Re: Thoughts on new rotella t6 synthetic oil?
Rotella is a diesel-spec oil, meaning among other things it has more zinc in it that flat tappet lifters in older engines like. The govt required zinc content to be lessened because it fouls catalytic converters when the engine burns oil. With roller lifters the lack of zinc is not a problem. Like jps4jeep, I would not recommend a full synthetic on an older engine with a lot of miles. Assuming you're asking about using it in your listed Jeep with an AMC 360, I would recommend either plain ol' Rotella 15w-40 or Rotella T-5 10w-30 synthetic blend. I just changed out the T-5 I had in our Jeep for the first time and sent a sample out for a used oil analysis but haven't got the results back yet. The full synthetic Rotella is a 5w-40 which IMO would be a little thin for an older engine.
Full syns and diesel-spec oils will clean out the inside of your motor, not necessarily a bad thing, but when the crud dissolves then oil will get by some places that it didn't get by before. I had been using regular Pennzoil in the Jeep changed every 3000 miles and it burned some (has 156k on it) but with the Rotella I added 3.5 quarts over 3000 miles to an engine only holds 4 quarts. It does not leak, but then neither does it smoke. Right now I have Valvoline Max Life 10w-30 in it and I will get a UOA after 3000 miles again and go with whatever oil it likes better. In older engines high mileage oils are a good choice (even if it does not have high mileage) also because they have slightly more zinc than regular oils.
Steeler Nation does not have to travel. We're already there.
'97 TJ 4-banger restoration project. My daughter's rig but I buy stuff and tinker with it.