Purpl, I'm actually back to using wix filters. Been good so far. I'm not real sure if it was just the Chevy's filter design, or just a fluke on Wix's part.

 

i had a guy who deals amsoil tell me some things and ive seen it too..


ive seen a couple of rams witharound 600,000 miles on them running amsoil filteration systems and amsoil they run the oil for a full year and send it out for testing every 5000-10,000 miles generally they get about 25,000 miles per a change.. theis weredilevery vehicles for parts stores and such..


i had a heavily built harley sportster making about 101 whp and i went from schaffer syn to amsoil and noticed the bike ran cooler by about 18 degrees and the valve train noise quited down alot to.....


in so saying all oil if changed at 3000 will perform the same they have to.. that all need to met the same criteria to meet or exceede oem applicaions... hens a lil seal on that back of oil bottles that says somthing like api certified or somthing.... syn is held to a higher tolerence and their for meets different criteria.... if it was me stick with the amsoil use a good wix filter and change it around 6000 miles syn has the ability to absorb acids and nuteralize them and coat metals with a thin film for better protection on start up....

 

I stay away from Amsoil for one reason, and one reason only.

Over time, Amsoil will change in vicosity. Not a good thing. There have been a few tests that have proven this. One test that I recall started off with a 5W-30 oil, and at the end of their testing, it lab tested as a 15W-40. To me, that's not a good change on the bearings. It reminds me of a friend that built a 502 awhile back. He had just got done breaking this motor in, and when he did the oil change, he didn't pay attention to the oil he was putting in. He put 3 quarts of 10W-30 in, and then the rest was a straight 50 weight. When the oil pump shot the straight weight in, it literally pushed the bearings out.
Now, will amsoil cause the same thing? No. I just have a hard time using an oil that's going to change viscosity over time. Consider, Usually when you change to a heavier oil, you really shouldn't go back down again.

Another thing that's going to hurt amsoil in the long run is the MDS motors. They are extremely picky on what weight of oil they can and can not run. IIRC, The 5.7 and 6.1 HEMI will only run on 5w-20. Any other weight can actually make the MDS not kick in, or kick in at in opportune times.

 

I am curious as to who produced these reports that you mentioned Laraime1997. Are these reports available on the web? I would be interested in reading them. I use Amsoil 5W30 with a NAPA Gold filter and change mine every 7000 miles. I have over 162,000 miles on mine and when I changed my intake out to a M1 the inside of the engine was clean. No sludge build up. I would probably go longer with oil changes if I wanted to take my time to send off samples for testing. But the way I have been doing it seems to work fine for me. I do about 2-1/2 oil changes a year since I put on about 17000 miles a year on mine. I travel several 1300 mile trips between Florida and North Carolina each year in the fall and early winter. Getting ready to start those trips in 2 weeks. I have run synthetics since the first oil change.

 

^ http://neptune.spacebears.com/cars/stories/amsoil.html

It's not that big of deal in our motors, but like I stated, not good for a motor equipped with MDS.

 

what the heck is mds?

 

Multi Displacement System

Basically, it's a Valve timing controlled system that allows the motor to disable 4 of the 8 cylinders to improve fuel economy. Nice idea in a light car, but not in a 4000#+ truck.

 

Multi Displacement System or something like that. It shuts off half of the cylinders when not needed.

I say stick with AMSOIL. My dad switched his M11 Cummins in his old Freightshaker from Delo400 to Amsoil and I could feel the difference from the passenger seat, smoother, quieter and would run MUCH farther up the grades without the fan kicking on.

Also switched over my buddies 1st gen CTD and noticed similar results, also gained 0.5-1MPG.