mobil 1 or...

royal purple or amsoil? wich one should i switch to? V6 3.4 taco 4500 miles. wich one is better and what oil filter would be a good match with that oil? i know this is brought up often but now its my turn :) thanks.

More opinions than you wanted:

http://theoildrop.server101.com/cgi/ultimatebb.cgi?

My opinion - Oil? You'll never notice the difference in oil between those brands.

Filter?
http://www.oilfilterstudy.com/

so i will go with amsoil oil and filter after all. thanks Brian R. but you think i should also change my auto trans. fluid im at 4459 miles?(to take out the orig.) if i do all this my taco will be a AMSOIL FLUID TACO:) mucho $$$ oh yeah is it normal to have a small whistling sound under my truck by the tranny i heard it tonight when i just let it roll along just idling and i parked and checked it only does it in drive not reverse or neutral (when the rpms are lower in drive than in park or neutral but it doesnt do it in reverse??? ) and all my fluids are fine. thanks

For the transmission, change at the recommended interval. The whistle is probably a vacuum leak. Check hoses.

thanks again brian

royal purple or amsoil? wich one should i switch to? V6 3.4 taco 4500 miles. wich one is better and what oil filter would be a good match with that oil? i know this is brought up often but now its my turn :) thanks.

I would definately stick with the Amsoil. Its the best see http://www.synthetic-lubricants.com/amsoil_vs_mobil_1.htm. You can use the Amsoil SDF-57 Filter cange at 12,500 miles or 6 months.

Those study results are questionable. It was done by AMSOIL - What result do you expect?

What happened in the testing they didn't report?

Those study results are questionable. It was done by AMSOIL - What result do you expect?

What happened in the testing they didn't report?

Ah another unbeliever!!! I used to be one too. Imagine if they reported the test results in a fraudulent manner. They would be sued. How long can you keep your oil in for? Even OEM manufacturers are increasing drain intervals with plain old petroleum. Just because Amsoil reported the results doesn't make them biased. They use outside testing facilities ( CTC Analytical Services) to preform the actual test.

And just maybe they reported the results they want you to see. No one can sue them because the complete report results are proprietary and you'll never see them or make them publish anything they don't want to. Omitting information is not fraud.

Even if they publish the complete test results, they know what additives they have high levels of and can request testing on those attributes that are improved by those additives and no others. There are alot of testing they could have requested and didn't publish the results of that? Why not? Are they afraid of the results? or do they know the results and the results are worse or not significantly different than their comparitor?

You better get sceptical or you will be taken in by anyone who wants to take you. It takes more than some hired test results for me to believe it when any company says that their stuff is the best. Like I said, what do you expect them to say?

My family owns a large refrigerated trucking company and I have talked my father into running Amsoil in one of the new Freightliners and then tear it down after 500,000 miles and compare with conventional oil. I will post results at a later date. This is as independent as it will get. ONLY after my own tests and seeing firsthand will I ever extend my change intervals and/or oil!

You will still have to answer the question: Was one of the two engines better than the other initially or driven differently?

Maybe one of the engines was assembled with better bearing clearances, tighter rings, harder journals/cam lobes, etc. Were the engines driven with the same care?

A driver who consistently makes the engine wind higher or lugs it more may make the engine look different than one treated with care, everything else being equal.

Judge your results with care.

Also, the discussion above compared Mobil 1 with AMSOIL. That is an even tougher comparison.

i have been using castrol gtx or gpx whatever, 5w30
is that too thin, and should i be using 10w30 2.7 liter 131,000 miles