My solution to 'Change now or after my trip' ques

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pbm

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From time to time members ask "should I change my oil now or wait until after my long trip" when they are nearing the end of an OCI. I am facing the same dilemma now as I will have 4K to 4.5K on the dino in my Corolla when I leave on a 1500 to 2K mile trip.
I normally change at 5K but I've decided to extend the interval until after the trip with a few adjustments. I'm going to drain a quart and add a fresh quart before the trip to replentish additives. I'm basing this decision on the data gathered on this site...notably the '3 Mad Ponchos' study which showed that adding a quart of oil significantly improved the oil in the pan...and also the theory that used oil lubricates better than fresh oil (until the point that it begins to break down).

PS: the current oil has about 80% highway miles..

What are your thoughts on my theory?
 
I can't speak to the impact of replacing one quart of oil, but if you are going to bother going through the process of draining one quart of oil then I do wonder why you wouldn't just replace all of it while you were there? I was recently in a similar situation and had a free afternoon one weekend prior to my trip, so I just said nuts to it and changed all of the oil a little earlier than usual along with a tire rotation and the other stuff you do prior to a trip. Time is money, and a full supply of clean oil never hurt anything
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Originally Posted By: pbm
What are your thoughts on my theory?

It does make sense, although not enough for me personally to go through the trouble of draining a quart of oil. I wouldn't bother. 6K miles of hwy driving on modern API SN mineral oil is nothing. But of course this will turn into another heated hair splitting debate, as is customarily the case on BITOG.
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Using M1 0-20, I had about 8k on my Fusion this last April and I made a trip to Florida from Illinois. I put 2500 miles on the trip with no issues. Actually I have done that several times. However using dino, I would change it.
 
I hear ya..but as I'm semi retired I have plenty of time.

I would rather come back from my trip and do my 'fall' oil change then.
I also feel that the current oil (with a fresh 20-25% added) may actually lubricate better than new oil.

Before joining BITOG I thought you couldn't change your oil enough...that changing your oil every month (regardless of miles) would guarantee unlimited engine life. I now realize that the ability of oil to lubricate improves with mileage (Ford's study) up until the point that the oil starts to detiorate.
I think the goal is to determine when your oil starts degrading (through UOAs) and change just before then to insure long engine life at the most efficient use of resources. That's the theory I'm looking to discuss.
 
I had a 15 hr straight drive to Florida to do and back
Oil monitor said I had 30% oil life.
Being anal I worried over it. I came back with 30% left. Really.
Of course Honda does it at 10% at a time. It took 3 more months to get at 5% which Honda does only before 0%

Those 2500 highway miles did nothing much to the oil.

I never change oil before a trip. I change a few weeks prior or so. Fresh oil always kills my MPG.......... Always does no matter the car.
 
The used oil in the study that you are talking about was twice the interval that you are thinking of, and you are using it as a determinating point. Just run the oil to the end of the trip...If you think that study is relevent.

If you want to drain out a quart, drain the lot and be done with it.

I'd just run the oil for the trip, and change it after.
 
Originally Posted By: AirgunSavant


I never change oil before a trip. I change a few weeks prior or so. Fresh oil always kills my MPG.......... Always does no matter the car.

you are on to something.. i noticed that too. My shell helix ultra 5w40 is now at 7200km and i notice an improvement in mpg a few weeks back. I wonder if its caused by reduced viscocity of the oil shearing down to something like a 35wt ?
 
Originally Posted By: Shannow
The used oil in the study that you are talking about was twice the interval that you are thinking of, and you are using it as a determinating point. Just run the oil to the end of the trip...If you think that study is relevent.



I'm thinking that modern oils (even dino) are a lot more durable than we give them credit for. My relatives in Europe often go 18K on an OCI (admittedly on syn.) and sell their cars at 150 to 200K (to a neighbor who then drives it for years).
 
Originally Posted By: pbm


Before joining BITOG I thought you couldn't change your oil enough...that changing your oil every month (regardless of miles) would guarantee unlimited engine life. I now realize that the ability of oil to lubricate improves with mileage (Ford's study) up until the point that the oil starts to detiorate.


That study raised an interesting corollary/counterfactual I remember being discussed at the time - new oil done too often CAUSES more relative engine wear. LOL The fun never stops.
 
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I just came back from a trip to Fort Myers and I didn't change the oil in my Rogue before I left - but I did take a JetBlue airplane to get there
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IMO.
The oil in the OPs car is not half worn out. Doing anything to the oil, other than checking the level, is a waste of time and money. I would have thought that people that frequent this forum would come to the same conclusion.
 
The oil level is likely a little down after 4000 miles. Just top it off if you're worried. No way I'd get under the car to pull the plug and not drain all the oil.
 
Originally Posted By: Quattro Pete
But of course this will turn into another heated hair splitting debate, as is customarily the case on BITOG.
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Ya think?
 
If you feel you need to do something, change the filter and top it up. Filters are designed to go two OCI's anyway, so you could just leave it in there when you do the real oil change.

*posting to make the above prophecies of other suggestions come true
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Use good syn oil, dont worry about it change when convenient.

Personally though if it worried me enough to post about it.. I would have just changed it.
 
Originally Posted By: pbm
...
What are your thoughts on my theory?


Your theory seems sound.

I think it is a pretty much complete waste of time though. I suppose if you have a mityvac and can easily suck a quart out fine, but If I'm crawling under and pulling the drain plug, I'm not putting it back in until it is empty if for no other reason than it is going to make a mess.

There are in my opinion 3 answers to this question:

Change it pre trip.
Change it post trip.
Stop along the way and have it changed at the normal interval.

Keep in mind to that if you are just going to jump on a freeway and drone along basically constantly it may burn a little oil where it normally doesn't (or may not).

Originally Posted By: Quattro Pete
...But of course this will turn into another heated hair splitting debate, as is customarily the case on BITOG.
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Yeah, you're completely neglecting that equipment by going 5000 miles on a conventional oil and being extraordinarily wasteful by not running a sump full of bullseye for 25,000 miles....errr... wait...
 
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