Switch from conventional to synthetic oil

We bought the 2001 Z28 used and are going to change the oil this weekend. We used Mobil 1 from the start with the 2002 SS. But since we bought the 2001 we don’t know if you can use synthetic oil after conventional oil has been used. Can or would it make a difference switching from conventional to synthetic oil. If it would make a difference what synthetic oil is better to use: Mobil 1 or Royal Purple? Thank you for any comments and advice!

I bought my 98 z with 36k on it and immediately went to mobil 1 synthetic and have not looked back. It is very good and reliable. You may also want to change the differential gear oil and fuel filter as part of the maintenance you are going to do. I did and it made a noticeable difference in the way the car ran/mileage.

Might not want to use the popular mobil 1 5w30. It is on the thin side of 30 and shows more wear than better oils. Read patman's posts on ls1tech.com or bobistheoilguy.com. He also had disappointing results with royal p. Best oil is the german castrol syth, but that is hard to find. A good alternative that is easy to find is 5w40 mobil 1 truck & suv in the 5 qt container from wally world. I buy an extra quart and use the long k&n filter with it. The m1 t&suv has been getting great reviews, like this one:

http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=3;t=002141

Based on test results like that, I plan on running it for at least 5k/miles, maybe more.

Sure, go with the synthetic, try Royal Purple, great stuff, Jeg's and Summit sells it, and possibly your local Pep Boys.

SteveC :)

You may find you'll use oil with synth when you don't with conventional. I did.

Best oil is the german castrol syth, but that is hard to find.

Where do you get the German castrol sythetic? Is it that much better than the castrol synthetic you'd find at any autoparts store? My TA has 115k miles on it, and i changed to synthetic for like one oil change but i noticed the oil in my pcv started looking kinda milky and didn't like that sh*t so went back to synthetic blend castrol after about 1k miles like i had in there before.

Supposedly at Autozone, but I've looked in a few in my town and never found it. It gives better wear numbers than any other oil. But we're talking about the best oil in a group of very good oils. Not like this is the only good one and the others are scrubs. But as long as you are springing for synth, might as well use the best you can get your hands on. I can't find GC, so I use the best I can buy, which is the M1 T&SUV.

http://web.camaross.com/forums/showthread.php?t=238136&highlight=german+castrol

As far as the milky appearance, I've read on BITOG that synth behaves like a detergent oil, so it can clean out old deposits from dyno oil which might open up leak pathways. Might also have caused the effect you observed. I switched to synth shortly after I bought my 98 w/47k on it, 1st Vavoline, then the M1 T&SUV, and noticed nothing weird.

Synthetic oil is better for an engine whether it's new or old. I bought my z28 with 65k miles and the next day drained the oil and put mobil 1 in it.

the m1 t&suv is 5w40 right? Wouldn't a high milage motor like mine (115k) be better off with like a 10w40? Something a little thicker since my motor has more wear?

I run redline in my 2000 SS. I used to run Mobil1 and still think its a great oil but now that my car isnt my daily, i run redline in it.... great oil. My friend has tested many oils including mobil1, royal purple, and redline, he sends samples off to get tested and the redline is obviously the best... just my opinion

the m1 t&suv is 5w40 right? Wouldn't a high milage motor like mine (115k) be better off with like a 10w40? Something a little thicker since my motor has more wear?

Yeah, it's a 5w40. My motor goes to almost 60 when it's cold with the 5w. I use the long K&N which is low restriction and doesn't drop pressure like more restrictive filters.

115k isn't a huge amount of miles. I used to use 10w40 dino in my last daily driver with ~ 100k and it held good pressure hot. Hot is where pressure will drop off if the motor has a lot of wear. Worn out motors can hold > 40 cold, but will drop to ~5 or less at hot idle. As long as pressure is good hot, no reason to go thicker.

I have an L03 305 TBI with 300K on it. Synthetic since 100k. Still going...

I looked at the notes left by the previous owner of my 98z28, he used synthetic.I now use german Castrol Syntec 0w30. Oil pressure went up, dunno about consumption since I did the oil change a few weeks before she went into storage. Seems oil level is still around I remember it since I managed at least 1k miles before storing it.

where'd you find the german castrol? Autozone's got all made in u.s.a.

Amsoil 0W30 works great in my SS (105,000 miles), my oil pressure went up and cold start up is much smoother now.

Amsoil 0W30 works great in my SS (105,000 miles), my oil pressure went up and cold start up is much smoother now.


I'll second the Amsoil.

Hard part may be finding a dealer in your area.

Frat

where'd you find the german castrol? Autozone's got all made in u.s.a.

Murrays usually has a huge sellection of oils. You could try to find it there.



And to answer the original question: You will be fine changing from regular to synthetic. Why would the cam manufactures tell you to use regular oil during an engine break in and then to switch to synthetic if it wasn't okay? You'll be fine...

Check out this site, very informative. I'm not trying to push anything, but shows good comparisons.

George (the owner of the site) is a straight shooter and is glad to answer questions!

http://oilhelp.com/

Been using Amsoil in my rides ever since.

Allen