I was researching this question online outside of this forum and it seems as though Amsoil comes out ahead of the game. Can I get first hand testimonials from users of these oils - more points for anyone who has tried both. It would also be interesting to know what oil change frequency people are using. I plan to change the (UNKNOWN) oil in my dealer serviced 2003 Ram 1500 hemi with 82,000 miles on it,
Steve

 

i just switched my oil from just standard oil to the royal purple, and the engine seems to be running alot smoother then it was. ive gone almost 3000 miles on the royal purple, i used to have a slight ticking sound and now its gone.

 

I've been using Amsoil for the past 10k miles, engine ran smoother and got better fuel economy, about 1 mpg more. Changed it at 6,500 miles even though I was told I didn't need to until 8k. At 6500 the oil was cleaner than the conventional I was using when I changed it at 3k miles. There's people here who swear by both Amsoil and RP, personally I haven't used RP (yet) and couldn't tell you which is better, but I highly doubt you could go wrong with either one.

 

I recently made the switch from Mobil 1 to RP with similar results to Pyro. I won't speculate as to which is better, they are both among the elite oils. It's just easier for me to walk into the auto parts store to pick up the RP when I want to...

 

Ive been running AMSoil for about 10k now in the ram, and in my last rig. It came out cleaner at 8k than my last oil did at 3k.
I am a big fan. I was going to try mobil, but think i will just set up a preferred cust acct with amsoil again and keep ordering it.

I have not tried RP, so i can't say anything about it. Other than as said, i dont think you can go wrong with either.

 

both oils are great, but always, always, always change your oil at 3,000 miles, don't go over that no matter what any paper or person tells you

 

+1. If going Amsoil, become a preffered customer, well worth the $10


-1. I have seen no data or statistical support for this whatsoever. Higher grade synthetics do not deteriorate like dino oil. The only thing still in question is the filter, so change the filter every 3k or 6k depending on the quality of the filter. Maybe he means so you do a regular inspection??

 

if you want the best filter buy a hastings or baldwin filter. fram, wix, purolater filters are well crap. all oils deteriorate in harsh environments, I am a professional mechanic and former engine builder, I've seen what any and all oils end up like after 3,000 miles and as a man of the trade, I strongly suggest not to go over 3,000 miles for the sake of your engine. I'm just giving some experienced advice is all

 

Some great feedback here guys - many thanks. I spend a lot of time on a forum for Factory Five Cobras and there was a lot of info on oil filters. Napa Gold came out best by a wide margin. I wouldnt use anything else on my Cobra or any of my cars.
Given the close ratings for Amsoil and RP, I am inclined to go with RP for the reason mentioned here. I can get it from my local Autozone
Steve

 

i use royal purple and its great