I always wondered why you can't switch back. Any answers?

 

I'm curious as well.

 

I have never heard anything like that, as far a I know you can switch them back and forth or even mix them. Not that you would really want to mix them.

 

According to Exxon Mobil you can mix them.
I found this through a google search:
In all lies is a grain of truth. Early in the days of synthetic, the compounds in the oil had different effects on the internal seals of an engine. Petroleum contained distillates that caused the engine seals to expand or "swell". The seals would wear to the correct tolerance for that component and everything would be fine, until the owner switched to synthetic oil . Synthetics did not contain the distillates and the seals would return or "shrink" back to their original size.
This caused sometimes incredible oil leakage issues. An interesting side bar is the invent of several "stop leak additives" to battle these problems. The primary component of these was and still is today.... Petroleum Distillate
If an engine had synthetic oil in it from the beginning and for the majority of its existence, the seals would not swell and wear until the owner switched to conventional oil. Once the switch was made, you could never go back due to the extended wear to the motor.
Both synthetic and conventional oils are "engineered" today making them very similar in detergent and distillate levels, so switching is not so much of an issue anymore.

 

I'veread the same thing as cracker in a magazine before. I used to be a lube technician at one of them minute lube places and the had been doing it for more than 20 years and he always told me that he would kick me in the nuts if I ever used synthetic oil. with 20 years of experience he's seen almost everything, he doesn't believe in syn. because he has loyal customers that have over 300,000kms on their originalengines. He believes in a good filter and regular maintenance. I personally useAmsoil in my 97', I plan to keep this truck till the end so I'm not going to spare any expense but for the average person syn. will not pay off. The average person gets a new vehicle every 3 years so paying double for your oil change isn't financially benefitial. This is just my opinion, I use regular oil in my other vehicles cause I don't expect to keep them for more than 2 years but the vehicles that I will plan to keep will be getting the special treatment of Synthetic.

 

All of you should go to www.bobistheoilguy.com. Lots of info.

 

Wow ...a site for motor oil. Another site to read to **** my wife off. lol

 

i went with royal purple yesterday... i couldn't find any amsoil, how much price difference is there between the two?

 

i just cjanged the oil last week, i put in royal purple with the new engine, and for the first oil change (1500 miles) the royal purple looked like regular used up motor oil coming out, but this time im going with mobil1, so we will see how it goes. Also, there are 7 zerks to the front end of a newer chevy, upper and lower ball joints, both ends of the steering arms, and the pitman arm above ererything, tough one to get to,so id recommend turning the wheel all the way to the right for clearance issues.

 

It's a very informative site. Of course it doesn't say what the "best" oil is, unless it's the 267 stuff that I have never heard of. Anyone else?