What Might Cause Consumption in Extended OCI

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I've got about 130,000 miles on my 2000 Honda Insight. For the last 110,000 miles, I've been using Pennzoil Platinum 0w20. The car has never consumed any oil during the 7,500 mile oil change intervals -- at least not anything that I can detect. I've got enough PP 0w20 remaining for one more oil change and I'm thinking of trying a different 0w20 after that.

I'm considering switching to Mobil1 EP 0w20 and stretching the OCI to 15,000 miles. My question is this:

Having never consumed any detectable amounts of oil during the 7,500 mile OCI, if I went to 15,000 mile OCIs, what might cause consumption IF my car did start consuming oil? For the sake of this discussion, I'd like to rule out the possibility of any mechanical problems emerging in the car. Would consumption during an extended OCI point to a depleted TBN, only? Would there be other reasons for consumption to start during an extended OCI?

My reason for asking this question is that while I'm considering switching to M1 EP 0w20; and I'd like to go 15,000 miles per OCI, I'm not interested in doing so if it means that I'll have to start adding top-up oil during the OCI.

Thanks for your thoughts,
Bryan
 
Originally Posted By: friendly_jacek
If there is no oil consumption, why one would start with extended OCI?


Sorry, that is specifically what I'm asking -- is there something, inherent in extended OCIs, that would cause consumption. And if so, what it is? Disregard my car in the original question, as I'm asking the question more generically.

Thanks,
Bryan
 
Originally Posted By: tomcat27
General thinning of the oil and dilution can increase consumption


That is my thought too. The longer the OCI the more the possibility of shearing and fuel dilution.
 
Why change what has worked so well for so long? You're not putting a ton of miles on the car, a 15k mile OCI would probably take over a year looking at your average.

I can't tell if my car consumes oil, it leaks too much Lol.
 
Consumption is usually caused by an oil that's too thin for the application. Either that or the engine is worn out from using an oil that's too thin for the application.
 
Why, I cannot satisfactorily explain. However, it's been my experience that if an engine does consume oil, it will consume more towards the end of an OCI. So, if that experience is typical, then it would stand to reason than an extended OCI might expose oil consumption, whereas in some OEM mandated severe service interval, no consumption may be noted at all.

There were many examples with the taxis. After an oil change, even the oil burners wouldn't need a top up for a week or two. Then, as the OCI progressed, they'd revert to their top ups every couple days.
 
Can't say i have ever noticed any difference with longer oci.

And if fuel dilution is an issue then the car is using oil anyway. It is just being masked by the increase in oil level caused by fuel dilution, surely.

Wether this is more of an issue with dino/conventional oil i don't know.

I run full synth pretty much exclusively these days.

And have used semi synth previously and a couple of times i have used synth blend
 
Originally Posted By: Garak
Why, I cannot satisfactorily explain. However, it's been my experience that if an engine does consume oil, it will consume more towards the end of an OCI. So, if that experience is typical, then it would stand to reason than an extended OCI might expose oil consumption, whereas in some OEM mandated severe service interval, no consumption may be noted at all.

+1. It depends on driving style too and the current UOA trend over previous 3 UOA's at least. Then one can comment if it is expected to consume oil in an extended OCI.

Bryan if you are staying with same oil grade 0w-20 from PP to Mobil1 then extended OCI should not lead to any questionable oil consumption. All this assuming engine is in excellent health.
 
Originally Posted By: Nick1994
Why change what has worked so well for so long? You're not putting a ton of miles on the car, a 15k mile OCI would probably take over a year looking at your average.


I agree. The "play it safe" side of me wonders why I would change what has worked so well for so long. Having said that, in the early years of my Insight, very few miles were put on it. Currently, however, I'm putting about 20,000 miles a year on it. So the 15K interval would take me about 9 months. (The "play it safe" side of me, might still win out in the end.)

-Bryan
 
Originally Posted By: Garak
Why, I cannot satisfactorily explain. However, it's been my experience that if an engine does consume oil, it will consume more towards the end of an OCI. So, if that experience is typical, then it would stand to reason than an extended OCI might expose oil consumption, whereas in some OEM mandated severe service interval, no consumption may be noted at all.


The only time I ever did an extended OCI, this was my experience, also. On my wife's '03 Ford Focus, there is no noticeable consumption on the 5,000 mile OCI with 5w20 or 0w20. However, about 5 years ago, I ran Amsoil's 0w20 in it (it was not the XL version). I was attempting to do 1 year on the OCI which would have been about 15,000 miles. However, around 12,000 miles, it started consuming oil. It made me uncomfortable and so I returned to 5,000 intervals.

-Bryan
 
Originally Posted By: fpracha
Bryan if you are staying with same oil grade 0w-20 from PP to Mobil1 then extended OCI should not lead to any questionable oil consumption. All this assuming engine is in excellent health.


Sounds hopeful. Maybe I should give it a shot.

Thanks,
Bryan
 
Originally Posted By: Bryan K. Walton
Originally Posted By: Garak
Why, I cannot satisfactorily explain. However, it's been my experience that if an engine does consume oil, it will consume more towards the end of an OCI. So, if that experience is typical, then it would stand to reason than an extended OCI might expose oil consumption, whereas in some OEM mandated severe service interval, no consumption may be noted at all.


The only time I ever did an extended OCI, this was my experience, also. On my wife's '03 Ford Focus, there is no noticeable consumption on the 5,000 mile OCI with 5w20 or 0w20. However, about 5 years ago, I ran Amsoil's 0w20 in it (it was not the XL version). I was attempting to do 1 year on the OCI which would have been about 15,000 miles. However, around 12,000 miles, it started consuming oil. It made me uncomfortable and so I returned to 5,000 intervals.

-Bryan



I have personally witnessed behaviour like this before. Little to no consumption for the first x miles, and then near the end, some consumption results. I'd have to say that a combination of shear and the repeated effects of fuel dilution (even if no fuel is detected in the oil sample at the end of the OCI) can cause this. In my scenario, it was with my old 3.5L V6 Nissan VQ engine in my Altima. This engine always consumed a little bit of oil (nothing to be concerned with), but after the first 10,000 km (6200 miles), consumption started creeping up - again, nothing major, but more than the first part of the OCI. However, it was more noticeable in the winter were fuel dilution effects were worse (the car was mostly highway driven, so you would never actually find fuel in the oil when drawing a sample, but you could see the effects of it via a depressed flashpoint, tbn, certain wear metals, and viscosity measurements). The car was also slightly modified, and tended to run rich on throttle tip in, which was notably worse in the winter and very driving dependent (i.e. steady highway cruise or lots of throttle inputs / passing manoeuvres, etc).

However, this is very vehicle dependent. My current vehicle specifies 20,000 km oci's (13,000 miles) and burns no oil whatsoever during those OCI's, no matter how it's driven or in any weather. So I'd suggest you try it. Even if it requires 1/2 to 1 qt of top up over the entire 15k OCI, I personally wouldn't see that as an issue for the increased convenience and cost savings of the extended OCI.
 
I'd be interested in seeing if I can replicate the taxi experience with modern oils. The only old engine I have is the F-150, so I guess it'll take time.
wink.gif
 
IMO, go with your original idea of switching to Mobil 1 0w20 AFT, but extend your OCI to about 9 to 9.5K. Mobil guarantees to oil to 10K

The combination of M1 0w20, and a Fram ULTRA filter, has worked great for me over the last few oil changes. My last OCI was 9,200 over 13 months, and there was no oil consumption, nor has there ever been.
 
I've experienced this with my G35. No oil is used for about 3k miles, then it will use a quart by 4,500 and another quart before 6k - at which point I usually change it. My last OCI took 2 quarts between 3k and 5k.

This has been consistent over many M1 0w40 and PU 'euro', I have even tried underfilling it slightly so that I know the measurement is the same.

I have tried to match patterns with driving style, weather, trip type, etc. Never had any luck. My driving style is pretty consistent, I spend 90% of my time between 2,800 and 4,000 rpm. The rest is either idling or driving aggressively.
 
When my wife and I first moved up to N NJ my driving in my f150 went from 90% highway to perhaps 30%. I was using Amsoil SS 5-20 with little to no usage over a year/15K avg to perhaps 1.5 QT in the first 3 months after we moved (perhaps drove 2.5K miles during that time). I switched to XL 5-20 and a 6 month interval and usage went back to nil. I think the stop and go/short trips never let the engine run long enough to burn off the moisture and possible fuel in the oil. I still do a long OCI in my wife's Focus ('02, 119K miles) of about 1yr 22K avg, with ss 5-20, but her OCI is 90% highway.

I do know that my wife's Focus did not like M1 extended the one time I used it. She had no usage for perhaps 12K miles/7 months, and then it slurped down 1.5 quarts. I switched it over to SS at that time and no usage since.
 
Originally Posted By: KitaCam
Some engines "use" more oil in stop 'n go around-town driving, others more at extended highway speeds (>80mph)...


+1

I'm so glad I read that because it was driving me insane.
Our 06 Camry 2.4L burns 1 quart in 2000 miles city, where it burns 1 quart in 6000 miles highway.
01 Celica GT burns 0.75 quart in 4000 miles city, where it burns 0.75 quart in 2000 miles highway.
 
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