Why 20wt Stubborness??

[Smokescreen]

I have been frequenting this forum for quite a while now and it seems there is a cyclical argument over the effectiveness 20wt oil on modern day vehicles that ask/require them. I myself have been torn both ways by convincing arguments from the 30wt diehard holdouts, and those that have accepted the advances and have run the 20wt.

I guess the most convincing argument to hold me back (as well as others) from accepting the 20wt as the new standard are:
1) engines that once used 30wt now using 20wt appearing to be driven by CAFE, and
2) the perception that most buyers have that manufacturers only care that the engine lasts long enough to meet warranty and somewhat keep their reputation. Sure the wear numbers look good when the engine only has 20K miles on it, what engine wouldn't?

I can dig up many 20wt UOA that show great wear numbers but I can't refine the search enough to capture engines that have 100-150,000+ miles using 20wt oils. I think that if we could be shown that engines can last just as long as the 30wt engines have, it would be helpful. Perhaps this has already been done, but like I said, I can't seem to find it.

 

[JHZR2]

I wouldnt necessarily believe that just because an engine has 100-150k, it HAS to have higher wear numbers/rates. I think that is false.

Meanwhile, look at any UOA from any 5w30 conventional. Most shear out of grade pretty quick, so they are effectively 20wt oils.

What we do know is that actual 20wt oils are formulated on the thicker side, so they are no different than a sheared 30wt. We also know that the leading specs for 20wt oils, i.e. honda primarily, ford Id assume too, are pretty stringent. So we know what we are dealing with a lot better.

IMO, it is a dual issue problem. Owners manuals are dumbed down - no longer does the viscosity vs. temperature chart exist in most manuals... it is just one product for all of the US, for any use profile. However, that one product is of higher quality, and has a much better-known performance. These oils are operating with better basestocks, better additives, and in equipment with better metallurgy and process control than even what existed a few years back.

You can look at the backwards compatible engine series and make two determinations - a) that the better oil ENABLES them to be run on a lighter oil, or b) that design specifications are such that a lighter oil with known, established chemistries is suitable for "adequate" protection.

Now, quantify adequate... Is adequate enough for consistent, low wear UOAs? Does it mean that the engine will get through warranty? To a design mileage of 100k? 150k? Does it just mean that the engine is less tolerant to mashing the go pedal, but routine driving makes no difference? Therein lies the question.

I think that what we are starting to see is that proper, gentle driving with any oil that is in good service will yield a long engine life. Some will provide more power to the pavement, some will give better fuel economy, some may produce less wear. But for all practical purposes, even the 20wt oils are providing sufficient protection to ensure good service life from your engine.

JMH

 

[Doug Hillary]

Hi,
Smokescreen - SAE20 lubricants have been a mainstay with engine maunfacturers for tens of decades! They were very popular with American engine makers prior to WW2. In the 1950s for example most British and German cars were fed 20W-20 lubricants with great success. In the mid 1950s 10W-30 became popular with NA engine makers and this spread to Europe in the last 1950s.

The first 20W-50 lubricant was formulated in 1957-8 by Duckhams for the 1959 release of the Mini (the mini skirt came about 1961-2)

You can use any modern SAE20 lubricant with confidence where it is specified - the synthetics are especially good at their task!

 

[d00df00d]

Originally Posted By: Smokescreen
I guess the most convincing argument to hold me back (as well as others) from accepting the 20wt as the new standard are:
1) engines that once used 30wt now using 20wt appearing to be driven by CAFE, and
2) the perception that most buyers have that manufacturers only care that the engine lasts long enough to meet warranty and somewhat keep their reputation. Sure the wear numbers look good when the engine only has 20K miles on it, what engine wouldn't?

Keep in mind, those are guesses. They have yet to be fully substantiated.

 

[Gary in Sandy Eggo]

Been thinking about this myself. Here's what I conclude in my own tiny mind.

1. Heavy duty use has always benefited from an oil thick enough to keep moving parts separated. At full operating temperature this means viscosities associated with SAE-40-50 oils (say 16-20 Cst).

2. Most automobiles seldom see heavy duty use. Consequently, under most driving conditions, SAE-20 viscosity oil is adequate to keep moving parts from touching. However, anti-wear additives help during the few occasions that said light-duty momentarily slips into the heavy duty range.

3. Many automobiles spend most of their hours at less than full operating temperatures which, in turn, renders the oil thicker than specified at full operating temperature. This provides sufficient viscosity to keep moving pieces apart.

4. Since so many cars spend so much of their life at less than full operating temperature, they can benefit gas mileage-wise from a thinner oil which is more than thick enough to provide maximum protection at those reduced temperatures.

5. Having your temperature gauge go quickly to operating temperature does not reflect the oil temperature which comes up to operating temperature much more slowly.

That's sorta my opinion as to why 20 wt oils can be sufficient while offering a slight improvement in fuel consumption.

 

[rationull]

Originally Posted By: JHZR2
Does it just mean that the engine is less tolerant to mashing the go pedal, but routine driving makes no difference? Therein lies the question.


And that one is an interesting question. Even Honda still specs 5w30 for the Civic SI and the S2000. However, Ford specs 5w-20 for the Mustang GT's 300 hp 4.6 V8. While that V8 has relatively low specific output by many modern standards (65 hp/L vs 77 hp/L for the current economy trim Civic for instance, and less specific torque than the Civic's 1.8 as well), I think it would be a stretch to say that it's expected to put up with merely "routine" driving.

 

[Smokescreen]

I appreciate these responses guys. I share with most if not all the same opinions. This can (and has) banter back and forth between "adequate and acceptable" to "not in this application or this one" until the thread loses momentum and dies, only to be revived again by another.

I am not saying that an older engine always shows higher wear numbers. What I am saying is that a maintained engine fed 30wt (synth or conven. no matter) has established a certain standard acceptable wear numbers by the time it has reached maturity of 100-150-200,000 miles.

My question is, do the 20wts show this same standard by the time it reaches the same age? If so, why aren't these being posted so we can bury this and say yes 20wt are acceptable for any use (severe or otherwise), and will take your engine to 100-150-200,000 miles just like a 30wt can.

 

[Curious Kid]

From the angle of the concerned but not fully in the "know", I think it's safe to say that one would fall back on the familiar. For some that would mean 30 or 40 weights from a particular or range of suppliers, over however long an OCI while using a similarly selected filter. That's not to say the formulations, designs, or state of operations haven't changed.

Without facts...experience, belief, and what provides that warm fuzzy feeling of confidence goes, which could end-up being counter productive. How much do we really know about the engines in our vehicles - actuals, not general (e.g.-coolant/oil flow and thermal transfer rates, expansion rates and clearances through the warm-up cycles, thrust loads vs. output numbers, etc.). How much reserve is there built into the management system(s)?

With all the variables involved, compromise is inevitable. With that, where are you willing to compromise? - not that things won't last longer, but without knowing those asking the questions just won't know.

Take care.

 

[chevrofreak]

I joined BITOG years ago, but never really got serious about oil until the last year or so.

My 96 Crown Victoria has been using a lot of oil, so I had purchased a jug of Pennzoil 10W-40 High Mileage to run in it, hoping that would cure much of the problem. Prior to that I had been feeding it 10W-30, because that's why dad used in everything.

Before I ever got around to pouring it into my engine I found out that Ford recommends 5W-20 for the 4.6L engines, and so I switched to 5W-20 and have been running it ever since. And I have been running the car just as hard as I did before. I haven't killed it yet.

The thought of running a 5w30 or 10W-30 in my car now just makes my stomach turn.

I'm glad I didn't have many preconceptions to get over to realize that 20's are great.

 

[ToyotaNSaturn]

With SJ & many SL oils, 30 grade oils sheared back the 20 grade range in a hurry (your CAFE comment here). This effectively makes a vehicle that has a lifespan with 20 grade oil. In light of this, it gives us more thinner oil comparisons than we may have originally thought.

My own car, the old '96-er
Pennzoil 5w-20 SM Conventional 7300 mile OCI, 174,000 total miles
M1 0w-20 SL 5400 mile OCI, 161,000 total miles

 

[Smokescreen]

so does the car still consume oil?

ToyotaNSaturn:
I appreciate the link to the UOA using a 20wt. Some good numbers there. I noticed it had a diet of 30wt previously. Are there any out there that have used 20wt since new out to 100-150-200,000 miles, or is it just to early to find a car with that many miles on it?

 

[BrianWC]

I think it's also an related to the fact that 5 and 10W30 are such ubiquitous oils and have been the standard oil in so many cars for a while. And you can still go into any gas station or discount store in the US and find a bottle of 10W30 on the shelf. It's engraved in peoples' heads that anything less than that is really thin.

 

[demarpaint]

Originally Posted By: chevrofreak
I joined BITOG years ago, but never really got serious about oil until the last year or so.

My 96 Crown Victoria has been using a lot of oil, so I had purchased a jug of Pennzoil 10W-40 High Mileage to run in it, hoping that would cure much of the problem. Prior to that I had been feeding it 10W-30, because that's why dad used in everything.

Before I ever got around to pouring it into my engine I found out that Ford recommends 5W-20 for the 4.6L engines, and so I switched to 5W-20 and have been running it ever since. And I have been running the car just as hard as I did before. I haven't killed it yet.

The thought of running a 5w30 or 10W-30 in my car now just makes my stomach turn.

I'm glad I didn't have many preconceptions to get over to realize that 20's are great.


Interesting you bring this up. I am have been using 5w30 in my 163,000 mile, 93 Aerostar for a long time, and use about 1/2 qt in 1700 miles. I am about 700 miles into the A-Rx rinse phase and plan on trying 5W-20 next OC. Ford has back spec'd this engine to use a 5W-20, and I do believe they are onto something here with the thinner oils.

I keep very accurate maintenance logs and did try a 5w30 15W-50 mix, 4 qts 5w30 and 1 qt 15W-50, and the oil usage increased. I doubt the 5W-20 is going to hurt anything and will probably help. Time will tell.

Frank D

 

[vranasaurus]

We all get into habits and form opinions based on past experience or knowledge and often times we don't adjust ou ropinions base dupon new information. I am probably as guilty as anyone.

I use 5w30 in everything I own. Even though the 1998 dodge stratus calls for 10W-30 I put in 5w30.

The wifes 2006 scion XA was originally spec'd for 5w30 from the factory but Toyota now says to use 5W-20 in the car. I am thinking about switching it to 5W-20.

I've used a 5w30 in everything I have ever owned and it's just a habit. This site has definitely opened me up to new ideas.

 

[XS650]

Something else to keep in mind is that xW-20 weight oils are usually thick 20s and xW-30 oils are usually thin 30s.

Going from your average xW-30 to your average xW-20 is more like changing 1/2 an SAE viscosity grade than a whole one.

 

[chevrofreak]

Originally Posted By: Smokescreen
so does the car still consume oil?


Yes, but it appears that most of it is going through the PCV system. The oil separator I added is preventing most of it from being burned, but it's still wasting the oil. It's possible that the separator adding some restriction to the PCV system will prevent much of the oil from ever entering the hose, so the amount I capture may not be directly related to the pre-installation consumption rate. I check the oil practically daily to keep an eye on consumption levels, and although I only have 200 miles on it since the installation I have seen very little change in the crankcase oil level. I'll be happier to know that the oil was going through the PCV system instead of leaky seals or piston rings.

 

[demarpaint]

Have you tried adding some MMO or TCW-3 oil to the gas. If it is a ring problem that might help increase compression by making a tighter seal between the rings and the cyl wall? Just a thought.

Frank D

 

[chevrofreak]

I've used MMO, ST TC-W3 and Lucas UCL. They did nothing for consumption, but they do make the car run smoother. Auto RX doesn't seem to have done anything for the consumption either. That's what makes me think it's not the rings.

 

[Smokescreen]

so the weight of oil 20wt vs 30wt didn't really have anything to do with oil being consumed?

Just the year previously, my engine was spec'ed for 30wt oil (Toyota 1.8L). Due to its tremendous track record, I am reluctant to make the change even though says use 20wt. I plan to own the car unitl it dies, if it means getting an additional 50,000 miles out of it using 30wt vs 20wt, I will do it. I am currently running PP 5w30.

 

[battyice]

Originally Posted By: Smokescreen
so does the car still consume oil?

ToyotaNSaturn:
I appreciate the link to the UOA using a 20wt. Some good numbers there. I noticed it had a diet of 30wt previously. Are there any out there that have used 20wt since new out to 100-150-200,000 miles, or is it just to early to find a car with that many miles on it?



I remember this argument over on crownvic.net a few years back, people were scared to switch b/c of a lack of data. Finally the manager of a NYC cab shop spoke up and indicated that they had been using 5w20 in the crown vics since Ford spec'd it in 2001, the cars all had 250-275,000 miles when they were retired from service (NMT 3yrs due to NYC law) and still running good. That was enough to get me to stick with 5w20 in my Grand Marquis.