Originally Posted by 05silvertacoma
I switched to Amsoil xtended life oil because (1) it was on sale at a former retailer (GI Joe's) and (2) for lower rpm on cold starting. With Dino (traditional oil) the engine went to 2200 rms, with the synthetic-it DROPPED to 1800 rpm. It's common info that most of the wear is on cold start, so Less rpm=Less wear! i'M very HAPPY WITH THE AMSOIL Extended Life and had oil anaylsis done after my 1st & 2nd changes after switching. Everything was fine so I xtended the change intervals to 10 and than 15k. No problems and the engine runs great and smooth. The oil stays much cleaner also, with the dino, it was dirty at 1500 miles. On the Amsoil, the color when I change it is slightly darker than what I put in. You can't go wrong with any ester base oil. I'm told Royal Purple and RedLine are also very good, Use what you want-But get the used synthetic anaylized so you know whats happening in your engine. You'll know if the bearings or other metal is deteriorating and if any fuel or coolant is in your oil. Also use a QUALITY oil filter. There's a site where a guy bought numerous brands, opened them up and shared the info (w/some pic's) Lots of good info and his observations there. Good Luck!
The idle speed, whether hot or cold, is computer controlled and it doesn't know you have Amsoil in it so if it really changed I'd be highly concerned. Most of the color change of an oil comes from the contaminates it collects from the engine. An oil that stays clean could be doing so because it's leaving contaminates in the engine instead of carrying them, I've seen this. I'm not trying to say Amsoil is bad, just pointing out that your only two points for it are highly debatable. I had two customers that started using the extended drain amsoil (25K intervals) and one developed a serious engine problem about 50K miles into it. I don't have any evidence to show it was because of the oil as he had the repair done by someone else, but they told him the engine was really dirty and he should change his oil more often. I do believe Amsoil to be excellent, but their suggested drain intervals may be a little to long in some cases. It probably lubricates fine at the long drain, but may not be able to control and carry the contaminants as well as a cheaper oil at short intervals.
Back around '93 I bought a '89 Nissan pickup that had 42K on the factory oil and it was still running, even tho it was down to under 2 qts. left, but it was making noise. The drain plug and oil filter were still sealed in engine paint and I had to break the filler cap loose with a big pair of channel locks so there's no doubt it hadn't been serviced. I refilled it and the engine ran fine. It took several oil changes before it stopped turning the oil black quickly, but then seemed to be back to normal. I drove it for over two years and never had an issue. At my last job one of the employes was driving a '98 mustang with 40k on the factory oil, again no signs of a problem. All it proves is that any oil can go a long time without showing obvious signs of a problem, but I can't imagine there was no damage caused by it.