Synthetic oil change intervals

[StroktWJ]

Before I get into the subject, I choose to post this thread on this board because of all the forums I am or have been a member of JeepStokers.com has the best, smartest group of guys that are most courteous.

Ok... I know most of you are probably on the same page as I am with the 5K mark on synthetic oil change/filter intervals... I have been hanging out on this other board while I rebuild the engine in my 300M to get some part ideas.. Anyway guys were saying they did an independent test with "Black Stone Labs?" and that you should change the filter at 5K and run the oil till 10K.

Just wanted to get some opinions.

[apwatson50]

I'm running rotella 5w40 and had one test done at ~5300 miles, everything looked pretty good, so i'm going to stick with ~6k mile OCI.

[1bolt]

I don't think it's unrealistic to try and get over 5 or 6k but I wouldn't do 10k on the recommendation of any small scale test. If they took 100 jeeps and 99 of them showed good used oil analysis' all the way to 10k on the same synthetic oil, and one jeep had a poor UOA (Used Oil Analysis)I would wonder if my Jeep was a 1-100 or a 99 out of 100... So I would only go over 6,000 miles with a UOA around 5,500 or 6,000 if it looked good I would check at 10k and if that looked okay I would change the oil and repeat the process once more, to confirm and then I'd feel save.

In other words even if the "test" involved several hundred or thousand Jeeps and all showed good UOA's at an extended change intervals like 10k miles you STILL don't know if you have a leaky injector, or a coolant leak getting into the oil slowly... If you are a little high on wear metals or gasoline in the oil or coolant in the oil at 5,000 miles you might be damaging your mains by 8,000 miles... So without testing your oil at least a few times and occasionally thereafter you could be doing serious harm without knowing it.

So If you go long intervals test... if you don't want to spend 25 bucks occasionally to double your oil change interval (OCI) then go more conservative (6k is fine in my book without testing) I still do the odd UOA just to check.

[laxplayermjd]

if you want some piece of mind most bmw oil change intervals are 12-19k miles. Although i change mine more often.
We use BMW 5w30 synthetic,, we think its just castrol because thats what bmw recommends