I am starting this thread from a previous one that started to get into the oil issue again. I would like to discuss synthetic versus dyno, intervals, high end oils and anything else associated with.
Couple of questions I have to start it off:
1. I have heard that once you use synthetic you should not go back to conventional. Does anyone know of any scientific reason to this?
2. I used Royal Purple once before and I just could not bring myself to spending that much money on oil again. And I know Amsoil is even more. Maybe it is me, but I just don't trust leaving oil in a vehicle for as long as they recommend. I buy the Motorcraft 5w20 at Walmart for about $2.25/qt. With the oil filter I am out the door for less than $30. Change the oil every 4-5000 miles and this is $90/year in oil changes.
3. I have a hard time removing the oil filter on the 5.4l (2004 FX4). Anyone else run into this and any ideas?

 

I did a lot of research on the conventional oil vs synthetic question and I was about to go crazy. Even if you go synthetic, you do not know what brand is a true synthetic since there are different groups of base stocks PAO III,IV,V. Groups IV and V being the best. From what I read there are few true synthetic left like amsoil, royal purple, redline and German castrol. Read mobil vs castrol lawsuit, castrol won and now most oil makers use the cheaper group III for their synthetic oil, even mobil. Most of what you find at retail stores shelves are group III synthetics. Remember synthetic oil means modified oil. Some brands say you can go 12-24k between oil changes, others change oil filter in between oil changes but most people recommend 5-7k miles. So, I decided to buy whatever was on sale at walmart. I got 6 quarts of castrol syntec and a motorcraft filter for 32 dollars.
On your Questions,
1. Yes, most brands say you can go back to conventional after using synthetic.
2. I'm using castrol syntec with motorcraft oil filter.
3. I turn wheels all the way to the left to have more room while removing oil filter.

 

Thanks for the great answer. Any reason for using Castrol Syntec? Just curious.

 

I found a lot of good reviews on castrol gtx. I've been using castrol high mileage in my wife's infiniti and really like it. I never had any problems using motorcraft in my f150 but decided to try something else.

 

I always used to use Mobil 1 and changed at 5000 miles. On my new truck I'm going to use the Ford 5w-20 and a Wix filter. Check out this site: http://www.bobistheoilguy.com/

Spend a couple of hours there and you may be buying Supertech from Wal-Mart!

Also, check out http://www.fleetfilter.com for Wix filters.

Joe