Originally Posted by Deontologist
... should I consider changing the oil just before the trip? ... What do you think?
I am presuming that there's nothing wrong with the engine or you would have stated as such. Therefore, here's what I think.
I think 5900 miles (your 5500 + another 400) is a pitiful waste of a syn lube.
Should you change the oil before the trip? No.
Should you change it after the trip? No - not for another 7-9k miles or so. But that's going to make your head explode, so let's compromise.
Conventional oils in most applications can easily go 10k miles. Syns should be able to go far past that. There are SAE studies, and my "normalcy" study, that show wear rates trend downward for nearly every type/brand of engine out to 15k miles, no matter what lube/filter is used. Wear rates do not go up as most folks suspect until well after 15k miles of oil/filter use. Despite all the "it's cheap insurance" dogma prevalent here and elsewhere, there's good data from many sources to show my recommendation is sane.
If you simply cannot bring yourself to extend out past 10k miles, then quit using syns; what you're doing is a waste of money. It is not "cheap insurance" to quit using a product that has at least 50% of it's viable lifespan still available.
- Would you change a quality Michelin tire after only 30k miles of use, because it's "cheap insurance" to get rid of it in favor of a new tire?
- Would you toss out a beer after only consuming half the bottle, for it's "cheap insurance" to just get another one?
- Would you buy a new battery for your car, after only two years of using the current one, because it's "cheap insurance"?
If you answer no to these, then why are you wasting oil???
I encourage you to start a UOA program, if you have not already. Convince yourself with the data, not the BITOG supposition of uninformed opinions.
If you have a UOA series already, then what's it telling you? What are your results?
Here's my advice:
1) don't change the oil yet; go on the trip.
2) when you get back, go ahead and change the oil (you know that's what you're going to do anyway, so let's not pretend otherwise). At the OFCI, get a UOA.
3) after the UOA data comes back, and it's very likely shows there was tons of life left in the lube, then run your next OFCI to 7.5k miles, and then UOA again.
4) after that next one comes back good (and it will) then extend to 10k miles.
5) do this until you get to a reasonable condemnation limit not based on panic or ridicule, but on real data wear rates.
And I'm willing to put my money where my mouth is! I'll offer to pay for the UOA and the OFCI, if the UOA data shows that doubling your OFCI out to 12k miles is unsafe, as determined by macro data statistical analysis (defined as going outside the bounds of the stdev limits for the wear rates of the common metals; Fe, Al, Pb, Cu). Your engine must be healthy; no coolant, fuel or air ingestion issues. You must share your UOA data here on BITOG. You must drive normally; no hanky panky to bias the results; no additives or bizarre stuff. Just your normal routines with the typical products as described. If I'm right, you have to double your OFCI and pay for the UOA and OFCI. If I'm wrong, I pay for the UOA and also the OFCI. You are allowed to pick a member here that is trustworthy, and I'll send a check to be held in escrow until the results come back.
Man up, trust the real world data, and live outside your comfort zone by making an informed decision, not one based on mythology and rhetoric.
Or not ... it's up to you.