Doug Hillary

Hello,
this is the result of the tenth Used Oil Analysis (UOA) of the engine oil in my ‘89 S4, and it will be the last provided by me

The oil and filter were changed at this sampling point, after 5016 miles (8078kms) over twelve months. Exxon-Mobil's Laboratory OK'd the oil for continued use

I use Mobil's Delvac 1 5w-40 Heavy Duty (HDEO) commercial diesel "mixed fleet" oil and it has the API's CH-4/SJ quality rating (whilst it has now been updated I am still using the older version). It far exceeds the ACEA's A3/B3-04 requirements. It has ACEA's E3, E4, E5 & B4 Certification for severe diesel engine standards of high turbo-charger boost pressures, deposit control, heavy piston and bearing loads, elevated heat and extended oil drain intervals. Being dual rated (diesel/petrol) it is most suitable for use in high performance petrol engines
Although NOT Porsche Approved it FAR exceeds Porsche's original quality recommendations for the 928 and their current Approval regime as well
This oil is now officially recommended for the 928 by Mobil in the US and is also marketed there as M1 T&SUV 5w-40

Using higher viscosity oils than are absolutely necessary to meet the expected ambient range in your area should be avoided in any 928 engine

Details:
Car - MY89 - 928S4 Auto
Speedo - 90150 miles (145168 kms) now
Oil - Mobil's Delvac 1 5w-40 fully synthetic HDEO - API rated as "CH-4/SJ"
Oil & filter change date - 14/09/04 (OEM "MANN" filter used)
Distance since Oil & filter changed - 5016 miles (8078 kms)
Oil used since 14/09/04 - nil (still at "FULL" mark)
Date of this sample - 16/9/2005
Distance since last sample - 1547 miles (2491kms)
Use in this period - 5% town, 12% urban, 83% highway
Avg speed in period - 42 mph (68 km/h with highest speed of 220km/h)
Fuel economy in period - 12.1 ltrs/100km
Ambient in this period - +42C high to -2C low
Humidity in this period - 98% (highest)

Oil Condition;

Viscosity OK - 89 (excellent) [90]< Average of all at Oil change
Water OK - 0.08%
Soot Index OK - 0.00
Sodium OK - 3
TAN OK - 3 (excellent - lowest is best, max allowed is 9)

Lab. UOA Report Summary;

ExxonMobil's rating now "Normal"
Translated status "Excellent - suitable for continued use"
Last Report "Normal"

Elemental (& wear metal) Analysis;
Details of the following columns;
Col 1- this UOA result in ppm (my comments are in brackets)
Col 2 - [?] rounded average of all UOA results at oil change

Iron 14 (excellent) [11]
Aluminium 5 (excellent) [5]
Chromium 1 (excellent) [1]
Copper 3 (excellent) [4]
Lead 5 (excellent) [8]
Silicon 4 (excellent) [5]
Sodium 3 (excellent) [5]
Tin <1 (excellent) [NA]

SPECIAL NOTE: The averaged figures are a good baseline for any 928 owner to use!

NOTE 1: General summary

The UOA result is typical of the previous nine UOAs and is therefore normal. Although iron is a little higher, this UOA's other elemental wear metal readings are at or below the previous averages for this engine and well below Industry acceptable limits. One Techron Concentrate fuel treatment has occurred since the oil change in September 2004 but no evidence of this appears in this UOA

The series of ten (10) UOAs indicate that the rings, pistons, bores, cams, cam, rod and crank bearings, crankshaft thrust washers and other major components are wearing at a very very low rate indeed

The testing to date justifies using the Porsche recommended (or better) oils and following their recommended servicing intervals despite what some so called Porsche "experts" may say in promoting shorter oil change intervals

NOTE 2: Engine oil performance observations (Delvac 1 5w-40)

It is interesting to note the following issues now that about 26000 miles (42000kms) have been spanned by the ten UOA's covering two different viscosity synthetic lubricants

A - Oil viscosity

A 5w-40 viscosity (the current recommendation) seems ideal for year round use in a 928!

B - Wear metals

The 5w-40 viscosity oil has certainly produced a downward trend in engine wear rates
It should be noted that wear metals will increase in volume (in ppm) as time goes by until drained with the oil - they are simply too small to be filtered out

NOTE 3: Current oil condition summary

The oil has performed very well and for those persons using Delvac 1 5w-40 in their 928 you have plenty of reasons to feel confident that you "caught the right tram"! The oil's viscosity is at near new and its ability to combat deposits and acids remain very high indeed

The oil (Delvac 1) and filter (MANN) were changed when the sample was taken
It is worth noting that by tracking both the oil's condition and the rate of wear metal(s) uptake the following data emerges;

a) the premium synthetic oil will last for at least two (2) years and probably three (3).
b) The Sodium "action" limit would be reached theoretically at around 90000kms
c) wear metal uptake rates indicate that the oil would last theoretically up to 80 000kms before any "action" limit is reached
d) the MANN oil filter will last for at least two years or 50 000kms

Even now with substantive "clinical" evidence to the contrary I do not advocate going beyond 12 months without changing the engine oil in a 928

I hope this is of value to some Rennlist people out there - there are now ten Used Oil Analysis results published that can be "trended" and used to monitor engine wear rates and the condition of the oil in their own car

Regards

FlyingDog

Excellent work. Thank you for writing this up.

Cameron

I have been reading each of your reports with great interest. I do appreciate the information.

Thank you for making the investment in time, energy and possibly $$ to do this.

BC

What is your opinion of this site:

http://theoildrop.server101.com/cgi/ultimatebb.cgi

BC

Any idea what German Castrol is and why it is so wonderful?

John Veninger

Thanks again Doug!

German Castrol (10W-60) is so wonderful because it's made in Germany

Doug Hillary

Hi,
I'm pleased to have been able to assist other 928 enthusiasts like me!

Brendan - the "BITOG site is excellent and has grown enormously since I joined in 2002 (in spite of me?)

As for the German Castrol (GC) they often discuss there - the following information I posted recently on our "924 and etc" Board may help;

"Hi,
yes, there are many formulation variances with Castrol (and others) as they become more Vehicle Maker specific

In durability field testing advanced formulation semi-synthetic oils in my heavy trucks for Castrol, I became an early user of the original German sourced Castrol SLX 0w-30 in 1996 in a variety of petrol engines. In its first formulation it was less than successful in some applications. After three formulation changes and subsequent blending in Singapore and Australia it was withdrawn from the Australian market in 2001(about). It was a sales flop!

1 - All Porsche Approved oils are either 0w-40 or 5w-40 viscosity (only one exception - Mobil 1 5w-50)

2 - "PAO" is Polyalphaolefin - a Group 4 "synthetic" basestock

3 - Many of Castrol's products are made from Group 3 "hydrocracked" basestocks. These excellent new technology basestocks (over the last three years) are cheaper than Group 4 and Group 5 (Esters) full synthetics. A Group 6 basestock exist too. Shell, Mobil and Caltex-Chevron-Havoline market excellent modern Group 3 formulations
Many perform at least as well as "full" synthetic Group 4 basestocks
Basestocks are made from only about five sources - Exxon-Mobil is the largest supplier. These end up in the "boutique" oils that you can pay lots of money for for no real benefit!

4 - The colour of new oil is usually from dyes. Shell Helix Ultra synthetic (Group 3) was a light purple

Castrol's 0w(or 5w)-30 viscosity oil of any designation is NOT Porsche Approved and Listed. All such oils from Castrol are either 0w-40 or 5w-40 viscosity

There are no "magic" oils no matter what the advertising may tell you. Porsche Approved and Listed oils from any Oil Company will perform about the same - be they Group 3, 4 or 5.

Oils that state that they "Meet" or are "Approved" for Porsche vehicles and are not formally "Listed" by Porsche have NOT been durability/quality tested by Porsche - I believe that this is VERY important

As a point of interest Castrol's 75w-90 GL5 synthetic gear oils and Transmax Z synthetic ATF are excellent in Porsche cars - they are probably the best around and at any price. I have run their 75w-90 GL5 gear oils at one million kilometer oil change intervals in my trucks with excellent results in seal, gear and bearing life!"
Ends

Gidday John - you and I both know how good Castrol's "R" synthetic 10w-60 really is!

Old & New

Doug,

Could you elaborate a bit on your point of avoiding oils with higher viscosity ranges than required by temperature. I use 20w-50 Castrol "GTX" to avoid excess consumption in my supercharged engine. All the valve seals are in good order, and I tend to use about a quart per thousand miles of spirited driving. I find my coolant to regularly run at 210F. The engine has 160K miles on it and I have found that lighter weight oil is consumed at an even more alarming rate.

John Veninger

Doug,
I'm pretty sure Mobil doesn't have a 5w-50, it's a 15w-50 in the states. Castrol Syntec is a 5w-50. Syntec also comes in a 5W-40. Was mainly marketed towards VW.
Yes the Castrol "R" synthetic 10w-60 is great stuff, but you pay for it! Mainly available at the local BMW dealer in the US.

I have 6qts of 0w30 SLX if anyone in Northern Alaska needs it

Dark Blue

I've always used Mobil 1 15W-50 in my '89 S4. Should I be looking at a lower viscosity oil? I live in Alabama where it's usually hot. Thanks.

Steve

Doug Hillary

Hi,
Old & New - Firstly, Castrol GTX 20w-50 is still the most popular mineral oil sold in this country and is used mainly in old technology engines. Sold cheaply in Supermarkets etc. it is a good product - for what it is!
The first 20w-50 oil was developed in 1958 by Duckhams for the Austin/Morris Mini and Castrol's version followed in 1959. Castrol's GTX 20w-50 was still a Porsche Approved and Listed oil in 1992 in NA

The '89 S4's Handbook listed a API SE/CC 20w-50 mineral oil for use from -10C to 40C+. It also listed a API SE/CC Group 3 synthetic 5w-40 oil for use year round in a temperature range from -30C to 40c+ .

Since 1989 there have been six API mandatory oil Quality formulation changes (SE to SM). In 1996 ACEA (the joint Euro manufacturers Technical Body) began Quality regulating oils. They have had at least four mandatory oil re-formulations up until 2004

The 5w-40 Group 3 synthetic oil recommended by Porsche in 1989 would fail all of today's quality tests and has been replaced by some wonderful products. This is no doubt why Porsche retrospectively revised its oil recommendations in 2004 all the way back to MY73 and in the narrow viscosity band we have today
This has made the 20w-50 mineral oil technically redundant for our cars where a rapid oil flow from cold and much better flow and temperature transference hot has many benefits

Castrol's mineral GTX 20w-50 (Col 1) and synthetic M1 15w-50 Col 2) are compared below;

Pour point : -27C # -45C (lower is better)
Viscosity @ 40C : 159 # 89 (lower is better)
Viscosity @ 100C : 17.6 # 17.4 (regulated band)
Viscosity @ 150C : 4.5 # 5.11 (Porsche's minimum is 3.6)
TBN : 6.3 # 11 (higher is better)

This data does not show the much better/more linear flow characteristics or high temperature tolerance of the synthetic lubricant - it does show the "stronger" oil film at 150C. An indication of the better low temperature (up to around 70C) of the synthetic is shown in the better pour point and the lower viscosity at 40C

So, Castrol's GTX 20w-50 is an average mineral oil. Their Syntec 5w-50 (as mentioned) by John or M1 15-50 are much better products for our cars if you want to stay with an SAE50 oil
A modern 5w-40 Approved synthetic will perform even better than both of them!

Your oil temps are normal and your oil consumption better than Porsche's max of 1.5ltrs/1000kms. M1 15w-50 may reduce your oil consumption!

John - Mobil sell M1 15-50 in the US. It is sold elsewhere too but as a "specialist" or MC oil. In all other International markets (perhaps in Canada too) it is only sold as 5w-50 (Porsche Approved)

Dark Blue - many 928 owners use M1 15-50 with very good results - it is a great product. I used a similar oil - Shell's Helix Ultra synthetic 15w-50 - in mine for about a year (see "Oil Condition Reports No 1 to 4" on here)
Marc (Devek) produced a chart some year or so ago that showed that even with M1 15w-50 (which has excellent flow characteristics) the system was still in by-pass after about nine minutes

The change to Delvac 1 5w-40 certainly made my engine run much better and I live in the tropics. This has been the same result for most OZ 928 owners too

Regards

Dark Blue

Doug, thanks for very informative advice. I'll see if I can source some synthetic 5W-40 here in the U.S. If I can't find synthetic 5W-40, would it be better to stick with the Mobil 1 15W-50 or switch to Mobil 1 5W-30 which seems readily available. I can't even remember what the second number means. I don't drive my '89 S4 hard, and it has relatively low mileage (67,000). Thanks again.

Steve

John Veninger

Steve,

5w-40 is pretty easy to find along with 5w-50 in the US.
5w-30 is to thin, 5w-40 is much better.

CWO4Mann

Here is a source and a possible group purchase opportunity for us:

http://store.avlube.com/fonfacsizcol.html

Cheers,

FlyingDog

Dave, you can buy Mobil T&SUV at Walmart for $21 for 5 quarts. It's the same stuff in a different package for less money.