The truth about oil change intervals and analysis

[kschachn]

But if the oil can't flow to the pump fast enough, it will suck wind, not oil as you pointed out. If it's -20F even 0W-16 is not going to flow like it would at room temperature. Nowhere close.

There is only one scenario where that will not happen and it is when the oil gels under shear at the pump intake. That was exactly the problem that was observed in the 1980s and caused a revision to J300. They discovered that the pour point test did not adequately represent oil that was rapidly cooled. Those goofy "watch the oil flow down the ramp" tests are just as useless in this regard. It's not how "fast" it flows to the pump, it's whether it will flow at all - and this is represented by the winter rating.

Like a lot of people you're fixated on this type of flow which isn't important. The winter rating represents the actual behavior of the oil near the pickup, so any oil with a 0W rating will have acceptable performance down to the temperature of the test. It will make it to the intake and it will be pumped and it will flow. The test for this behavior is much more complicated and representative than pour point or a YouTube freezer test.

 

[Cherrybomb]

I'll be changing the oil soon and give it a very distant sniff. We shall see.

On my car,I couldn't smell fuel,but I had 7,500 miles on the 10,000 mile recommended service.I was set to go on a long trip so I had the oil changed and analyzed.It came back excessive fuel dilution according to Polaris Labs.I do lots of short trips so it didnt really surprise me.When I got back on my normal routine,one change past the long trip,I changed at 5,000 with analsis,Again using Polaris, I now made 'Normal' ,so long story,short,In my case,and everyones is differnt,I now do 5,000 and feel the price of an analysis gave me the knowledge to shorten up.No right or wrongs,enjoying this thread as lots of good info presented here.

 

[kschachn]

You're missing the point. Yes, it will flow, but how quickly. The thicker it is at startup, the harder it is to pump. And the harder it flows, the slower it will reach the already moving parts. Which is where most say the bulk of engine wear happens.... At startup.

In a frigid Winter climate the whole concept is to balance the viscosity to allow for easy enough starting and sufficient cold flow, but still not be too thin at operating temperatures that are often over 200F.

With that said, back to my original question. On the low temperature end of this, which is thicker.... Or, which will flow easier and quicker. 0W-16 at -20F, or 0W-40 at 65F? Obviously at operating temperature the 0W-16 will flow easier, (perhaps too easy), because it is much thinner.

So yes it will take more horsepower to pump but only at the beginning. As soon as it begins to be pumped the oil will warm and the viscosity will decrease.

You're still stuck on the wrong kind of flow. Flowing faster in your example is only relevant for energy savings and it is highly transient.

 

[Joenpb]

We’ve seen that video. I don’t think many agree with your assertion about cheap oil. I prefer to use oil that meets specifications.

Former Nissan GT-R lead engineer on oil change frequency

I just thought people here might be interested.

bobistheoilguy.com

I'm well aware that many here prescribe to OEM OCI. I did for many years and often used top of the line synthetic oils. The take just makes sense to me. I like the idea of increasing the odds of not needing to purchase another vehicle, if maintained. Most vehicles are expensive whether new or used, and I would just as soon minimize additional loans. There are also many oil price points that will meet most OEM specifications. Thanks

 

[JohnnyJohnson]

I'm well aware that many here prescribe to OEM OCI. I did for many years and often used top of the line synthetic oils. The take just makes sense to me. I like the idea of increasing the odds of not needing to purchase another vehicle, if maintained. Most vehicles are expensive whether new or used, and I would just as soon minimize additional loans. There are also many oil price points that will meet most OEM specifications. Thanks

Minimized additional loans? I haven't had a loan on a vehicle since 1975.

 

[Astro14]

I'm well aware that many here prescribe to OEM OCI. I did for many years and often used top of the line synthetic oils. The take just makes sense to me. I like the idea of increasing the odds of not needing to purchase another vehicle, if maintained. Most vehicles are expensive whether new or used, and I would just as soon minimize additional loans. There are also many oil price points that will meet most OEM specifications. Thanks

Then, we disagree.

I won’t use anything that most folks would call “cheap” in any of my cars. Even changed often, many of those oils fail to meet important specifications. So, why take the chance?

My wife’s Volvo just crossed 299,000 miles. We paid cash for it in 2007, as a used car.

So, you and I agree on not having a car payment, we agree on the importance of getting value for your money.

But value doesn’t mean cheapest. If I compare the cost of running, say, HPL or AMSOIL for 10,000 miles vs. the cost of cheap oil at 3,000 miles, the HPL is equal or lower cost per mile. Each filter has a cost. My time has a cost. Total cost is about the same, but the boutique oil met a couple of key performance factors in the turbocharged engine that the cheap oil did not.

The proof of my assertion, the proof of my success, is the fact that the 2002 V70XC is still running great.

 

[billt460]

Here's the thing. The worst part of an oil change is doing it. It's a dirty job that for most people involves crawling around on your back.

So that being the case, (unless you're Jay Leno and are blessed with a lift), why not put the best oil in you can buy?

I can also put not changing the filter into much the same category. You're already under the vehicle and dirty, with a drain pan full of dirty oil. So why not change it at the same time? What are you saving, $7 bucks. A hamburger costs more these days.

 

[ZeeOSix]

That is what I'm more or less referring to. You can pump anything through anything with enough power. Hell, today they can pump concrete over 1,000 ft. high when they build high rises.

But if the oil can't flow to the pump fast enough, it will suck wind, not oil as you pointed out. If it's -20F even 0W-16 is not going to flow like it would at room temperature. Nowhere close.

0W-16 doesn't have to flow at -20F like it would at room temperature. It just has to flow good enough to meet the 0W rating to work correctly in a cold engine start-up. kschachn already explained it pretty well in post 201. In most of those PF "cold flow races" videos it's been pointed out many times that the flow by gravity does not always represent how they would rank in their relative CCS and MRV test results. Watch the videos, make note of how they rate by CCS and MRV in thier manufacture spec sheets, and see if that ranking correlates with the way they finish (rank) in the cold races. There isn't always the same correlation. An oil that doesn't finish first may actually have the best CCS and MRV viscosity for cold cranking and pumpability in a real engine.

The CCS and MRV cold viscosity tests were invented to determine how the cold oil will behave when an engine cranks over (CCS viscosity) and how the oil will pump (MRV pumpability viscosity) once the engine fires up. If an engine fires up, the oil better be able to flow to the pickup and be pumped by the oil pump. That's what those tests are determining. So based on those test and the resulting viscosity measurement, the "W" (winter) rating in SAE J300 is determined. If an engine manufacture say to use xW rated oil down to xF cold start temperature, then they have determined that the engine will crank over and start, and the oil will flow to the pickup and be pumped and distributed throughout the oiling system. If the engine manufacture recommends a 5W for your use starting conditions, then it will do it without issues, but if you want to be "more sure" it will then use a 0W winter rated viscosity. Using a W rating higher than the lowest it's recommend for it asking for problems of course - ie, don't use 20W-50 and expect it to work well at -25F (-32C).

 

[ZeeOSix]

I remember there was a Oldsmobile V-8 that had issues with oil not being able to return to the pan fast enough at high RPM's. This would in turn cause the oil pump to suck air, because all the oil ended up at the top end.

My neighbor had a jet boat with that Old's V-8 engine, and he said they had some kind of fix, (kit), that would remedy the problem. It was really bad with boats because they ran at very high RPMS for a long time.

And boat engines run a lot cooler, because most of them have water cooled manifolds, along with a lake full of cool water flowing through them.

Put that same engine in northern Minnesota in January at -20F, and it's not going to matter much what you put in the crankcase, it's not going to flow back to the bottom as fast as it can be pumped to the top end. At least not until some heat builds up in the motor.

Hard to say what was going on in those engines. Obviously, if someone put a higher flow aftermarket oil pump on an engine and revved it to near redline for a long time before the oil was fully warmed up the sump will run at a lower level than if the oil was thinner/hotter. The pump flow rate, the drain back to the sump paths, the capacity of the sump and the recommend oil viscosity all play a part on how the system works in all conditions. High performance engines typically have a larger oil sump (8-10 quarts) to help keep oil over the pump pickup during high RPM use.

In other threads, it's been mentioned once in awhile on how much flow some of the Subaru engines flow near redline ... it's something around 15 GPM if I recall correctly. If the sump is 5 quarts, then the sump is turned over every 5 seconds (pump flows 60 quarts in a minute, so 5 qts in 5 seconds). The oil better be able to flow back to the sump very well in that case. Fire that engine up in really cold weather, start driving it near redline before the oil warms up much and the sump may very well get low and cause the pump to suck air. The best thing anyone can do when starting any engine in cold weather is let the oil warm-up pretty good before getting nuts with the revs.

 

[Scout1]

I just got around to watching this video and thought it was really good! But it's been a lot tougher to read through this 11 page post to make sure I didn't say anything stupid... I know everyone is fixated on the OCI but what I found kinda interesting was Lake's discussion of the ZDDP history and role in engine break-in. It's all stuff I've read before on BITOG but I thought this video was a good succinct description. That and his gapless (2)ring discussion at the end... first I've seen of that.

 

[ChrisD46]

Oddly our 1.5T fuel diluter CRV DOES NOT fuel dilute

Premium fuel and good 0W-30

Too easy

Why high octane gas is part of the equation ? If you use a Top Tier gas and your vehicle is rated for 87 octane - then why use higher ?

 

[billt460]

Why high octane gas is part of the equation ? If you use a Top Tier gas and your vehicle is rated for 87 octane - then why use higher ?

A lot of the time it's because while the engine will run somewhat satisfactory on 87, it won't produce its full performance. This is especially true with many turbocharged engines.

 

[Pablo]

Why high octane gas is part of the equation ? If you use a Top Tier gas and your vehicle is rated for 87 octane - then why use higher ?

Please read the entire thread.

Discussed previously.

More fuel enrichment with lower octane fuels, under boost. Sure it can and does exactly as you say, run on lower octane. But not necessarily ideally.

Search results for query: enrichment

 

[Triple_Se7en]

Why high octane gas is part of the equation ? If you use a Top Tier gas and your vehicle is rated for 87 octane - then why use higher ?

....cuz' in my findings, the vehicle(s) run better on Premium.
I'm now going on six straight new vehicles purchased over the past 30 years, where they all ran OK on Regular, but all ran better on Premium.

If you got TGDI / GDI, they will produce noticeably less carbon using Premium also. A perfect example is the need to drive around a corner without stopping, then needing to produce much more RPMs to resume the city block speed limit.

With Premium (my findings), I can accelerate slowly and smoothly, with no need to go from 1.5RPMs to 4.5RPMs to avoid hesitation when increasing speed. I gradually increase speed after that turn around the corner and boy does it run smooth - no passing gear on the tranny needed either.

None of those past six vehicles would give me such smoothness around corners on Regular 87 octane. That's why I always use 93 octane and filled-up today at BJ's, which is BP fuel trucks in our County. Paid $4.18 per gal. The pump's Regular was $3.38 today and this gasoline is noticeably better than Costco or Sam's gas.

 

[Fa24wrx]

Sure. I’m not saying PCEO applications are great for used oil analysis. If I had to pay for it, the fact would be I’d do it rarely. Assuming say 5000 mile oil change intervals. I would probably do it every 4th or 5th oil change. As, that would give you a fairly good idea of your operation changes.

And I’m saying that as someone, technically formally trained in this field.

I’m more along the lines of being confused that in around 100 year of oil technology, we’ve only been able to get it to 3000 miles? Like… really? That’s what gets me with the whole “change it early and change it often” thing. I have turbine oils, in operation, that they stopped doing the TOST test with them at <25,000 hours. I’ve personally had one of my own semi trucks go <88,000 miles without an oil change. But ****, if you wait longer than 5000 miles in a normal car, darn thing might as well be towed to the scrap yard.


I’m not complaining. Don’t get me wrong. I literally make my living selling people oil. If you want to change oil more often, great. It normally goes to either myself, or keeping one of my friends in this industry employed. Buuuuutttt you know, you don’t reaaalllly need to do that.

Remember manufacturers OCIs are based on the minimums. So if you’re exceeding the minimums, you’re going to be good for, longer. How much longer? That’s where UOAs come in.

So, tell me what you think about this:
Subaru says 6k mile OCI under normal conditions or 3k under "severe". That includes short trips, driving it "hard", hot climates. I do 3.5k mile intervals because I like driving my wrx pretty hard and I live in Georgia.

Getting 5k oci is getting close to the "normal" driving conditions and too long imo. Thoughts? I can/probably will do an analysis at some point but I would rather do an oil change for the same price.

 

[Revving2Redline]

Fuel Dilution.

The new bogey man.

There are ways to control and ameliorate fuel dilution.

Like driving it long enough to get it up to temperature on a regular basis;idling is awful and same with stop and go. Wondering if slightly high octane and slightly lower ethanol content could help. Everyone thinks ethanol is a great cleaner, but it's a solvent and probably is harder on engine parts where fuel and oil meet. Cars that allow e85 list to have more frequent oil changes and my theory is exactly because of higher dilution. If those were my problems in a vehicle I would start with a better oil and maybe a tad thicker too. I've seen more vehicles with issues that hardly go anywhere than everywhere.

 

[Revving2Redline]

....cuz' in my findings, the vehicle(s) run better on Premium.
I'm now going on six straight new vehicles purchased over the past 30 years, where they all ran OK on Regular, but all ran better on Premium.

If you got TGDI / GDI, they will produce noticeably less carbon using Premium also. A perfect example is the need to drive around a corner without stopping, then needing to produce much more RPMs to resume the city block speed limit.

With Premium (my findings), I can accelerate slowly and smoothly, with no need to go from 1.5RPMs to 4.5RPMs to avoid hesitation when increasing speed. I gradually increase speed after that turn around the corner and boy does it run smooth - no passing gear on the tranny needed either.

None of those past six vehicles would give me such smoothness around corners on Regular 87 octane. That's why I always use 93 octane and filled-up today at BJ's, which is BP fuel trucks in our County. Paid $4.18 per gal. The pump's Regular was $3.38 today and this gasoline is noticeably better than Costco or Sam's gas.

I wouldn't put Costco in with Sam's . Seems alot of these newer cars can run 87, but I have a feeling they are fed more fuel than necessary but do so to prevent detonation where 89 or 91 would not need to run as rich. Could explain all the excessive fuel in oil issues

 

[JohnnyJohnson]

My two year old Mazda is running 92 Octane nonethanol it doing just fine. I'll be doing another UOA in a few weeks here the first on showed a very minute amount of fuel dilution.