Doug Hillary

Hi,

This is the fourth and the final Oil Condition Report concerning the oil in my car - at approx. twelve (12) months and at the oil change point

The Used Oil Analysis ( UOA ) commenced nine months ago - the oil had been in the engine three months then. It was undertaken to confirm Porsche's original oil change recommendations for the 928 - namely, 20000kms or 12 months for "normal" use
The engine oil is now at the maximum time limit set by Porsche, not the distance limit
Used Oil Analysis is used by Equipment Manufacturers, Fleet Managers and Race Teams worldwide. The standardised testing processes compare the original ( virgin ) oil's composition alongside the used oil sample. I have been involved with this process since the late 1960's

The oil and filter were changed at this sampling point even though the ExxonMobil report OK'd the oil for continued use

It was my call to change it out now as it follows Porsche's prescribed maximum time limit

Details:

Car - MY89 - 928S4 Auto
Speedo - 117084kms ( 72709 miles)
Oil - Shell Helix Ultra full synthetic 15w-50 - SJ/CF**, A3-96/B3-96
Oil/filter change date - 10/17/02
Distance since Oil/filter changed - 13569kms (8426 miles)
Oil used since fill - nil ( level only 200ml down = total volume of all samples )
Date of this sample - 10/07/03
Distance since last sample - 2236kms (1388miles)
Use in this period - 16% town,40% urban,44% hiway
Avg speed in this period - 71 km/h ( 44mph)
Fuel economy in this period - 11.7ltr-100km (24 mpg Imp) ( 20 mpg US )
Ambient in this period - 28c high to -2c low
Ambient - annual historical averages - 27.5c max. & 21.5c min.
Ambient - actual in 12 months - max. 40c & min. -2.5c
Humidity in this period - 96% highest
** This oil has a later "rating" than in the 928 S4's Handbook - technology has moved on since 1989. It is not the very latest API oil rating - SL/CF ( and A3/B3 ) - which should perform even better than this oil did over the time and/or distance limits!

Oil Condition - "use" factors;

Note - report figures below are shown thus: now-3-2-1(1=first sample)

Viscosity OK - 98-98-98-94 ( excellent )
Water OK - 0.06%-0.05%-0.01%-0.00%
Soot Index OK - 0.00-0.00-0.00-0.01
TAN OK - 3.8-4.6-2.6-3.2 ( excellent ) the Max allowed is 8.9

Lab. Report Summary

ExxonMobil's rating now - "Normal"
Status-Excellent for continued use
Last Report - "Normal"

Estimated oil's lifespan left until change required - 24500kms ( 15200 miles )
Estimated total of oil's lifespan - 38000kms ( 23500 miles )

Elemental ( & wear metal ) Analysis;

Industry "acceptable" rates (range rounded) - not 928 specific - shown as ((?))
My engine's averages are shown as [?]

Iron 10-9-7-6 ( excellent ) ((30-100)) [ 8 ]
Aluminium 4-3-2-3 ( excellent ) ((5-30)) [ 3 ]
Chromium 1-1-<1-1 ( excellent ) ((1-30)) [ 1 ]
Copper 4-8-5-3 ( excellent ) ((10-30)) [ 5 ]
Lead 7-7-4-4 ( excellent ) ((40-100)) [ 5.5 ]
Silicon 5-5-11-22 ( excellent ) ((10-30)) [ 10.75 ]
Sodium 6-2-2-5 ( excellent ) ((8-10)) [ 3.75 ]

Note:

None of the elemental "movements" have ever been significant. All are at or well below Industry acceptable figures. This indicates that rings, pistons, bores, cams, bearings and other major components are wearing at a very low rate

Oil Condition Summary:

The oil itself has survived for 13569kms ( nearly 8500 miles) and nearly twelve (12) months very very well. The oil's degradation has been very low and its ability to fight acidic corrosion is better than many new cheaper oils. It's viscosity has remained exceptionally close to the original new "virgin" oil - virtually no thicker or thinner than at the start 12 months ago
On the oil's condition readings alone, it could have been left in for another extended period of use. This is but one advantage of a good quality synthetic lubricant

UOA Test Results Summary:

Porsche's Handbook recommendations for normal use are hereby confirmed by the UOA and with a big margin too!! Newer specification oils either mineral or synthetic, will extend the margin still further
Like everything else, time has "moved on" and so has the quality of the oils we can readily purchase today. There has been about five quality upgrades since 1989 alone!!

As a result of the UOAs, the engine has now been put on to Mobil's Delvac 1 5w-40, a lighter viscosity Heavy Duty commercial diesel oil. This oil is the very latest rated diesel oil - API CI/SL - it also exceeds ACEA's A3 and B3 ( E3,4,5 & B4) and is suitable for high performance petrol engine vehicles too. It will stay on this oil as I have good access to this product - it is also used in my heavy and light trucks - and in my other cars too

It will be argued by some ( and indeed already has been here ) that my car gets an "easy life" - I accept that I am probably rated as a smooth and sensible Driver. I was in volved Prototype Vehicle Development including Test Driving many years ago and by experience/knowledge do not abuse my vehicles - but I always know their limits!
I would say that my car is treated close to the way the average 928 owner treats their vehicle.

According to our "Landsharkoz" information, the ownership profile of the 928 is 95% male and aged in the 45-50 range. 57% are self employed and own two or three other cars.
I'm about an "average" owner/user then, just a bit older and I own more cars! And I drive about 40000 miles per annum

I hope this is of interest

Regards

Lagavulin

Extremely so, thanks for the good post!

Nicole

Thank you for putting science over religion! I am just wondering, why you changed the oil, if it was still in such good condition...

Old & New

Doug,

Thanks for the good work. It has benefited all of us. If Delvac is not readily available, what would you recommend?

I don't suppose you could get some good hard data on antifreeze and water pumps...

Gretch

Adding my thanks also Doug............... so much for religion..

Jim bailey - 928 International

Doug thanks for putting so much hard data up against the URBAN MYTH that changing oil every 3,000 miles is a good thing ! It is a waste of time , money and natural resources (although that "used oil" gets recycled ) . There is no proof that frequent oil changes and less engine wear are related it is typically an act of faith ............or the result of a lot of misleading advertising / recommendation's by people who sell oil changes ! So once again Porsche knew what they were doing recommending 12 months -15,000 miles for oil changes ...... Surprise ???

Doug Hillary

Hi,
Thanks for the comments

Nicole - I just felt that after 12 months the oil should go. I suppose the twelve months limit is "sensible" for most people with the oil changed in the Spring. The oil that came out of my engine was in unbelievably good condition going by the final UOA and is a testimony to the engineering that went into the 928's engine systems. And to their conservative recommendations in Porsche's Driver Handbook
As you are probably aware, some Euro makers ( Opel, VW etc. ) are now recommending 40kkms and two year oil change limits on certain cars/engines

Note: Mobil's Delvac "fleet" oils are made in both Mineral and Synthetic formulations and formulated especially for diesel engines

The Mobil Delvac 1 5w-40 oil I am using now is a fully synthetic CI/SL oil
and by all accounts is difficult to obtain retail in the USA. It is not sold in retail outlets in Australia but it may be available in some Mobil Truck Stops

Note: As to a brand of oil well it is still really a personal religion with many people. The oil's maker should be well known and the oil the correct viscosity for your area. Its container must be marked with the API's SH>/CF> and ACEA's A3/B3 ratings APPROVALS. If so, it will meet the Porsche standards required for engine durability and long life under normal driving conditions - in Mineral or Synthetic form. Ideally, it may also have "Porsche Approved" and/or MB229.3 on its container too

A future edition of the "928Forum" magazine will contain an article on oils
and cover the subject in much greater depth

If anyone would like a copy of the single A4 page "Mobil Monitor" Lab. report covering all four UOAs sent to them please e-mail me direct

Regards

Jay Wellwood

Doug-

What an excellent report. Thanks so much for taking the time to persue this topic as well as sharing the results with us.

BarryW

Thanks Doug for that excellent report. Your time and effort is obvious and appreciated especially on this important and common topic. This information has the potential to save people a lot of money and time that can be better spent driving instead of crawling around under our cars unnecessarily...oh wait, I do that anyways.

Nicole

This whole story makes me wondering, if these 3000 mile oil change services might just be one large scam. Since the oil coming out of the engines is still like new, they might collect it and just put it into the next car that comes in - nobody would know...

Yes, Doug, I am well aware that the same oils last longer in all parts of the world excpet America, and therefore manufacturers in these parts of the world can have longer change intervals. Of course, I'kidding!

JPTL

Doug,
Wow. Talk about an observation based on fact, and not opinion. This one's a saver. Thanks for the time that you took to post such a comprehensive and interesting report.
A year or so ago, I picked up a case of Delvac Super 1300 15w-40 "The Million Mile Oil" at Costco. It was cheap, even compared to other mineral oils.
I got it to run in my high mileage Explorer...not my GT. The reason that I got it, was because it was cheap, & packaged in convenient 5 qt. jugs, and my Explorer, at 275k wouldn't know the difference.
Should I consider running this in my '99 5.0 Explorer instead of Valvoline or other minerals?
I'm not trying to divert this thread into an Explorer subject, but I'm wondering if this Delvac is worth picking up if I see it again.

Thanks again for the interesting post.

Doug Hillary

Hi,
JPTL - The high quality mineral oil you mentioned, "Delvac 1300 15w-40", is a very good product. It should be API rated as CH4/SJ - check the container. If so, it is most suitable for "long life" or maximum suggested OC intervals
It is suitable for your Explorer if the viscosity corresponds with the area you live in - down to -15C I believe but you should check your handbook

It would also do good service in a 928 subject to Ambient temperatures in the area of use

All disclaimers noted - fleet oils as long as they have an SH>/CF> rating are excellent products.

Many years ago Shell Rotella - a diesel oil - was THE factory fill at Porsche!

Regards

Randy_J

Doug, just a terrific report as usual! Thanks - I've cross poseted this onto the 944 / 951 forum.

tuk_928

Doug,
As a new guy here...I've heard much talk about your "Oil Condition Reports" and am happy to read your 4th installment. The 3,000-mile oil change became entrenched in the mind of the general public due to high-profile advertising campaigns, service-shop in-window service reminders, and ultimately urban legend about how this frequent service interval could prolong the life of the engine in one's vehicle.

Funny how in my BMWs and now in the 928s4 the recommended service-intervals were substantially longer (7k, and 10k, respectively if my memory serves me well).

Kudos for having the bravery to use your 89 shark as a test bed various oils and intervals. Thank you for sharing your observations with us...

Sincerely,
Tim

Normy

There is always someone around who says "What if....?"

First of all, I want to point out that I am in no way, shape, or form an expert on motor oils. I've used them for years and have had good results. And yes, up to this point, I've always changed my oil at 3000 mile intervals.

Perhaps its my aviation background, but I always think about subjects from more than one side [you know..."what if?"]. I think Doug Hillary has done an admirable job proving that 3k mile/ 5k KM intervals for oil changes are probably a bit too often. On his car....

That's my main point: Doug drives his car carefully, and it is probably a "cream puff" that has seen perfect maintenance and is in perfect condition. Many people who frequent this board probably have cars like his, but many do not. Be carefull....

There might be a lot of older cars here that have rings and bearings that are on the ragged edge of having too much clearance. One instance of overheating, lets say, and you no longer have decent oil protecting these well- worn parts. Suddenly there are clouds of blue smoke behind you and you discover that your mighty engine needs an overhaul. On older cars, it might be a better idea to change the oil at 3k intervals. Oil really doesn't break down- it looses its additives and gets contaminated with mileage. For example, a car with worn rings will have more blowby and is more likely to reach the maximum permissible water content in its oil than Doug's car. If it exceeds this amount, the weakened bearings could be damaged.

I'm probably going to stop changing oil at 3k intervals.

Be careful and think twice-

Normy!
'85 S2 5 Speed