Brisk20

I was wondering what the true difference between the semi synthetic and synthetic oils are?? Is is worth the upgrade? Also I heard somewhere that Mobil1 oil is not synthetic but semi synthetic?? does anything have to be done b4 changing to true synthetic such as an engine flush???

imported_cet_civic

Difference: Motor oils are made up of base oils and additives. Fully synthetic motor oils contain high-performance fluids. Semi-synthetic oils (also called "blends") usually use a small percentage of high-performance fluids in combination with conventional oil.

If you want to run these concentrated high performance fluids, and can afford it than, yes its worth the switch. I personally run the "blends", and as long as you change the oil on a regular intervals you should be fine. And as far as I know you dont need to flush out anything in your motor to make the switch. Just do a complete oil/filter change, and your good to go.

Someone may have some more detailed info for yah, like bbarb!

my $0.02

bbarbulo

iTrader: (2)

naw, you got it right on... there is base stock of oil (carrier) and additives (like detergents, friction modifiers, etc...) semi-synth is a cheaper alternative, but the base stock will still break down just like regular oil.

As for a flush, well, really you shouldn't have to, but if you got an engine that's prone to sludge buildup (perfect example is a Chrysler Intrepid engine) you should. Even if you have an older engine where service history is unknown it would be a good idea. I've heard very good things about Marvel Mystery Oil being added right before a change, run it for a few hundred kms, then dump and change again. Doing this a few times is a gentle way to cleanse your oil passages of sludge deposits and restore oil pump efficiency.

Like I said before, I use Mobil 1 and change it frequently.... it's more expensive, but hopefully superior lubriaction will make my engine run for a significant period of time w/o the need for internal work.

Buff 'n Stuff

No flush required. Flushes are good when the motor has not had regular oil changes done at proper intervals, or the oil is obviously contaminated. Changing back and forth from conventional to synthetic or semi-synthetic oil does not require an engine flush. In fact, conventional oil may be used to top up an engine which contains synthetic if need be. The oils mix.