So I had to try it. About this time last year I put AMSOIL 0w-30 signature series oil and their EA filter. Here is what is expected:
Service Life
AMSOIL Signature Series 0W-30 Synthetic Motor Oil is recommended for extended drain intervals in unmodified(1), mechanically sound(2) gasoline fueled vehicles as follows:
• Normal Service(3) – Up to 35,000 miles or one year, whichever comes first.
• Severe Service(4) – Up to 17,500 miles or one year, whichever comes first.
• Replace AMSOIL Ea oil filter at the time of oil change up to 25,000 miles or one year, whichever comes first (other brands at standard OEM* intervals).
• In all non-gasoline fueled vehicle applications, extend the oil change interval according to oil analysis or follow the OEM* drain interval.
I used my Jeep as a Daily Driver and to plow (maybe 5 storms at 3 hours a storm) so I would consider it to be severe duty. I only put on 10,000miles over the course of the year. So I was well within the specs of what is to be expected. My engine is at 90,000 now and is very well maintained.
My findings are as follows:
The oil continually stayed clean as I could still read the dipstick clearly. I never had to top off the oil through the course of the year as it never went below normal. At the end of its life it felt a lot thinner between my fingers as it once did. My oil pressure at idle would float around 40-45.
I now replaced the oil with the same 0w-30 signature series oil as I had 5 quarts left. I did not replace the filter with an AMSOIL filter as I was not going to renew my membership with them just to get a filter nor pay the non member price. I replaced the filter with a BOSCH Distance Plus. The old oil looked like conventional oil after 3000 miles. There was no foam or frothing like conventional oil that has not been changed in 5000 miles or higher (oil is breaking down and less viscose when it is frothy).
After replacing oil and driving I noticed a decrease in the tone of the exhaust immediately. As I was driving I could feel a slight power increase. My idle oil pressure floated around 55-60 now and raised almost to 80 when accelerating and holding at or above 2200 or so rpms.
Needless to say, my Jeep is much happier now. I am planning on finding a kit or a lab that will test the old oil. If anyone knows of either please let me know. I will be pulling the valve cover soon to have a visual. At the same time I started this I also had the head/valves/springs completely decreased by a machine shop. I will NEVER go this long with out an oil change again regardless of what any company claims. That is only my opinion and these are my findings. I hope this helps anyone's curiosities on the subject.
