why OCI's are variable ?

[gasman556]

I'm hoping to get clarity on this. Assuming I am running a high end oil (HPL/Amsoil SS) and I don't have a turbo, please help me understand what exactly makes the oil lose its ability to protect the engine.

Is it:
1- fuel dilution
2- pH dropping
3- additives coming out of solution/consumed
4- VII loss
5- ?

Assume no oil loss, other consumption of the oil volume between changes. I watch several YT mechanics who consistently harp on 5k OCI regardless of driving styles, etc and I already pay for the high end oil/UOA/good filters. I am seeking clarity on what exactly causes the 5k OCI recommendation aside from historical precedent. TIA.

 

[gfh77665]

Short trips will contaminate the oil. It depends how you drive.

 

[gasman556]

Short trips will contaminate the oil.

so fuel dilution? soot?

 

[gfh77665]

Yes.

 

[gasman556]

Short trips will contaminate the oil. It depends how you drive.

thanks. How short is a "short trip"? If I'm driving at least 15 miles a trip, is that short still?

 

[Patman]

thanks. How short is a "short trip"? If I'm driving at least 15 miles a trip, is that short still?

15 miles isn’t a short trip as that’s sufficient time to get the oil fully up to temperature. It’s the ones that do 10 miles or less per trip that would be considered short tripping

 

[gfh77665]

Yes, your engine needs to drive some after fully warming up to rid itself of condensation and dilution. 15 minutes might get it just warmed up, but then there is not much driving after that. Most people would say 30 minutes, but vehicles vary. A four cylinder works harder, faster than a large V8, for example.

 

[Kira]

Don't overlook ingested air. Even though there's an air filter, no air filter is 100%.
"The best oil filter is a good air filter", goes one time-honored expression.

I routinely make 4 hour highway runs. I firmly believe these "cleansing runs" have contributed mightily to my engines' health.

My dear mom only got her license because my dad died. She was THE quintessential short-tripper.
Her cars would develop shaky idle and sometimes sputter. She'd call and tell me to take her car on my long run.
She knew...her dad sold farm equipment.
The cars ALWAYS came back noticeably smoother running. <<Real, not a psychosomatic effect-though I never had a way to measure it.

 

[tcp71]

Don't overlook ingested air. Even though there's an air filter, no air filter is 100%.
"The best oil filter is a good air filter", goes one time-honored expression.

I routinely make 4 hour highway runs. I firmly believe these "cleansing runs" have contributed mightily to my engines' health.

My dear mom only got her license because my dad died. She was THE quintessential short-tripper.
Her cars would develop shaky idle and sometimes sputter. She'd call and tell me to take her car on my long run.
She knew...her dad sold farm equipment.
The cars ALWAYS came back noticeably smoother running. <<Real, not a psychosomatic effect-though I never had a way to measure it.

The truck sees a lot of short-er city trips during the winter. It gets a bit rougher running over that time. The first trip towing the trailer in the summer gets it back on vibration fee idle.

 

[WobblyElvis]

On a highway trip the vehicle covers much more ground in a shorter time. The engine turns over less per mile. RPM more constant and throttle variation is less. All this is easier on the oil, per mile. A good Oil Life Monitor takes this into account. Changing oil by just a mileage figure is an unmindful thing to do.

 

[dnewton3]

I watch several YT mechanics who consistently harp on 5k OCI regardless of driving styles, etc and I already pay for the high end oil/UOA/good filters. I am seeking clarity on what exactly causes the 5k OCI recommendation aside from historical precedent. TIA.

Generally, these YT mechanics are just that; they are not tribologists. Many of them make assumptions based on poor information, and lack of understanding. Further, it's easy for them to offer a one-size-fits-all answer; makes for less discussion and nuance of explanation.

The reality is that any lubricant can be over or under utilized. So, for any given application and use, some lubes will be more capable than others, depending on a host of factors well discussed on this site dozens thousands of times ...

 

[gasman556]

On a highway trip the vehicle covers much more ground in a shorter time. The engine turns over less per mile. RPM more constant and throttle variation is less. All this is easier on the oil, per mile. A good Oil Life Monitor takes this into account. Changing oil by just a mileage figure is an unmindful thing to do.

Disagree about OLM's (Honda/Toyota anyways) as all they are is another trip computer you reset IME. Zero input via driving trip length/idle time/etc vs just a simple 10k trip countdown. GM's supposedly is dialed in - the Honda/Toyota's not so much.

Don't overlook ingested air. Even though there's an air filter, no air filter is 100%.
"The best oil filter is a good air filter", goes one time-honored expression.

I routinely make 4 hour highway runs. I firmly believe these "cleansing runs" have contributed mightily to my engines' health.

My dear mom only got her license because my dad died. She was THE quintessential short-tripper.
Her cars would develop shaky idle and sometimes sputter. She'd call and tell me to take her car on my long run.
She knew...her dad sold farm equipment.
The cars ALWAYS came back noticeably smoother running. <<Real, not a psychosomatic effect-though I never had a way to measure it.

Italian tune up maybe?

Good filtration is a solid point, sure! Assume this is taken into consideration.

 

[gasman556]

Generally, these YT mechanics are just that; they are not tribologists. Many of them make assumptions based on poor information, and lack of understanding. Further, it's easy for them to offer a one-size-fits-all answer; makes for less discussion and nuance of explanation.

The reality is that any lubricant can be over or under utilized. So, for any given application and use, some lubes will be more capable than others, depending on a host of factors well discussed on this site dozens thousands of times ...

I know the "motor oil geek" is often cited on the boards in a negative light on some of his takes but he does a good bit of tribology via his channel iirc. I appreciate what he's taught me and the lengths he goes to as well.

I tried to search for some of these reasons I'm seeking to try and be efficient in lube, but found threads that weren't what I was looking for or maybe the info was buried in 35 pages of content.

 

[Patman]

Disagree about OLM's (Honda/Toyota anyways) as all they are is another trip computer you reset IME. Zero input via driving trip length/idle time/etc vs just a simple 10k trip countdown. GM's supposedly is dialed in - the Honda/Toyota's not so much

I can speak for the Honda oil life monitor that it’s definitely not just a countdown. It will call for shorter intervals with people who drive the cars harder and do more short trips.

 

[BMWTurboDzl]

I'm hoping to get clarity on this. Assuming I am running a high end oil (HPL/Amsoil SS) and I don't have a turbo, please help me understand what exactly makes the oil lose its ability to protect the engine.

Is it:
1- fuel dilution
2- pH dropping
3- additives coming out of solution/consumed
4- VII loss
5- ?

Assume no oil loss, other consumption of the oil volume between changes. I watch several YT mechanics who consistently harp on 5k OCI regardless of driving styles, etc and I already pay for the high end oil/UOA/good filters. I am seeking clarity on what exactly causes the 5k OCI recommendation aside from historical precedent. TIA.

Historical Precedent. Especially when conventional oils had been allowed.

 

[gasman556]

I can speak for the Honda oil life monitor that it’s definitely not just a countdown. It will call for shorter intervals with people who drive the cars harder and do more short trips.

meh. Empirically I can say it's just a glorified trip odo regardless of trip length. I would also say given how heavy their odyssey's are that any drive is "hard."

 

[Patman]

meh. Empirically I can say it's just a glorified trip odo regardless of trip length. I would also say given how heavy their odyssey's are that any drive is "hard."

I have owned two Civics now with the oil life monitor and I can say with 100% confidence that they don’t use a “glorified trip odo”.

 

[ripcord]

The problem with short trips is not just that moisture is not driven off. Before the engine warms up, the pistons haven't expanded from heat and the rings aren't sealing as well, so more combustion products are making it into the oil. There are also elements in the oil additive pack that need heat to work fully as designed.

 

[dnewton3]

I know the "motor oil geek" is often cited on the boards in a negative light on some of his takes but he does a good bit of tribology via his channel iirc. I appreciate what he's taught me and the lengths he goes to as well.

Lake Speed Jr. (aka LSJr or the motor oil geek) is not the typical "YT mechanic" to which you referred in your original post.
His videos are met with varying degrees of acceptance here on BITOG.

 

[gasman556]

I have owned two Civics now with the oil life monitor and I can say with 100% confidence that they don’t use a “glorified trip odo”.

I'm happy for you. Again, this is not my experience.

Lake Speed Jr. (aka LSJr or the motor oil geek) is not the typical "YT mechanic" to which you referred in your original post.
His videos are met with varying degrees of acceptance here on BITOG.

right. I think he too is not a fan of extended OCI's iirc though he does have his own oil analysis company. With that said, I may be conflating his video's with some of the others I've seen.