Economy - Longevity - Performance
The #1 Source of TDI Information on the Web!
Forums Articles Links Meets
Orders TDI Club Cards TDIFest 2016 Gone, but not forgotten VAG-Com List Unit Conversions TDIClub Chat Thank You

Go Back   TDIClub Forums > VW TDI Discussion Areas > Fuels & Lubricants

Fuels & Lubricants Discussion all about Fuels & Lubricants. synthetic oil, conventional oil, brands, change intervals, diesel grades, gelling and such debated items like that. Non TDI related postings will be moved or removed. This forum is NOT for the discussion of biodiesel and other alternative fuels.

Thread Tools
Old November 23rd, 1999, 05:40   #1

The VW TDI holds 4.7 quarts of oil, figure that the oil weighs about 2 pounds per quart roughly so figure 10 pounds of oil per full crankcase. The very best oil filters have a loading capacity of about 20 grams of material. The majority of the solid carbonaceous soot molecules are below 10 microns (PM10) and the majority of these are below 5 microns (PM5), the majority of both of these sizes of soot particles are NOT filtered by the oil filter.
One pound = 16 ounces = 454 grams

If the total oil weight is 10 pounds and the maximum soot loading of the oil allowed by the oil analysis chemists is 3% maximum. Three percent of 10 pounds is about 14 grams of soot, one percent is 1/3 that amount. But since the majority of TDI oil filters have little to NO effect on the sub 10 micron solid soot particles, that means at the 3% level there is about 15 grams of soot floating around in the oil throughout the entire engine. Soot is an abrasive and combines with water and other combustion byproducts to form sludge and varnish, especially up around the piston rings and cylinders.
It seems to me that 15 grams of soot at the 3% soot concentration level is too much, ie NOT GOOD for the engine. Even if a standard filter handled the <10 micron sized particle, it would be loaded with soot at the 3% level. I think also that 3% soot raises the viscosity level of the oil at least 20% if not more.
  Reply With Quote
Old November 23rd, 1999, 06:01   #2
Ric Woodruff
BANNED, Ric went to Coventry.
Join Date: Feb 1999

Large particle soot is BAD (it causes abrasion to unacceptable depths, can clog oil passages and filters).

Small particle soot is GOOD (It helps polish the cylinder walls to a smooth, mirror finish to reduce friction).

I am planning on using the 3% number as a guideline for when to say when.

Ric Woodruff

Ric Woodruff is offline   Reply With Quote
Old November 23rd, 1999, 07:42   #3

Ric, you are totally incorrect again. The majority of damage and engine parts wear is attributed to soot particles in the LESS THAN 10 MICRON range, with 90% of the damage to the engine coming from the LESS THAN 5 micron range. It is simple to understand, however your information is wrong again.
  Reply With Quote
Old November 23rd, 1999, 07:44   #4
Ric Woodruff
BANNED, Ric went to Coventry.
Join Date: Feb 1999

Show me the evidence.
Ric Woodruff is offline   Reply With Quote
Old November 23rd, 1999, 07:49   #5

New Diesel Engines and Oils Require Better

Recent design changes in diesel engines include moving the rings closer to piston
tops (as VW did in their A3 and A4 TDI engines compared to earlier Audi designs! ). to lessen the quench volume or dead space in each cylinder. The
burn is more complete, but soot still
forms. Because of the high rings, more of the soot gets
into the crankcase.

Oils are different. we have lower solids content, to
reduce the ash formed during the burn. Lower ash
means lower alkalinity, measured as total base number
(TBN), the percentage of alkaline material in the oil.
That means less detergent. New oils have to hold
more soot in suspension, but with a lower detergent
content, the soot will not be as well disposed. Alkaline
additives also neutralize acids and without makeup oil,
more frequent oil changes could be needed.

New fuels will help. They will have less acid producing
sulfur and lower aromatic content. Cetane levels will be
improved for a faster, more complete burn. White
smoke on start-up will be reduced and warm-up time
will be shorter. This will reduce, but not eliminate, acid
formation and soot.

Soot Damages Engines

Soot is an abrasive form of carbon. Oil carries it into
critical engine parts. Bearings, cams, lifters, rings, and
gear trains all experience premature wear unless
soot is removed from the oil. But ordinary filtration won't
work on micron sized particles.

The best way to protect your engine from the
effects of soot is through ultra-fine filtration.
Ordinary filter media cannot remove particles that
do the most damage. Picture a filter as a screen.
Openings in the screen determine the sizes of
particles that can pass through. As larger particles
are caught the screen openings are blocked and
they become smaller, Filtering efficiency increases
as smaller openings catch finer particles, but flow is
reduced as the screen gets blocked. Eventually the
screen clogs, cutting flow entirely. A loss of all
lubrication would cause the engine to seize.

Full flow filters are required protection on all
engines. The filter is located after the oil pump,
before the oil galleries into the engine. All full flow
filters have pressure relief valves. During a cold
start, when there is high restriction, the pressure
valve opens to let unfiltered oil flow. The
manufacturer's theory is that a small amount of dirty
oil is better than no oil at all, especially during a cold

Full Flow Filters Can't Remove Particles
Causing Most Engine Wear

The newest full flow oil filters capture particles
down to 20 microns (a micron is 1/1000 of a
millimeter, or 0.000039"), but even finer soot
particles do most of the damage. Sharp, abrasive
carbon soot, dirt, and other impurities as fine as one
tenth of a micron can wear away metal parts in a hurry.
Particles in the one to ten micron range do most of
the damage. They are carried by the oil between all
bearing surfaces and rubbing components.

Full flow filters use special filter paper, pleated to
get more area in the cartridge. The paper is only a
few thousandths of an inch thick. Early unit-
removed 30 to 35 micron grits. Modern ones still
let through almost all die grits smaller than 10
microns. They get into clearances between bearings
and journals, cam lobes and lifters, rings and liners,
and into meshing gear teeth. To prevent abrasive
wear in these super critical areas, a better type of
filtration is needed; one that can remove these ultra
fine soot particles.

Bypass Filters Can Remove Smaller

There are two major differences between full flow
and bypass filters. First, full flow filters route all the
oil through the filter, while bypass filters send only a
small fraction of the oil picked-up by the oil pump
to the filter. The clean oil goes back into the
crankcase, effectively bypassing the engine. That is
why the filters are called "Bypass-type".

Although just a small portion is filtered on each
pass, within 30 minutes of engine operation, virtually
all the oil in a crankcase will be filtered. After an oil
change, clean oil doesn't have a chance to get
saturated with dirt and soot.

Second, bypass filters don't restrict oil flow in the
engine. They just clean better. Bypass filters can be
larger and finer than full flow ones. Modern bypass
filters force oil through
seven inches or more of tortuous travel in the filter
media. Most commercially available bypass filters
can trap particles as small as ten microns.

Engine makers recognize the benefits of bypass
filtration. Used in addition to, and not instead of a full
flow filter, it will not alter or void any engine
warranty. Bypass filters will be needed. Soot in
1998 engines is expected to be so bad that new filter
cartridges, combining full flow and bypass
technologies, have already been developed. These
are better than full flow filters, but they are
compromises. With both types of filters in one
housing, the volume of each is limited. The full flow
filter must be smaller, to make room for the bypass.
Bypass filter size is small compared to stand alone
units, so filter life is shorter. Combination filters arc
designed to be replaced between 8,000 and 12,000
miles, compared with separate bypass filters that can
last 25,000 miles or more.

Bypass Filters Are Needed to Remove
Engine Damaging Soot That Full Flow
Filters Cannot Trap.

The filter medium will make a vast difference in
bypass filter performance. Almost any form of
cellulose fiber will filter engine oil, but efficiency and
life are affected by the medium used, and how it is
made. Early bypass filters used sawdust felt, cotton
waste and even tightly packed wood chips.
Surprisingly, most performed better than full flow
filters, but they still didn't remove particles in the
critical zero to ten micron range. In a paper
delivered to the SAE (Society of Automotive
Engineers) in 1998, Needle man and Madhavan
made a Review of Lubricant Contamination and
Diesel Engine Wear (SAE 981827). They found that
full flow filters leave over 10,000 particles per cubic
centimeter that are five microns or larger. Of these,
ninety percent are in the five to ten micron range that
do the most damage. A diesel engine with 10 gallons
of oil can hold over 400,000,000 million potentially
damaging particles. Grits that pass through full flow
filters cause seven times more wear than those larger
than 20 microns can.

  Reply With Quote
Old November 23rd, 1999, 07:51   #6

Ric, this evidence blows your theories and hypothesis's out of the water, what a dive!
  Reply With Quote
Old November 23rd, 1999, 08:32   #7

Damn, even the BIG DEISEL RIGS are feeling our pain, especially in the new 1999 models:


Recalibrating engine timing to meet EPA changes is shortening oil drains.

The exhaust emissions EPA consent decree agreed to by U.S. diesel engine manufacturers last October may have significant implications on oil
drain intervals for big-bore diesel engines produced after Jan. 1 and used in over-the-road applications.
That was the consensus of Caterpillar, Cummins, Detroit Diesel and Mack experts speaking last month at the annual meeting of The Maintenance
Council of the American Trucking Assns. in Nashville.
While slight reduction in fuel mileage may show up in some engines’ horsepower rating, it’s likely to be less than 1/10 mpg. In most cases, fuel
mileage will be the same as in ’98 model engines.
For trucks and tractors used in urban/suburban driving where engine electronics/timing stay in the EPA urban test cycle mode most of the time,
there are no changes, according to Bob Wessels, product process manager for Caterpillar. It’s only in sustained open-road driving when the engine is
called on to put out higher power that the recalibrated electronics could affect mileage.
Retarding timing to get NOx down to 6 grams hp/hr. in highway mode is what’s potentially affecting oil contamination. With injection after top dead
center, some unburned fuel in the form of soot is deposited on the upper cylinder liner walls where the piston rings scrape it down, adding more soot to
the crankcase oil. It’s this increased soot that concerns the engine companies and, for that matter, the oil companies because oils now have to deal with
much more of it.
As a rule of thumb, engine manufacturers on their big-bore ’99 engines have cut their oil drain recommendations about 20% from 1998 and require
engine oils meeting their own specs and/or top-of-the-line CH-4 oils, as noted below.
For instance, Cummins’ ’99 N14 Plus recommendation for “normal duty” (70,000-80,000 pounds GVW/5.5 to 6.5 mpg) is 20,000 miles with
CG-4 oils, 30,000 miles with CH-4 oils meeting Cummins CES 20071 spec and 35,000 miles meeting Cummins CES 20076 spec. An LF 9009 oil
filter is also required.
For its ’98 N14 Plus engines, the comparable mileages were 22,500 with CG-4, 35,000 miles with CH-4 and 45,000 miles with CES 20076. For
vocational versions of the same engine, the reduction in drain interval between ’99 and ’98 engines is 20%.
Mack is sticking with its 40,000-mile oil drain recommendation for 1999 but only with the following qualifications: use of Mack EO-M spec oil
(which exceeds CH-4 qualifications), sustained high-mileage operation over 100,000 miles annually averaging 6 mpg or better. Engines must be E7 with
V-Mac II or the new E-Tech engine. Engines must be equipped with Mack’s Centru-Max filter with OEM centrifugal rotor.
Detroit Diesel’s recommendations are tied closely to the use of oil analysis regularly for drains above 15,000 miles, a minimum of 6.5 mpg and less
than 40% idling time. Oil must be CH-4 or better.
Conclusions: If you’re buying ’99 big-bore diesel engines, pay close attention to the manufacturers’ recommendations. With all the interest and hype
about extended drain intervals in the past few years, 1999 models have very different recommendations and very specific oil and filtration requirements.
Take heed!
  Reply With Quote
Old November 23rd, 1999, 09:09   #8
Veteran Member
Join Date: Nov 1999
Location: Dixie


It seems the best way to test your theory is to do "trendlined" oil analysis, ie: take a sample every 5k miles and look at wear rates. I think you'll find (at least with the amsoil formulations) that whether you change every 5k/10k/15k has little or NO effect on wear rates. The reason for this is clearly stated in your initial post. Most soot particles are below 1 micron in size - even the amsoil by-pass filter removes less than 40% of these (I have some field test data on over-the-road trucks). This is smaller than the clearances between moving parts (bearings, piston rings and cylinder walls, valve train components), so these particles don't contribute to wear until they agglomerate (sic) and can no longer be suspended.

If you'd like to run this test using one of the Amsoil diesel oils, I'd suggest the 15w-40 diesel & marine - it has their most robust additive package (approx. 700 ppm of magnesium; 5000 ppm of calcium;1300 ppm phosphorus; 1500 ppm zinc). This oil is formulated for extended drains in turbocharged marine diesel engines; running high sulphur fuel in a corrosive environment (overkill for a TDI engine). I'll pay for the oil analysis testing! Please give me a call at home if you're interested - you've got my number.

(this offer is only good for Skypup - Ric, you're gonna have to go it alone)

TwoSlick is offline   Reply With Quote
Old November 23rd, 1999, 09:20   #9

Geez, that is a generous offer for sure. I will give you a call and we can discuss it. Thanks a bunch for being such a great resoruce!
  Reply With Quote
Old November 23rd, 1999, 10:36   #10
Dominique Cormann
Veteran Member
Join Date: Oct 1999
Location: Guelph, Ontario Canada


Polishs the upper cylinder walls???

Oh boy. Sorry but the whole reason why you have hash marks in an engine there is so that oil can cling to the marks.

When they wear away, you increase wear in that area because the oil doesn't cling as well.

Also consumption GOES WAY UP! Since the oil can't cling to the cylinder walls and slides up past the rings.

You are right though, small particles do create wear, yes they do 'polish' things, however its NOT good that they do this.

If you want to see pictures of this go here.

Ric, no offense intended, but where do you come up with these thoughts?

My Project GTD and diesel page

Dominique Cormann is offline   Reply With Quote
Old November 23rd, 1999, 10:42   #11
Ric Woodruff
BANNED, Ric went to Coventry.
Join Date: Feb 1999

Who is the author, SkyPup?
Ric Woodruff is offline   Reply With Quote
Old November 23rd, 1999, 10:50   #12

Excellent posts, Dominique. As you know the TDI engine has had the top piston ring moved up 6mm towards the pistons crown, thereby increasing the oil exposure to the conbustion chamber heat and soot formation. When this critical area becomes exposed to soot loaded oil, it suffers extreme wear. However, even worse than this is the lack of heat transfer from the aluminum forged pistons to the cylinder walls due to all the soot damage. The piston temperature rises outasight since it has lost it's main heat transfer outlet. Also, the tiny tiny piston bottom oil lubricating jets function less and less as they are blocked with soot contamination, thereby robbing the piston of its only other source of heat removal. Ultimately, severe wear and failure ensue.
Ric's TDI engine is already doomed, there is simply no hope for it or him in the future.
  Reply With Quote
Old November 23rd, 1999, 10:51   #13
TDIClub Enthusiast
Pre-Forum Veteran Member
Lug_Nut's Avatar
Join Date: Jun 1998
Location: Sterling, Massachusetts. USA

The 40% removal rate for sub-micron particulate is per pass through the media. The second time through about 40% of the missed 60% (24% of the original total) will be removed. The third time through 40% of the remaining (about 10% of the original amount) will be taken out. Within three passes 74% of the sub-micron particles will be removed. They will never be completely filtered out as new soot is being added during engine operation, but the level will be reduced to a point significantly less than the absolute filtration level.
Lug_Nut is offline   Reply With Quote
Old November 23rd, 1999, 10:52   #14

Ric has never been able to grasp the idea that "polishing" metal with abrasive particles involved removing a certain amount of the metal. "Polishing" is not a good thing. Unfortunately, it happens in all engines. (Otherwise they'd last forever.) If soot increases the "polishing", it also increases wear. It's a simple rule.

It's been my observation (based on actual analysis of used oil) that the viscosity of a CG-4 rated synthetic begins to increase once you reach about 0.8% soot content. That happens to occur at around 10,000 miles. (What a coincidence, eh?) I'd consider that to be a "maxiumum" allowable soot content. As I recall, Johnathan Bartlett reached about 0.8% after 50,000 miles using a good bypass filter kit.

3% is WAY too much, Ric! You can expect to see a major increase in viscosity by that time. (As in double, or triple!)

  Reply With Quote
Old November 23rd, 1999, 11:46   #15
Veteran Member
Join Date: Aug 1999
Location: Pasco, Florida, USA
Fuel Economy: 54/50/46


I get queasy every time I hear the word "polishing" relating to the interior of my TDI engine.

Lets see... tiny soot particles polish bores and main bearings.. Royal Purple's website extolls the virtues of their oil by making statements about "micro-polishing" occuring inside engines using Long Rider oil.

What gives?

I'm sure I could "micro-polish" all bearing surfaces inside my engine "better" than either soot or Long Rider by adding some fine Jeweler's Rouge to my crankcase. How about lapping compound?

The only thing I want in my TDI's crankcase is oil I put there, period.

For those bent on additional filtration, wouldn't it be more productive/cheaper to just figure out a way to:

Using a siphon tube to remove the crankcase oil, say, every 5,000 to 8,000 miles.

Filter it outside the crankcase using a hand-cranked perstatltic pump (cheap model airplane hobby-store item) and appropriate filter medium (fine sub-micron water-polishing filters).

Replace oil into crankcase + some inevitable makeup oil.

An hour's work (maybe less) every so often and mucho longer drain intervals, (of course) ONLY as borne out by oil analysis.

If that's too much trouble, just drain the stuff. Am I the only one not spoiled here? 10,000 miles seems eminently acceptable even when using/paying for Amsoil 3000. I wish my low-tech diesel Volvo 240 had that drain interval.

Get real... Anything but oil in the crankcase is going to reduce longevity.

Why continue fighting over what constitutes "Acceptable levels" instead of just asking VW Germany what is considered acceptable by the designers?

I've learned quite a bit from the many oil threads, but sometimes recurring themes like this "polishing" stuff make me ill.


99.5 Jetta TDI GL Silver/Beige
ANTARTI is offline   Reply With Quote

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

All times are GMT -7. The time now is 00:17.

Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Copyright - TDIClub Online LTD - 2017
Contact Us | Privacy Statement | Forum Rules | Disclaimer
TDIClub Online Ltd (TDIClub.com) is not affiliated with the VWoA or VWAG and is supported by contributions from viewers like you.
© 1996 - 2017, All Rights Reserved
Page generated in 0.17625 seconds with 9 queries
[Output: 127.75 Kb. compressed to 108.37 Kb. by saving 19.38 Kb. (15.17%)]