbomill

Thanks for the info .. good advice therre at the end ...except I've already bought the car prior to knowing whether it had synthetic oil or not (it was not, apparently). Hopefully still, things will clear up :)

Barrier

I believe the myth about changing to synthetic is just that. All oil must conform to minimum standards set up by both S.A.E. and A.P.I.. Minimum not maximum standards, most if not all major oil company oils comply, incuding synthetic products. These standards were set up so you didn't get high quality engine oil one time and Wesson the next.
I switched over to synthetic in all my vehicles, from new rice burners to both sons Jeeps, my GMC motorhome ( '77 455ci) as well as the '86 Corvette. The domestic vehicles all had about 100k at the change over. No problems only advantages : cooler running, almost no burning, good oil pressure, NO LEAKS.
Barrier :)

Two_Black_03

All of the above are excellent points. All the tech data I've read regarding the differences between synthetic and standard oil have to do with the heat handling characteristics. The synthetic can withstand high heat (as in hot running Corvette engines) without breaking down as much as the standard oil. The one issue that is usually debated is can I increase my change interval with the use of synthetic. The most published answer is that even though the synthetic doesn't break down, it still gathers impurities from wear. Therefore, it still must be changed on the 3K mile interval.
There are also reports on which oil is best (don't remember where I read them) which say that Mobil 1 and Amsoil are the best for temperature handling, with the rest relatively better than standard oil, but nowhere close to the 2 front runners.

jimbomill

Again, I'm not sure which standard is getting "debunked". Standards are set up for repeatability and for commonality, mostly. It's specifications of each product that help raise/set performance.
As for the leakage hypothesis, I had no oil leak on my just-acquired '92 vert. I had some engine work done, still no oil leak. The next day I had the oil work done (engine and rear) and that evening, I had the oil leak. I still do not know exactly why, but the verifiable data, in my case, supports the leakage "myth".

KYVette90

I use 10W30 Mobile 1 in my 90 with over 149,000 miles. No leaks and no problems. The valves and springs still look very clean.

Rick93Z07

Polo,

If your oil is gathering significant metallic content due to wear, you are not running Mobil 1 or equivalent. Acids and carbon particulate content from blowby is the primary buildup. You do not need to change synthetic every 3K on normally aspirated applications. Abused, blackened synthetic will usually provide better frictional wear protection than fresh dino...unless the motor is worn or in a poor state of tune and has excessive blowby. Temperature withstand is only one of many advantages.