Truth about oci.

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I just wanted to know the truth about whether changing oil early is better for the engine. I do 3,750 oci in the Hyundai. That's what the car calls for under severe service. But today I accidently changed out the qsud5w30 at 3000 miles. I noticed how clean the oil looked in the filter and when I checked my notes I realized I did it early. Guess what im asking hear is doesn't brand new oil protect better then oil say at the end of the interval.
 
I would say its a minor difference either way. Likely there is more risk with long OCI's so they have to be managed carefully. Overall I would never worry about short OCI's.
 
The one actual test using multiple vehicles (taxis) with actual before and after internal measurements Ive seen said its detrimental. Synthetics had no advantage with 6000 mile drains and the cars with the lowest wear used 12000 mile drains on synthetics.
 
I wasn't worried about changing it out early. I know it was wasteful but like I said it was a mistake. I just don't understand why so many people on hear think that extended oci is good for an engine.
 
Originally Posted By: waltywalt
I wasn't worried about changing it out early. I know it was wasteful but like I said it was a mistake. I just don't understand why so many people on hear think that extended oci is good for an engine.


Try searching for this.
http://web.ornl.gov/~webworks/cppr/y2005/pres/117987.pdf
 
Originally Posted By: waltywalt
I wasn't worried about changing it out early. I know it was wasteful but like I said it was a mistake. I just don't understand why so many people on hear think that extended oci is good for an engine.



I don't think anyone is saying it's good for an engine. It's more about not being harmful for the engine (assuming your OCI is within the abilities of the oil), and therefore saving time and money.

You said you know it was wasteful changing your oil out at 3k miles. You said that b/c you're sure your oil can go 3750 miles based on the manufacturer's recommendation. Assuming you're out of warranty and don't have to worry about following the manufacturer's recommendation, would you still change your oil out every 3k-4k miles if you knew your oil could easily go 7500 miles? A lot of people on here are in that scenario and decide to do 6k-7k mile OCIs or more, because they're sure the oil can handle it.

So it's not about it being *good* for the engine, it's about it not being harmful for the engine, and it save the time and money that goes into performing an oil change.
 
The way I've seen it described here is that the oil lubricaates better and better and the filter filters better and better---until they don't.

So, although it may not in any practical way hurt the car to do a particularly short drain interval its in no way an improvement. So, if the manual calls for a change at 7K which is let us assume, conservative, there is no benefit to changing at 5K let alone 3K.

In real life, you are probably neglecting something that would be helpful to do all these ultra-short intervals.
 
Changing oil is only wasteful to those that don't change it as early as the other guy does. Used oil is recycled (unless Bubba dumps it in the creek that runs behind his house) so it gets re-refined and used again. So that take care of the wasteful argument. And it is only wasteful if the owner is pitching a fit about buying more and putting it in. In that case, they should stretch the drain if changing early causes they're hair to fall out, right? Of all the things people "waste" their money on, changing the oil a little early doesn't even make a blip on the radar.
 
3750 miles would be considered an extended OCI for me.

It would have to be staying pretty clean for me to let it go that far.
 
Originally Posted By: TiredTrucker
Changing oil is only wasteful to those that don't change it as early as the other guy does. Used oil is recycled (unless Bubba dumps it in the creek that runs behind his house) so it gets re-refined and used again. So that take care of the wasteful argument. And it is only wasteful if the owner is pitching a fit about buying more and putting it in. In that case, they should stretch the drain if changing early causes they're hair to fall out, right? Of all the things people "waste" their money on, changing the oil a little early doesn't even make a blip on the radar.


I don't disagree. My point is not that its "wasteful" so much as it competes with other needs that are more usefully attended to. For example, the differential oil in my car only needs to be changed every 150K. Does it make sense to change the oil at say, 4K instead of the required 8K, but let the diff go the full 150K?

I know a lot of people change all fluids early, and a lot of people change by the book, period. What makes no sense is to change the oil somewhat obsessively and let the other stuff go, especially the cosmetic appearance of the car. A lot of people do that, too. I'm trying to make a better effort this time to keep on top of the whole car
 
That's a good point, Jim. I tend to do that...all mechanical maintenance and not much on the appearance. Part of it is the fact that I keep vehicles so long/old that they look their age regardless. But keeping on top of things like broken door handles, radio knobs, paint care, etc, would sure increase the joy of ownership.
 
Originally Posted By: Merkava_4
3750 miles would be considered an extended OCI for me.

It would have to be staying pretty clean for me to let it go that far.

You should get the OCD checked.
lol.gif
 
Originally Posted By: TiredTrucker
Used oil is recycled (unless Bubba dumps it in the creek that runs behind his house) so it gets re-refined and used again. So that take care of the wasteful argument.


Just a quick comment: while recycling is definitely much better than dumping, reducing is much more environmentally friendly. It's not like recycling doesn't require energy whether it is transporting the oils, refining it or re-packaging it.
 
If your sticking to the 3,750 OCI I would go with dino oil. No sense in wasting a good synthetic in that short period of a run. I'm running QSAD 5W-30 in my 2014 Elantra and doing 4K OCI.
 
With my daily drive being easy on oil and no real winter to worry about, 7,500 mile (mfr recommendation) intervals is what I will do with the Sonata 2.4L. I've seen two or three uoa's on the Hyundai forums where QSGB did absolutely fine at ~this distance, comparable even to many synthetic uoa's.
 
Like most things here, it depends. For example, I own a VW TDI BRM, and the rec OCI is 10k. With that, I have read data suggesting that reducing this OCI will actually increase wear. I believe the conjecture is soot in suspension provides part of the protection.

On the flip side, I also have a 996TT, and the consensus there is changing in 3-5k due to turbos, heat, IMS, etc. This is well below the factory suggestions.

Finally, my wife has a Tiguan, and the rec OCI is 10k. Given some of the problems Ive heard about sludge in Audi turbos, I change at 5k.

In a perfect world, an alarm would go off telling us that optimal protection is passed, and the onboard computer would give us an infallible message regarding what oil to put in for optimal protection. Unfortunately, no such device exists, so we are relegated to best guesses and lose empirical interpretations. That's one of the reasons for these forums I suppose...
 
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