Final Horrifyingly Stupid Question - OCI?

CoryS

Veteran Member
Joined
Dec 28, 2005
Location
PA
TDI
2017 Jetta 1.4T
I've had my car for a little while now and I drive A LOT. I'm probably at about 1,000,000 miles in the past 20 years and have done all of my own oil changes at 3,000 or 5,000 mile intervals. Seems like most are comfortable with 10,000 miles and that's prolly a "correct" OCI.
I'm pretty "one with the oil" (from my experiences) and do feel a slight "roughening" of the engine right before 7,500 miles. So, I've settled on a 7,500 mile OCI and am pretty comfortable with that. The engine runs noticably better after the oil/filter change (at 7,500 miles). Not night and day, but enough to suggest that 7,500 is a good move. Possibly overkill, but I'd rather that than underkill. I have a customer that has 45,000 miles of the same oil in his BMW. I cringed violently and spit out some teeth.
 

Sip'n Diesel

Veteran Newbie
Joined
Apr 13, 2008
Location
San Joaquin Valley, I have VCDS (KII-USB)
TDI
2003 ALH: 254,000 miles
CoryS said:
I've had my car for a little while now and I drive A LOT. I'm probably at about 1,000,000 miles in the past 20 years and have done all of my own oil changes at 3,000 or 5,000 mile intervals. Seems like most are comfortable with 10,000 miles and that's prolly a "correct" OCI.
I'm pretty "one with the oil" (from my experiences) and do feel a slight "roughening" of the engine right before 7,500 miles. So, I've settled on a 7,500 mile OCI and am pretty comfortable with that. The engine runs noticably better after the oil/filter change (at 7,500 miles). Not night and day, but enough to suggest that 7,500 is a good move. Possibly overkill, but I'd rather that than underkill. I have a customer that has 45,000 miles of the same oil in his BMW. I cringed violently and spit out some teeth.
:confused:UOA?!?!:D
 

whitedog

Veteran Member
Joined
Jul 12, 2004
Location
Bend, Oregon
TDI
2004 Jetta that I fill by myself
CoryS said:
I have a customer that has 45,000 miles of the same oil in his BMW. I cringed violently and spit out some teeth.
Apparently Deere is starting to push bypass filters on engines running EGR and there has been some incredible results. There is a wheel loader with over 100,000 hours on 2,000 hour OCIs.

Standard conversion is 45 Miles to the Hour.

I'm sure that oil sampling is done, but I am cautious about the additives running that many hours.

Anyway, just something interesting I heard today.
 

Birdman

Top Post Dawg
Joined
Apr 7, 1999
Location
Near Hagerstown MD.
TDI
Jetta 2001 Died by Truck one snowy day. Jetta 2003
I first started running synth oil way back in 1979 in my 78 Rabbit diesel. I was till then a 3000 miles for oil changes but that car with its added turbo went 220 before I sold it on 10000 miles changes and all my cars since then have had the same treatment including my 85 gasser that had 260 on it with the pan or head never being pulled car got on Avg. 35 MPG with the higher 5th gear I put in it. So I am sold on 10,000 mile changes. you will find people running 20,000 and not just taking samples and the oil still is good. The only problem VW has had that I have seen is people using the wrong oil.
 

bikeprof

Veteran Member
Joined
Sep 2, 2005
Location
Pagosa Springs, Colorado(YEAH!)
TDI
1996 Passat B4 Variant white, 1996 Town & Country 3.8 LXI
stefan_b said:
We switched to USLD quite a few years ago - still, where I live (Romania) we are not allowed to use flex service intervals due to dust content.

I believe that dust will affect the oil quite a bit, so we are still classifying all engines as going through "severe" conditions and changing the oil at least 2x as often as say Germany. This can easily be seen by comparing air filters - in Germany an air filter is good for 90.000Km (60.000 Mi) while we change them every 15-30.000Km. This is another factor to consider when determining OCI.
Nice, Stefan...
I aggree with you that OCI's are something that needs to be done on a basis of need. The harder the motor works, the more dust in the air(ie. deserts), or more stop and go traffic than normal, then the motor should be given a fresh dose of 1. oil 2. oil filter.

I live in the mountains, in the up-down of elevation and have to cross high plains where dirt IS in the air, even getting to my house from town, there is dirt/dust!
3-5k for the filter, 10 to 15k for the oil(will get an OCI soon from the "new" engine to verify its condition...).
 

barshnik

Veteran Member
Joined
Jul 14, 2008
Location
Las Vegas, NV
TDI
2013 Passat SE w/roof, nav
I've only got 11k miles on the '09 JSW TDI, but already have an oil change plan. I did an oil analysis at 4k, changed oil at 4.5k when the OA showed a lot of 'wear metals'. Did another UOA at 10k plus a oil change, wear metals are going down a little. Looks like the engine will be somewhat 'broken in' by 15k, will do another change then. After that, if analysis shows lower Aluminum, Iron, Copper, etc. I'll go to 7500 mile oil changes, maybe 10k over the 'winter' here in LV.

My UOA results are in the UOA thread in this section. I'll trust what the lab guys say rather than the 'by the book' 10k that VOA says. I live in an extremely hot, dirty part of the world, and I'm not sold on 'one size fits all' for oil changes. Hey, maybe it'll turn out that I can run 12k or 15k between changes - we'll see. For the near future, though, it'll be oil analysis every 5k miles though and go by those results.

John F
LV NV
 

TornadoRed

Top Post Dawg
Joined
Aug 3, 2003
Location
Saint Paul (ex-San Diego)
TDI
2003 Golf GL 5-spd, red; 2003 Golf GLS 5-spd, indigo blue; 2003 Jetta TDI wagon, Candy White
barshnik said:
I've only got 11k miles on the '09 JSW TDI, but already have an oil change plan. I did an oil analysis at 4k, changed oil at 4.5k when the OA showed a lot of 'wear metals'. Did another UOA at 10k plus a oil change, wear metals are going down a little. Looks like the engine will be somewhat 'broken in' by 15k, will do another change then. After that, if analysis shows lower Aluminum, Iron, Copper, etc. I'll go to 7500 mile oil changes, maybe 10k over the 'winter' here in LV.
My UOA results are in the UOA thread in this section. I'll trust what the lab guys say rather than the 'by the book' 10k that VOA says. I live in an extremely hot, dirty part of the world, and I'm not sold on 'one size fits all' for oil changes. Hey, maybe it'll turn out that I can run 12k or 15k between changes - we'll see. For the near future, though, it'll be oil analysis every 5k miles though and go by those results.
John F
LV NV
I question your interpretation of the data. IMO you've been draining perfectly good oil, so I wonder if you have another vehicle you can pour this used oil into?

A few ppm of wear metals in oil do not prevent the oil from serving its purpose of protecting against additional wear. Your test results do not show TBN, nitration or oxidation -- all you've got is viscosity and solubles, but these don't show anything of concern.

UOA is properly used to detect trends. The testing you've done on your new engine does not show any worrisome trends.

IMO there is little to be gained by performing such extensive testing of a new engine. If I was breaking in a new engine, I would probably wait until 20k miles before doing even a baseline test, then maybe again at 40k or 50k.
 

TooSlick

Top Post Dawg
Joined
Dec 2, 1999
Location
Dixie
TDI
Audi 100S
The primary reason for changing the oil in a TDI at < 10,000 miles is if you are running high soot levels. If you plot Fe/Cr as a function of soot percentage, you'll see that once you exceed a soot percentage of approx 0.5%, the relationship between soot & iron/chrome wear is basically linear. What that means in laymans terms is that if you double the soot concentration, you double the ring/cylinder & valvetrain wear.
If you are running a low viscosity, VW Spec oil (even the 5w-40/VW 505.01 oils are thin for a turbo-diesel), I'd change oil when the soot level is > 0.5% - regardless of how many miles are on the sample. If you're doing 5k-6k oil changes, it's not absolutely necessary to change the oil filter every time, I'd change those every 10k-12k miles....
 

MotoWPK

Veteran Member
Joined
Feb 23, 2009
Location
Colorado
TDI
2009 Jetta
You have to expect the experts who specify the oil change interval and back up that specification with a warranty (though one that doesn't last nearly as long as you probably expect to keep the vehicle) would have the knowledge and confidence to back up their recommendation.
That said, I betrayed this logic by reverting to old habits and had the dealer change the oil today at ~5200 miles while my '09 TDI was in to diagnose an engine check light event.

Tom
 

TornadoRed

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Joined
Aug 3, 2003
Location
Saint Paul (ex-San Diego)
TDI
2003 Golf GL 5-spd, red; 2003 Golf GLS 5-spd, indigo blue; 2003 Jetta TDI wagon, Candy White
MotoWPK said:
I betrayed this logic by reverting to old habits and had the dealer change the oil today at ~5200 miles while my '09 TDI was in to diagnose an engine check light event.
It was free, right? And the dealership used the correct oil, right?

And they didn't screw up anything else while you were there, right?
 

TedM

New member
Joined
May 1, 2009
Location
Newport Beach, CA
TDI
2009 Jetta Sportwagon
My new JSW has only 200 miles on it so far (My God what an incredible car!). I've gotten very important info from the forums regarding break-in (don't baby it) and the OCI (follow the manual, relax and drive) which I will endeavor to follow later on.

However, it seems to me that during the earliest stages of break-in (say, up to about 1000 miles (1600km)), it might be wise to change only the filter, top up to the proper level, then leave it alone for the rest of the full 10,000 mile OCI.

I've seen comments such as the one by TornadoRed saying this is basically useless, and I would agree if we were talking about higher mileage. But would a filter-only change be a good idea in just this one instance - after the first 1000 (or 500 - or 250 - or 100) miles?

I've gotten varied advice about this over the years, including one fellow (a professional mechanic) who said the best procedure was to change the filter IMMEDIATELY after getting a new car home from the dealership. Comments?
 

jayb79

Top Post Dawg
Joined
May 20, 2000
Location
Exeter,NH
I have been doing 20k mile oil change in my NB since 100k (10k b4 that).
It is coming up to its next change at 360k. Now is useing about 2 qts.over the 20k interval.
 

shawnfb

Member
Joined
Apr 24, 2010
Location
Florida
TDI
sportwagon 2010
what about adding to the existing....

Drivbiwire said:
STOP STOP STOP!
The ORIGINAL factory APPROVED oil change interval is 30,000 miles! YES 30,000 MILES!!
Did you comprehend that?
THE ORGINAL OIL CHANGE INTERVAL APPROVAL IS 30,000 MILES!!!
Now that I have that off my chest,
VW reduced the interval from 30,000 miles to 10,000 miles in the US market...any guesses why?
Because people like you either:
1) Can't read the owners manual
2) Don't trust the car makers
3) Can't follow directions
4) Fail to adhere to the service indicator in the car
VW does NOT want oil change intervals of less than 10,000 miles due to how the oils function in the engine, shorter intervals INCREASE WEAR, Don't argue with me about it, if you take the time to track wear rates during an oil change at 250 mile intervals you can plot the reduction and stabilization of the wear rates out beyond 25,000 miles!
Think of oil as having 2 types of wear reducing additives, the first provides protection by/thru detergancy (cleansing of internal surfaces), dispersing soot, neutralizing acids (not an issue now with ULSD), and several other types as well. These additives are generally very specific to diesel engines and must pass specific tests in VW Diesel engines.
The next type of additive is a wear additive. These protect the engine where the thickness of oil may be too thin to prevent metal to metal contact. Other additves in this type range also provide protection to the cam and lifters, engine bearings, piston wrist pins etc.
Now pay attention, the 2nd group of additives account for less than 3% of the total volume of the oil. These additives also account for 90% of the engines oil protection! These additives require heat and pressure to bond with the critical wear surfaces, but due to the low percentage of additive in the oil they require time to fully place on those surfaces by the pressures of the component they are protecting. Example, an engine at operating temperature at the point where the cam presses on the lifter generates in excess of 90,000 psi, that pressure and the heat of the engine causes the 3% portion of the 1 micron thick oil film to form a crust or sacrifical layer at the point of contact. Since only 3% of the oil contains the wear additives, it requires hundreds of thousands of passes to generate a sufficient film to stop the wear at this specific point in the engine.
Everybody is quick to make the arguement that the old oil had these additives so they are already in place, right? not quite!
Remember the first type of additive? In that 1st group you had "detergents" that cleanse the inside of the motor. These cleansers are used up very rapidly after an oil change since they attack the remaining oil that was left after the oil change. These cleansers if you will also reduce the effectiveness of the high pressure wear additives...See where this is going?
Before explaining further, after that initial period the dispersants in the oil work to prevent the adhering of the particles in the oil to any of the internal surfaces. These additives are often unique to diesel engines are also the reason why the oil looks so black so quickly, they are doing their job by preventing the soot from building up in any one place instead they are dispersed in the oil evenly throughout the oil sump which prevents sludging and other contamination related issues.
Back to the detergents and the high pressure additives, the layers of high pressure additives leftover are not being replenished after the oil change due to the cleaning process that is going on with the new oil to neutralize the remaining acids, and other contaminants in the engine. As the cleaners in the oil are used up in the first 500-1000 miles, the wear additives are able to re-generate a protective layer in the engine that stops the wear at that location.
You break down the oils life cycle like this:
Phase 1: Detergants attack the internals removing accumlated contaminants, neutralize acids and force those into suspenstion in the oil. This period of time lasts between 500-1000 miles
Phase 2: During the first 1000 miles the oils viscosity provides the majority of the wear protection by virtue of the film it creates on the surfaces. This phase generates relatively high wear rates but due to the short duration this is accepted due to the removal of contaminants that could result in long term damage to the motor. Wear rates in the period of time are generally speaking 5-10ppm per 1000 miles.
Phase 3: Detergents are now used up and the oil additives are forming their protective layers in the "extreme pressure" regions of the motor. Now the oil additives are working in conjunction with the oil film and the wear rates drop from 10ppm per 1000 miles to around 1-2ppm per 1000 miles.
Phase 4: Longterm peace! The oil is operating in a period of equilibrium, the wear additives are placed, Oil viscosity is in perfect range for the engine, Dispersants are continually working to prevent soot and other contaminants from accumulating on the surfaces and wear rates remain between 1-3ppm per 1000 miles.
Phase 5: Oil run out, the oil during this phase begins to increase in viscosity (or thin in some cases), Extreme pressure additives begin to lose effectiveness due to increased concentrations of wear particles (VW tests out to 8%, most oil changes never see in excess of 2% after 30,000 miles). This is when you begin to see a rise in the wear metal formation in the engine. Often wear metals during this phase rise to the 3-8ppm per 1000 mile range. Notice that the wear metals being generated are still LOWER than they were in the first 1000 miles?
--------------------------------------------------------------
When somebody says they are going to change the oil every 5000 miles or twice as often they are DOUBLING the number of detergent cycles and DOUBLING the number of cycles where the engine is running at it's highest wear rates!
PPM/Fe (generation of Fe in 1000 mile increments)
Short drain intervals
1K oil change
10ppm = 10ppm in 1000 miles = 10ppm/1000 miles
3K oil change
10+2+2 = 14ppm in 3000 miles = 4.6ppm/1000 miles
5K oil change
10+2+2+2+2: Change oil = 18ppm in 5000 miles = 3.6ppm/1000 miles
Long drain intervals
10K oil change
10+2+2+2+2+2+2+2+2+3 = 29 ppm in 10,000 miles = 2.9ppm/1000 miles
15K oil change
10+2+2+2+2+2+2+2+2+3+3+3+3+3+3 = 44ppm in 15,000 miles = 2.9 ppm/1000 miles
20K oil change
10+2+2+2+2+2+2+2+2+3+3+3+3+3+3+3+3+3+4+4 = 61ppm in 20,000 miles = 3.3ppm/1000 miles
When ppm of Fe per 1000 miles reaches 5-7ppm per 1000 miles you can consider the oil ready for a change...
The above is based on real world TDI oil samples.
I have personally used up to 25,000 mile oil drain intervals on my TDI and still never reached the 5-7ppm range! I changed it at that time due to soot and TBN depletion (high sulfur fuel at the time).
Anybody that tells you that short oil drain intervals are good for your motor don't know what they are talking about!
DB
what about adding to the existing oil when the oil level is going down on the dipstick?..
 

40X40

Experienced
Joined
Feb 12, 2006
Location
Kansas City area, MO
TDI
2013 Passat SEL Premium
shawnfb said:
what about adding to the existing oil when the oil level is going down on the dipstick?..


I am all for it. Do you have a question or are you just playing with the quote function? Your manual tells you specifically which oil to use and how to check the oil level. :eek:

Bill
 

SonyAD

banned Borat
Joined
Nov 15, 2009
Location
București, România
TDI
Peugeot 206 2.0 HDi
What about engines with rollerised valvetrains?

If the dispersant package is incompatibile with the EP and AW additives wouldn't they be captive from the moment they were added to the oil?
 

40X40

Experienced
Joined
Feb 12, 2006
Location
Kansas City area, MO
TDI
2013 Passat SEL Premium
TedM said:
My new JSW has only 200 miles on it so far (My God what an incredible car!). I've gotten very important info from the forums regarding break-in (don't baby it) and the OCI (follow the manual, relax and drive) which I will endeavor to follow later on.

However, it seems to me that during the earliest stages of break-in (say, up to about 1000 miles (1600km)), it might be wise to change only the filter, top up to the proper level, then leave it alone for the rest of the full 10,000 mile OCI.

I've seen comments such as the one by TornadoRed saying this is basically useless, and I would agree if we were talking about higher mileage. But would a filter-only change be a good idea in just this one instance - after the first 1000 (or 500 - or 250 - or 100) miles?

I've gotten varied advice about this over the years, including one fellow (a professional mechanic) who said the best procedure was to change the filter IMMEDIATELY after getting a new car home from the dealership. Comments?

Just read and follow the directions in the owners manual. (first oil and filter change is at 10,000 miles, right?)

Bill
 

ccroader

Member
Joined
Apr 6, 2011
Location
Arlington, VA
TDI
2011 Touareg TDI
Someone over on clubtouareg seems to think that going to 10K with the factory fill is not a good idea due to the vehicle's heavier load on the engine. He did an oil analysis that claims to show degradation of the oil at 5K miles. I have no idea if there's any merit to that or not. I tend to believe the factory, and the logic presented in this thread, but am wondering if there might be any difference in recommendation with the Touareg's 3.0.
 

tdiatlast

Top Post Dawg
Joined
Jan 21, 2009
Location
Fort Worth, Texas
TDI
2009 Sportwagen (boughtback); 2014 Passat TDI SEL (boughtback)
I can't cite the thread, but I believe another has posted a similar UOA for the 3.0.
 

tdi90hp

Veteran Member
Joined
Feb 5, 2002
Location
Canuckland
TDI
2011 Golf TDI 6 speed(gone but NEVER forgotten)
why is this a mystery? have you ever heard of a TDI engine blowing up cause of poor oil, dirty oil. unchanged oil?? nope
but you have read hundreds and hundreds of posts of people following the VW spec and getting 300k-400K etc...
why are you worried?
just go with VAG. they know the cars...they sell them all over the world....10K is conservative like DBW has stated over and over. go with that....my 2c worth.
 

ccroader

Member
Joined
Apr 6, 2011
Location
Arlington, VA
TDI
2011 Touareg TDI
Like I said, I'm not worried. I'm following the factory rec, and believe the arguments presented by drivebywire. It's just that the guy who believes you should change at 5K says this thread only applies to the smaller engines/vehicles. I don't believe that's the case, and am just looking for some additional clarification.
 

tdiatlast

Top Post Dawg
Joined
Jan 21, 2009
Location
Fort Worth, Texas
TDI
2009 Sportwagen (boughtback); 2014 Passat TDI SEL (boughtback)
why is this a mystery? have you ever heard of a TDI engine blowing up cause of poor oil, dirty oil. unchanged oil?? nope
but you have read hundreds and hundreds of posts of people following the VW spec and getting 300k-400K etc...
why are you worried?
just go with VAG. they know the cars...they sell them all over the world....10K is conservative like DBW has stated over and over. go with that....my 2c worth.
Have you never read anything about PD camshafts and VW approved oils?

CCroader, should you be worried? Not necessarily. The 3.0 is a different engine. You are doing the right thing by asking this question. I know there was a UOA posted here from a 3.0 Tuareg, that showed the 10k mile OCI was optimistic...I just can't find the thread.

A little help, someone?
 

TornadoRed

Top Post Dawg
Joined
Aug 3, 2003
Location
Saint Paul (ex-San Diego)
TDI
2003 Golf GL 5-spd, red; 2003 Golf GLS 5-spd, indigo blue; 2003 Jetta TDI wagon, Candy White
Have you never read anything about PD camshafts and VW approved oils?
Those who bought PD TDIs, and were unlucky enough to get one with a cam from the bad batch(es), learned that it didn't really matter whether they used a VAG 505.01-rated oil or not.
 

tdi90hp

Veteran Member
Joined
Feb 5, 2002
Location
Canuckland
TDI
2011 Golf TDI 6 speed(gone but NEVER forgotten)
Those who bought PD TDIs, and were unlucky enough to get one with a cam from the bad batch(es), learned that it didn't really matter whether they used a VAG 505.01-rated oil or not.
thank you ! you beat me to the reply. The cam was a problem and had little or zero to do oil change interval....
 

tdiatlast

Top Post Dawg
Joined
Jan 21, 2009
Location
Fort Worth, Texas
TDI
2009 Sportwagen (boughtback); 2014 Passat TDI SEL (boughtback)
Thanks for the correction. I misunderstood the camshaft issue...thought it was a combination of incorrect oil AND defective camshafts. tdi90hp...sorry for the smart-a$$ post!

I still think that the 3.0 OCI is different, based on a posted UOA, than the 2.0...unless I misunderstood that as well!
 
Last edited:

tdi90hp

Veteran Member
Joined
Feb 5, 2002
Location
Canuckland
TDI
2011 Golf TDI 6 speed(gone but NEVER forgotten)
Thanks for the correction. I misunderstood the camshaft issue...thought it was a combination of incorrect oil AND defective camshafts. tdi90hp...sorry for the smart-a$$ post!

I still think that the 3.0 OCI is different, based on a posted UOA, than the 2.0...unless I misunderstood that as well!

no worries...god knows I make enough smart ass remarks....keep well and keep that engine oil changed every 10k
 

stormy

Active member
Joined
Jul 21, 2012
Location
Germany
TDI
Seat Leon 5F ST DSG 2.0TDI EA288
STOP STOP STOP!

The ORIGINAL factory APPROVED oil change interval is 30,000 miles! YES 30,000 MILES!!

Did you comprehend that?

THE ORGINAL OIL CHANGE INTERVAL APPROVAL IS 30,000 MILES!!!

Now that I have that off my chest,

VW reduced the interval from 30,000 miles to 10,000 miles in the US market...any guesses why?

Because people like you either:
1) Can't read the owners manual
2) Don't trust the car makers
3) Can't follow directions
4) Fail to adhere to the service indicator in the car

VW does NOT want oil change intervals of less than 10,000 miles due to how the oils function in the engine, shorter intervals INCREASE WEAR, Don't argue with me about it, if you take the time to track wear rates during an oil change at 250 mile intervals you can plot the reduction and stabilization of the wear rates out beyond 25,000 miles!

Think of oil as having 2 types of wear reducing additives, the first provides protection by/thru detergancy (cleansing of internal surfaces), dispersing soot, neutralizing acids (not an issue now with ULSD), and several other types as well. These additives are generally very specific to diesel engines and must pass specific tests in VW Diesel engines.

The next type of additive is a wear additive. These protect the engine where the thickness of oil may be too thin to prevent metal to metal contact. Other additves in this type range also provide protection to the cam and lifters, engine bearings, piston wrist pins etc.

Now pay attention, the 2nd group of additives account for less than 3% of the total volume of the oil. These additives also account for 90% of the engines oil protection! These additives require heat and pressure to bond with the critical wear surfaces, but due to the low percentage of additive in the oil they require time to fully place on those surfaces by the pressures of the component they are protecting. Example, an engine at operating temperature at the point where the cam presses on the lifter generates in excess of 90,000 psi, that pressure and the heat of the engine causes the 3% portion of the 1 micron thick oil film to form a crust or sacrifical layer at the point of contact. Since only 3% of the oil contains the wear additives, it requires hundreds of thousands of passes to generate a sufficient film to stop the wear at this specific point in the engine.

Everybody is quick to make the arguement that the old oil had these additives so they are already in place, right? not quite!

Remember the first type of additive? In that 1st group you had "detergents" that cleanse the inside of the motor. These cleansers are used up very rapidly after an oil change since they attack the remaining oil that was left after the oil change. These cleansers if you will also reduce the effectiveness of the high pressure wear additives...See where this is going?

Before explaining further, after that initial period the dispersants in the oil work to prevent the adhering of the particles in the oil to any of the internal surfaces. These additives are often unique to diesel engines are also the reason why the oil looks so black so quickly, they are doing their job by preventing the soot from building up in any one place instead they are dispersed in the oil evenly throughout the oil sump which prevents sludging and other contamination related issues.

Back to the detergents and the high pressure additives, the layers of high pressure additives leftover are not being replenished after the oil change due to the cleaning process that is going on with the new oil to neutralize the remaining acids, and other contaminants in the engine. As the cleaners in the oil are used up in the first 500-1000 miles, the wear additives are able to re-generate a protective layer in the engine that stops the wear at that location.

You break down the oils life cycle like this:

Phase 1: Detergants attack the internals removing accumlated contaminants, neutralize acids and force those into suspenstion in the oil. This period of time lasts between 500-1000 miles

Phase 2: During the first 1000 miles the oils viscosity provides the majority of the wear protection by virtue of the film it creates on the surfaces. This phase generates relatively high wear rates but due to the short duration this is accepted due to the removal of contaminants that could result in long term damage to the motor. Wear rates in the period of time are generally speaking 5-10ppm per 1000 miles.

Phase 3: Detergents are now used up and the oil additives are forming their protective layers in the "extreme pressure" regions of the motor. Now the oil additives are working in conjunction with the oil film and the wear rates drop from 10ppm per 1000 miles to around 1-2ppm per 1000 miles.

Phase 4: Longterm peace! The oil is operating in a period of equilibrium, the wear additives are placed, Oil viscosity is in perfect range for the engine, Dispersants are continually working to prevent soot and other contaminants from accumulating on the surfaces and wear rates remain between 1-3ppm per 1000 miles.

Phase 5: Oil run out, the oil during this phase begins to increase in viscosity (or thin in some cases), Extreme pressure additives begin to lose effectiveness due to increased concentrations of wear particles (VW tests out to 8%, most oil changes never see in excess of 2% after 30,000 miles). This is when you begin to see a rise in the wear metal formation in the engine. Often wear metals during this phase rise to the 3-8ppm per 1000 mile range. Notice that the wear metals being generated are still LOWER than they were in the first 1000 miles?

--------------------------------------------------------------

When somebody says they are going to change the oil every 5000 miles or twice as often they are DOUBLING the number of detergent cycles and DOUBLING the number of cycles where the engine is running at it's highest wear rates!

PPM/Fe (generation of Fe in 1000 mile increments)
Short drain intervals
1K oil change
10ppm = 10ppm in 1000 miles = 10ppm/1000 miles

3K oil change
10+2+2 = 14ppm in 3000 miles = 4.6ppm/1000 miles

5K oil change
10+2+2+2+2: Change oil = 18ppm in 5000 miles = 3.6ppm/1000 miles

Long drain intervals
10K oil change
10+2+2+2+2+2+2+2+2+3 = 29 ppm in 10,000 miles = 2.9ppm/1000 miles

15K oil change
10+2+2+2+2+2+2+2+2+3+3+3+3+3+3 = 44ppm in 15,000 miles = 2.9 ppm/1000 miles

20K oil change
10+2+2+2+2+2+2+2+2+3+3+3+3+3+3+3+3+3+4+4 = 61ppm in 20,000 miles = 3.3ppm/1000 miles

When ppm of Fe per 1000 miles reaches 5-7ppm per 1000 miles you can consider the oil ready for a change...

The above is based on real world TDI oil samples.

I have personally used up to 25,000 mile oil drain intervals on my TDI and still never reached the 5-7ppm range! I changed it at that time due to soot and TBN depletion (high sulfur fuel at the time).

Anybody that tells you that short oil drain intervals are good for your motor don't know what they are talking about!

DB

DB, thank you very much for this information!

I just bought a 2010 GTD and had them do a oilchange before I picked it up. I was going to change it again after 6250 miles (10t km) and then take it to the 60tkm inspection. After reading this I will leave the oil where it is until the inspection is do. That would be 12500 miles (20tkm) on the oil then:)

I didnt want to leave the oil in there for 20tkm, the plan is to do the 30tkm inspection and change the oil extra half way. Which would be about 10kmiles per oil change, I still plan on sticking to this.

Any new information on how the TBN holds up in the CR-TDI´s?
http://www.oil-analysis.org/tan_tbn_test.html
 

naturist

Veteran Member
Joined
Apr 2, 2001
Location
Bro Jerry's hometown, Virginia
TDI
2001 Jetta TDI, 2005 Jeep Libby CRD, 2012 BMW X5 35d
Simple solution, @OP: set your OCD to this mantra: Owner's Manual, Owner's Manual, Owner's Manual, . . . ."

VW has entire teams of well educated, carefully trained, and highly compensated detail obsessive engineers, who've been guided by teams of equally highly compensated lawsuit-adverse lawyers into specifying OCIs that are extremely conservative in their estimates of best practices. What they've come up with is a safe-enough-nobody-could-ever-be-damaged OCI to be stated in that Owner's Manual.

Second-guessing them by any less a team, especially without ruining several million dollars worth of engines in the necessary research, is outright stupid.

So start chanting it now: Owner's Manual, Owner's Manual, Owner's Manual, . . . .
 
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