I'm going to be changing my oil for the first time since I bought my camaro. It's 91 z28 5.7 with 124k miles. Is there any easy way to tell whether it's been using regular oil or synthetic oil?

If I find that it is using regular oil, what would be the advantages of switching to synthetic and what extra steps would I have to take to make the switch.

If it is using synthetic, are there any certain types or brands I should be using? Do I have to worry about matching the type/brand that is already in there?

 

No way to tell, no need to match it.
Just pick a nice synthetic and pour it in. Mobil 1 is popular on here.

 

Check the last "service" tag if there is one. Likely places are the door, windshield, underhood.

JamesC

 

Among some. . .

By "nice", that means no Penzoil, Quaker State, Valvoline, etc. synthetics. You're better off using Wal-Mart synthetic than theirs.

In no particular order, Mobil 1, AMSOIL, Royal Purple, Red Line are fine.

 

Somebody told me that walmart synth is actually made by mobil. Is that true?

 

Always the diplomat, five7 (but we know what you truly believe)

JamesC

 

I disagree here, Valvoline Synpower synthetic is a great oil. At the last shop I worked for, we used it exclusively in a commercial accounts work trucks. By work trucks we were talking 2002-2004 GM 2500/3500 HD with the 6.0 and 8.1 that were gettign 150,000 miles a year pulling 8K lbs behind them. The engines would get so hot the dipstick would be completely coated in charcoal for about 7" around the exhaust manifold. The trucks would run somewhere between 5,000 and 10,000 miles between services. Oil would always come out a little dark, but all in all not that bad. MANY trucks had over 450K miles on them and were still running.

 

Whitchman, I have heard that there are labs that will "diagnose" a small sample of oil for you for not much money, search the net if you want. Recently on this site, people have posted about engine problems, mainly smoking, after switching to synthetic oil after using conventional oil. You may want to do a search on this site for that info. It was posted in the last week or so. If you want to avoid problems, have your oil checked.

 

Basically the same results you can get out of petroleum-based diesel oils.

 

So if I have conventional oil, can I just drain it and throw in synthetic as if It were any other normal oil change?

I've read that some people have problems with leaking after making the switch due to the smaller molecules in synthetic oil. Should I be worried about this? Could I cause permanent damage to the engine?

As I understand it, one of the advantages of synthetic oil is the mileage between changes. How often should I change a typical synthetic oil?

 

Depends on the maintenance it's received. If there are heavy deposits left by the oil previously used, the "good" synthetics will break that up and contaminate the oil. Not a biggie, but something you should be aware of. A good crankcase flush before putting the synthetic in will help reduce the contamination.

One method of cleaning the engine is to use conventional petroleum-based oil with one quart of synthetic for one oil change (i.e., 4 qts of regular, 1 qt synthetic), then 2 quarts of synthetic the next oil change (with 3 qts of regular), etc., until you're up to a full fill of synthetic (changing the filter each time, of course).

The "smaller molecule" part is a myth. The contaminated oil (dirty oil gets past the rings more easily) and deposit cleaning (the deposits can actually form a seal "dam") are the real reasons.

Again, only true with good PAO synthetics. Mobil 1 used to say 25k or 1 year, now they say per manufacturer's recommendation through the warranty period. AMSOIL says 7500-35k or 6 mo-1 year, depending upon the particular product and vehicle condition/use. Red Line says 7500 miles (up to 15000-18000 with mostly highway). Penzoil, Valvoline, Quaker State, Castrol, don't recommend extended drain from what I've seen or heard.