Another oil question

[Tom NJ]

Originally Posted By: ADFD1
Does oil compress?


Non-Newtonian oils compress, which includes most multi-grade oils. The VI Improvers are very large molecules which will compress under pressure (temporary shear instability) and can break into smaller molecules (permanent shear instability).

This temporary loss of viscosity due to high shear rates is common in the main bearings, which is why the HTHS (High Temperature High Shear) test was developed using the temperatures and pressures found in bearings. This test looks at the remaining viscosity after the VI Improvers are compressed, and specifications are set to assure the remaining viscosity is adequate to separate metal surfaces and minimize boundary friction.

In a given set of operating conditions, there is an "ideal viscosity", that is, a lower viscosity could collapse the oil film and increase friction & wear, while higher viscosity creates drag and wastes fuel. Under normal driving conditions in a well maintained engine, the manufacturer's recommended oil grade will provide sufficient protection with respect to the oil film. In abnormal conditions, such as very hot weather, pulling heavy loads, racing, poor maintenance, cooling system malfunctions, low oil levels, engine misalignments, etc., a slightly heavier oil with a higher HTHS viscosity can provide added protection.

When it comes to recommending an oil grade, car manufacturers need to balance engine durability (warranty claims and reputation) with fuel efficiency (CAFE fines and selling point). Personally I don't trust that they always place durability high enough, so I tend to use slightly higher viscosity oils as insurance against the unexpected. That said, engine failure due to oil related wear is extremely rare, and one could argue that I am wasting a little fuel, but I view $5/yr as pretty cheap insurance.

Tom NJ

 

[Mark888]

Many dealers will use 5w30 on oil changes even when the car specifies 5W-20, so they don't have to stock multiple different viscosities in bulk (and they have to do some oil changes on older cars that need 5w30). Now if the car "requries" 5W-20, that may be a different story, but many (not all) cars that specify 5W-20 on the oil filler cap will tell you in the owners manual that 5w30 is OK.

Some dealers will only carry synthetics in 5w30, even though they buy it in bottles. Obviously I am not talking about German cars which require a specific synthetic oil that is 0W-30, 0W-40, etc.

 

[ADFD1]

Thanks for the replies. As you can tell I'm fishing for knowledge here.

Thanks for the explaination on how oil can compress because of viscosity improvers, that cleared things up.

What is still confusing is how an engine in 2005 or 2006 that had undergone no changes is now spec'd for only 5W20 in 2007 and no other oil choices mentioned in the OM, for any and all climates, towing included. I'm almost inclined to believe there is a hidden adgenda? Conspiracy theory..lololol.

 

[Johnny]

It's really pretty simple. The federal government has required the auto manufactures to meet certain overall fuel mileages CAFE (Corporate Average Fuel Economy) for all of the thousands of vehicles they sell. We will just use Ford as an example. They use to list different vis requirements according to different outside operating temps. The car that ran on 5w30 would get better mileage than the car that ran 10W-40. Not by much, but a little. Ford did some extensive testing back in the 90's and found engines would be protected with a 5W-20 in all conditions, and produce a slight mileage advantage. So they recommend 5W-20 in almost everything they make to help bring down the mileage in all of the vehicles they make in order to meet the overall (government enforced) CAFE. If the manufactures do not meet this standard there are some pretty hefty fines given to them.

 

[ADFD1]

Has Ford or Chrysler changed engine bearing tolerances or cyl tolerances from 2006 to 2008? They seem to be the two domestics specing 5W20 more so than the others.

For instance chrysler 3.7L. Or is the engine identical from 2006-2008 except for maybe some emission tweaks?

 

[Johnny]

Not that I'm aware of.

 

[Gary Allan]

Originally Posted By: ADFD1
Has Ford or Chrysler changed engine bearing tolerances or cyl tolerances from 2006 to 2008? They seem to be the two domestics specing 5W20 more so than the others.

For instance chrysler 3.7L. Or is the engine identical from 2006-2008 except for maybe some emission tweaks?


For all we know it just took that long to complete validation on their 5w-20 longer term testing. They found whatever issues arose out of the use of 5w-20 oils were in fringe areas that were far outweighed by the benefit or lack of liability in the vast majority of its usage.

..but I'm still waiting for a larger segment of the newer cars showing issues before 15 years of service and have engine fatigue being a major player in the ultimate retirement of the chassis. While only 7 years has expired since the spec'ing of 5w-20 ..and regardless of if a 5w30 was used by most of them after some warranty period, the alleged "fear factor" effects would be apparent in any practical shortening of the end of life event ..which still never occurs for 99% (pulled out of the rhetorical air number) of the rolling fleet.

 

[ADFD1]

What sux is being a guinea pig. That is the people who buy cars and keep them well past the normal time to retire a vehicle. Interesting stuff at any rate, thanks for the great replies and warm welcome. I should have started posting a long time ago instead of just reading here!!!

 

[Tom NJ]

Always keep in mind the car manufacturer's financial drivers. They certainly want an engine to last through the warranty period as repairs are real money, so 3-5 years life is a must. They also want to maintain a good reputation since that affects sales, so the engine should last up to say 8 or 9 years as well. After a car is 10 years old, however, few people would blame the car maker for a blown engine, after all the car is old and perhaps wasn't well taken care of. Only the fringe car buffs would notice such a trend, and they are a small percentage. That's not to say car makers don't care about the car buffs, but a new driver starts to come into play at around 8-10 years, which is they would really like you to buy a new car.

I'm not saying all car makers aren't trying to make the best engines they can, only that they have financial drivers that create a disincentive to do so.

Tom NJ

 

[D189379]

Originally Posted By: Triple_Se7en
My switch to 20 weight in my S-10 4.3 engine produced a smoother running engine with better gas mileage. But the downside scared the beegeevers out of me. The magnetic oil drain plug was overloaded with metal shavings using Quaker State Synthetic for 5K. I never had metal shavings prior with 5w30 and haven't had any shavings since the switch back to 5w30.


I would think all that metal to metal contact would result in lower gas mileage?

 

[ADFD1]

Originally Posted By: Tom NJ
Always keep in mind the car manufacturer's financial drivers. They certainly want an engine to last through the warranty period as repairs are real money, so 3-5 years life is a must. They also want to maintain a good reputation since that affects sales, so the engine should last up to say 8 or 9 years as well. After a car is 10 years old, however, few people would blame the car maker for a blown engine, after all the car is old and perhaps wasn't well taken care of. Only the fringe car buffs would notice such a trend, and they are a small percentage. That's not to say car makers don't care about the car buffs, but a new driver starts to come into play at around 8-10 years, which is they would really like you to buy a new car.

I'm not saying all car makers aren't trying to make the best engines they can, only that they have financial drivers that create a disincentive to do so.

Tom NJ


I like the way you think.

I always thought less friction, lower drag, means lower wear, seems that might be flawed thinking?

 

[Peter_Pan]

Originally Posted By: Tom NJ
Always keep in mind the car manufacturer's financial drivers. They certainly want an engine to last through the warranty period as repairs are real money, so 3-5 years life is a must. They also want to maintain a good reputation since that affects sales, so the engine should last up to say 8 or 9 years as well. After a car is 10 years old, however, few people would blame the car maker for a blown engine, after all the car is old and perhaps wasn't well taken care of. Only the fringe car buffs would notice such a trend, and they are a small percentage. That's not to say car makers don't care about the car buffs, but a new driver starts to come into play at around 8-10 years, which is they would really like you to buy a new car.

I'm not saying all car makers aren't trying to make the best engines they can, only that they have financial drivers that create a disincentive to do so.

Tom NJ


I'm sorry Tom but I think engines in modern cars last a lot longer than they used to. Just look at the warranties out there! Chrysler has the lifetime powertrain warranty in place (Although whether or not they can outlive their cars is another story) and many other manufacturers have 10/100K warranties in effect.

Also the PZEV 15/150K warranty that covers a all of the emission components (I'll add a list of components later tonight) have been around a couple of years now. Although this warranty does not directly cover the moving parts of an engine, for the emissions systems to perform correctly the engine obviously needs to be working properly and it's in the manufacturer's best interest to design the moving parts to at least outlive the emissions parts.

I think PZEV cars will be on the road a lot longer than before. I know I plan on keeping my PZEV Lancer around to the 15 year mark as I don't put much mileage on it. That would be a whopping return for the 14K I paid for the car!

 

[demarpaint]

I agree and own a Chrysler. I don't believe that many people will actually benefit from the LT Warranty, and not because Chrysler might go belly up.

In order for that warranty to be in effect 6 months before the 5th year of ownership you bring the car in for a free inspection. They will come up with a list of things that have to be done in order to preserve the warranty. According to what I was told by a service mgr buddy the work will have to be done by an authorized Chrysler Dealer to satisfy the warranty requirements. It won't be cheap. Then if the car changes hands all bets are off.

Since no one has gone the 4 1/2 years since this warranty was issued no one can really dispute it. My bet is it is/was a selling tool, and will be a tool to generate service revenue, even from the DYI'ers. JMO

 

[Tom NJ]

I agree modern engines last much longer than older ones, but I believe this is due more to better design, manufacturing technology, and metallurgy than better oils. But warranties are a different matter. A car with a longer warranty is not necessarily built better, nor will it necessarily live out the warranty. A long warranty is just an insurance policy, paid for by the higher sales it brings.

My point is simply that car manufacturers have incentive to take a bit more risk with engine durability in the name of fuel economy and current sales.

Tom NJ

 

[buster]

Engine durability tests vary by manufacturer too.
http://www.allpar.com/mopar/new-mopar-hemi.html

Some of the engine durability testing Dodge put the Hemi through was more severe than most people could replicate.

Quote:
Testing included 11 million customer equivalent miles, with stronger durability testing than any previous Chrysler engine. The 7 year/70,000-mile powertrain warranty is backed by 11 million customer equivalent miles (CEMs) of testing, including more than 200,000 CEMs of durability testing for the average consumer - more than any other Chrysler engine. The battery of reliability tests closely represents real-world driving conditions, in some cases exposing the engine to more severe abuses than drivers can dish out. For example, during a 260-hour period, the 5.7-liter HEMI was repeatedly heated to 240°F and then slammed with coolant that was -25°F.

"The engine was exposed to some of the harshest testing conditions and abuses imaginable," said Donald Dees, Vice President of Quality for the Chrysler Group (and formerly of Toyota, so you know that means something).

Quote:
In our duarability test cycle (150,000 customer equivelant miles driven at the 95 percentile, meaning that only 5 percent of our owners are more abusive than our testing), we have not found any adverse wear patterns." (Chrysler PR materials boasted of “over 6.5 million customer-equivalent miles through development and durability testing.”)


As an engine ages, it wears and over time moving up a grade is often necessary to reduce blow by. Many people are getting 150k miles out of their engines using nothing but a 5w20 oil.

The one thing that has not changed over the years is the max. low HT/HS of 2.6. All 20 grades are at or above that.

 

[Tom NJ]

I don't doubt that a performance engine will be designed for higher durability. Nor do I doubt that ordinary engines are built to be reasonably durable. The question is the balance between durability and fuel economy.

I simply believe CAFE is driving the car makers toward the thinnest oils that will "work", that is, keep the engine alive for 8-10 years, and their priorities are different than mine. The extra 0.5-1.0% fuel economy that a 5W-20 may deliver is very important to them with respect to CAFE fines, but meaningless to me.

Tom NJ

 

[buster]

I agree. There is definitely a balance between the two.

I'm impressed with how reliable and trouble free most cars are today. They are practically maintenance free other than oil/tires/basic stuff.

Mobil 1 0w30 has a HT/HS of only 2.99. This oil still manages to meet GM's 4718M too. Decent in between choice.

 

[zrxkawboy]

Originally Posted By: Tom NJ
I don't doubt that a performance engine will be designed for higher durability. Nor do I doubt that ordinary engines are built to be reasonably durable. The question is the balance between durability and fuel economy.

I simply believe CAFE is driving the car makers toward the thinnest oils that will "work", that is, keep the engine alive for 8-10 years, and their priorities are different than mine. The extra 0.5-1.0% fuel economy that a 5W-20 may deliver is very important to them with respect to CAFE fines, but meaningless to me.

Tom NJ


Very well stated, Tom!

 

[buster]

http://www.sae.org/servlets/productDetail?PROD_TYP=PAPER&PROD_CD=1999-01-3468

Quote:
Author(s):
Hideki Tanaka - Honda R&D Co., Ltd.
Takashi Nagashima - Honda R&D Co., Ltd.
Takashi Sato - Honda R&D Co., Ltd.
Syouji Kawauchi - Honda R&D Co., Ltd.

Abstract:
We at Honda have been striving to develop fuel-efficient engine oils and applying them to models to have more and more fuel saving automobiles. To be more specific, the improvements have been done for mineral oil with High Viscosity Index (hereafter referred to as HVI) base oil. Our study with HVI base oil has continued and eventually led to development of a SAE 0w20 grade engine oil that provides additional fuel savings. It showed a fuel economy improvement of 1.5%. Due to concerns about abrasion resistance and oil consumption related to the reduced oil viscosity, vehicle testing was conducted. That testing demonstrated these problems did not occur.

 

[demarpaint]

Originally Posted By: Tom NJ
I don't doubt that a performance engine will be designed for higher durability. Nor do I doubt that ordinary engines are built to be reasonably durable. The question is the balance between durability and fuel economy.

I simply believe CAFE is driving the car makers toward the thinnest oils that will "work", that is, keep the engine alive for 8-10 years, and their priorities are different than mine. The extra 0.5-1.0% fuel economy that a 5W-20 may deliver is very important to them with respect to CAFE fines, but meaningless to me.

Tom NJ


Very well said Tom, and there might be more truth to that statement than a lot of us want to believe, myself included.