Very good imput, going to stick with synthetic from now on just making sure i didnt hurt anything for the 6 months i had conv. oil in there. i think my blend is 5 20 syn pennzoil.

so are saying penn. is better than the rest.

 

You can switch back and forth between synthetic and conventional as much as you want. They blend with no problem (hence some brands sell "blended"), and you won't cause a problem by topping synthetic off with conventional in a pinch.

The misconception that synthetics could cause leaks in older engines has to do with the early introduction of synthetics back in the '80's, because they had much better detergents, which when put into an old engine with leaks that were plugged up with sludge, started to drop oil as a result of suddenly being clean. The nice thing about synthetics are that they don't build acids like the conventional mineral oils, and don't need to be changed near as often, and shouldn't be changed as often. All oils start out with an alkaline PH, and over timethe PH changes to an acid. Changing synthetics as often as conventional (3,000-3,500miles) will hold the oil at too high an alkaline PH. I run my Mobile 1 to 15,000 miles with no problem, you may want to change the filter sometime in that period if you're worried (I don't because of the filters I use), but you should be running it well over the 3,000 mile mark. Also, I buy the good Wix filters at the local auto parts store (Bumper to Bumper, Carquest, etc.), and I don't think you can get them atAutozone or Advanced Auto or whatever other generic "cheap" discount auto parts places there may be out there.

My daily driversaverage 35-40,000 miles a year, and the least amount of miles I've put on any one ofthem is 167,000. I've had no engine problems with these last 3 cars since I started using synthetic, and have hadabsolutely no dirt sludge build-up. If you got the choice, synthetic is the way to go-zero wear.By the way,a new car you'll want to run conventional for at least the first 10,000 miles to get a proper break-in, then switch to the synthetic.

RichS

 

Synthetic in all my car except my beater. I run Mobil 1 Extended Performance10w-30. I change my oil in my stang once a year. I have only put an average of 1300 miles each summer for the past 3 years. I would never run 5w-20 in any of my cars even if it called for it. 5w-30 is the absolute thinnest you will ever get me to put in my car!

As far as the dealerships only putting 5quarts in as stated earlier, they put what is needed 6qts. They simply have a set price for oil changes and set the max at 5qts. They charge you extra for the 1 qt. No oil change place especially a dealership would short change an engine of oil.

Synthetic oils and conventional oils of the same weight will mix unnoticeably. You just cannot mix a 10w-30 weight oil with 5w-20w as they do not mix ever! Not saying they are like oil and water butthis can cause irratic readings on your oil pressure guage.
Going back and forth has no effect on anything as long as you change your oil frequently.
Aslo, no oil additives!!! Bad for your oil galley holes and oil pump as thick additives will settle and gum up.