Frequent oil changes bad for PD???? check this out....

[Buller_Scott]

hey guys, in my current state of unemployment, i was wasting time cruising the net, when i stumbled across a thread in tdi club. i've lifted some pretty meaty information regarding too-frequent oil changes, and pumpe duse engines:

Shame on the prior owner for changing at 5k miles interval. Since you are not experiencing any problems, follow the recommended oil change interval for your car.



Originally Posted by Blue02JettaTDI
I do 5-6k oil changes. Theyre cheap and easy to do.
Originally Posted by NB_TDI
Way to fail.




Quote:
Originally Posted by Blue02JettaTDI
I do 5-6k oil changes. Theyre cheap and easy to do.

Originally Posted by Drivbiwire
And three times the wear rates on a car that cannot afford them.

The owners whos PD's I tend to, are trying to recover the money they put into the car as a result of incorrect oil usage. Now that the motors are running properly and wear has been eliminated as a future issue we are doing what we can to reduce the wear and maximize the life of the engines.

They like the fact that they can safely run 15,000 plus miles between changes and have wear rates that are so low that even they see a need to go to 20K. Of course this is backed up by an occasional oil sample (not every time) but typically every 3rd to 4th oil change. This only serves to validate our oil change intervals.

Running a PD motor in a perpetial state of detergency has got to be the worst thing you can do to these motors. You want to allow the dispersants to do the job of keeping an engine clean and not continually flush it with detergants. Ever look at the hands of somebody with OCD, not pretty now imagine what is going on in your motor. By changing every 5K the additives have just started to stabilize and now you dump the oil and spike the detergants again? Not a smart thing to do no matter how cheap and easy that oil change may be.

You know what is cheaper and easier? Leaving the correct oil in the motor and going 15K, lower wear, higher reliability and less work and money.

Of course if you want to throw money away and increase wear by all means there are plenty of us standing by ready to rebuild the head on your PD motor and serve you with a bill for around $2000 depending on the extent of the damage you did.






I'm not 100% sure if my case is the reason, but the previous owner did OCI's every 5-6k per "the dealer" until i bought it w/ 183k. Now at 217k, a compression test yielded very low compression (barely w/in spec). I would say it's plausible that the shorter OCI's caused faster wear of the piston rings than normal. Not to mention, after 50k miles if you change every 5k you've paid for 5 extra oil changes.

interesting! the thread is here:
Changing the oil to often? - TDIClub Forums


makes for good pondering... any opinions/ experience, guys?

[coastie]

Running a PD motor in a perpetial state of detergency has got to be the worst thing you can do to these motors. You want to allow the dispersants to do the job of keeping an engine clean and not continually flush it with detergants. Ever look at the hands of somebody with OCD, not pretty now imagine what is going on in your motor. By changing every 5K the additives have just started to stabilize and now you dump the oil and spike the detergants again? Not a smart thing to do no matter how cheap and easy that oil change may be.

How does the hands of an OCD person possibly relate to the inside of a diesel engine. Emotive statement but hardly of any benefit or factual evidence.

If the additives are just starting to stabilise at 5000 kms were they unstable previously and what does unstable actually mean. I don't know the credibility of the poster on the tdi club but it doesn't hold a great deal of fact or evidence for my value. If oil has to progress through a stabilising area/time/usage is it better at some point during this progression. There are many thoughts on this discussion but it comes down to personal preference, financial ability.

[gldgti]

coastie,

engine oils (particularly diesel oils) contain detergents to clean the inside of the engine. The idea is that as the oil runs around inside the engine it picks up any foreign matter, soot particles and dirt, and these are trapped in the oil filter. By their very nature, detergents are "unstable" chemicals - in the sense that they have a basic pH and are corrosive. It is well known that alluminium alloys are easily corroded by basic solutions - an extreme example can be seen by placing some aluminium foil into a solution of drain cleaner (sodium hydroxide). The aluminium will quickly dissolve and there is even a fun release of hydrogen gas.

There are many, many aluminium parts in the modern vw diesel engine, and anything that comes into contact with coolant or oil is going to be susceptible to corrosive wear if the oil or coolant is basic. This is why coolant is mildly acidic (if your ever unlucky enough to get it in your mouth you will taste it, but it is also poisonous).

The important part is that if the interior of the engine is a little dirty, then the detergents in the oil are "used up" over time - like if you only add a little dishwashing detergent at the start of a big wash and never add any more, eventually the ph of the water goes back towards neutral and the suds dissappear - you need to add more detergent to keep washing the dishes. in the same way, it is by design that the engine oil runs out of detergents a certain way into its life cycle, so that no corrosive wear can occur. This is why if you lived in inner city sydney, you wouldnt use diesel engine oil in your petrol car, but perhaps if you were a farmer, you could with no ill effects, because the operating environment of the engine is so bad that it literally gets very dirty (inside and out - air cleaners can only do so much).

the "OCD hands" example is actually not a bad one, as it highlights the damage that too much washing in a basic ph solution can do to a naturally slightly acidic environment (your skin).

having said all that - everything in moderation. I generally used to change the engine oil about every 5-6000km where the service interval was 7500km (for a 1994 VW diesel). Now, the oils are so good and I am using fully synthetic, I change it every 10-12000km.

[Buller_Scott]

How does the hands of an OCD person possibly relate to the inside of a diesel engine. Emotive statement but hardly of any benefit or factual evidence.

If the additives are just starting to stabilise at 5000 kms were they unstable previously and what does unstable actually mean. I don't know the credibility of the poster on the tdi club but it doesn't hold a great deal of fact or evidence for my value. If oil has to progress through a stabilising area/time/usage is it better at some point during this progression. There are many thoughts on this discussion but it comes down to personal preference, financial ability.

the ''factual evidence'' seems to be scattered throughout the thread in the link i posted, people saying that used oil analisys shows that there is not significantly more debris in 15,000 mile oil than in 5,000 mile oil [or something like that], and yet to re-introduce those ''detergents'' overly frequently is contributing to cam lobe wear in post-alh PD motors.

tdi club is pretty credible. i dont think much emotion went into the UOA etc... but it's making me think twice about changing the oil myself every 5,000km's in my PD polo, just like i had convinced myself i would...

[Transporter]

Well, US motorists are known for experimenting with using not approved engine oils in PD engines. They did so many UOA trying to prove that Mobil Delvac 1 and other not VW approved brands could be used in PD engines, and many of them ended up with worn out valve train components.

Of course everything with moderation, but clean oil will not harm the engine, even if you change it every day, otherwise it would mean that if you pour new oil in the engine and didn't drive it at all it would corrode and the oil would leak out. Keep in mind that some brand new cars get sold after 2 years of production.

As well as detergents, engine oils also contain anti corrosive additives, like I said everything in moderation.

Here is what corrodes the engine internals;
Sulfation/Nitration occurs as a portion of the engine exhaust gets ingested back into the crankcase and the lubricant bonds with the gases, forming sulfates (sulfur compounds) and nitrates (nitrogen compounds) in the oil. The compounds attack metal surfaces and cause metal corrosion.

That's why I change the engine oil 5-7,5k km

[Greg Roles]

Interesting take........I figure in an oil cooled turbo motor, oil breakdown via turbo heat is my biggest concern, thus I'm sticking to about 7500kms. I also believe the lions share of any wear happens in the first few hunderd kms after you buy the car, where it should be run in hard, but properly. Who really knows, but I firmly believe manufacturers are under great pressure to increase their service interval kms all in the quest for sales against the competition.

I figure I'm going to wear my engine out via excess nm long before oil is the problem !

[coastie]

from the same thread immediately before the quoted post

"Politics, sex, motor oil: the three topics most likely to yield nonsense and bad advice on the Interwebs? [g]

Just a quick comment: "detergent" oil does not, contrary to popular belief, contain dishwashing soap or the equivalent [g]. It does not "wash" anything. Instead it holds dirt particles in suspension, which is why it gets darker in color faster than non-detergent oil (if you can even find such a thing these days), which lets the particles settle out."


Not wanting to incite anything but I just have my feelings about emotive posts. The TDI post is a good read just the OCD comparison struck me as unusual parallel.

[Transporter]

from the same thread immediately before the quoted post

"Politics, sex, motor oil: the three topics most likely to yield nonsense and bad advice on the Interwebs? [g]

The TDI post is a good read just the OCD comparison struck me as unusual parallel.

+1 I couldn't agree more.

[Buller_Scott]

from the same thread immediately before the quoted post

"Politics, sex, motor oil: the three topics most likely to yield nonsense and bad advice on the Interwebs? [g]

Just a quick comment: "detergent" oil does not, contrary to popular belief, contain dishwashing soap or the equivalent [g]. It does not "wash" anything. Instead it holds dirt particles in suspension, which is why it gets darker in color faster than non-detergent oil (if you can even find such a thing these days), which lets the particles settle out."


Not wanting to incite anything but I just have my feelings about emotive posts. The TDI post is a good read just the OCD comparison struck me as unusual parallel.

well i can sense already that you've got a much better understanding about this than me- i just stumbled across that thread and my brow furrowed at some of the things that i read.

what i gathered from that thread, the wisdom of the ALH engined tdi'ers having being ''pushed'' onto PD owners -> very frequent oil changes -> needing head rebuilds at some stage earlier than others who've stuck to normal intervals-> mechanics telling those PD folks ''okay, we've rebuilt your head, now it's all about ensuring engine longevity, so at most frequent, only change the oil every service interval [they say 15k miles, i think?]."

i also saw the posts that stupilate, with evidence, that there is no additional amount of harmful debris in the UOA of 15,000 mile old oil, when compared with 5,000 mile oil, and thus [and in avoiding over-introduction of the detergent elements of oil] there should be no true advantage to replacing oil, other than every 15k service interval.

im all for 7,500km self-done oil changes. i'd have been willing to do it every 2,500kms myself, as i want this little polo to last for a LONG time. but do you guys really reckon that there is not much stock to be placed in the "oil changes too often -> faster engine wear -> having to be rebuilt sooner than an engine that has only stuck to normal oil change intervals"?

cheers,

scotty

[Transporter]

What this UOA don't test for is sludge and varnish accumulated inside the engine and debris stuck to it.
I fitted additional bypass oil filters in some (not VW) vehicles and owners still come for 10,000km oil change. Their cars done well over 300,000km with no ill affect from the clean oil.
I have oil bypass kit (AMSOIL bypass oil filter bigger than Ryco Z9 filter) and oil accumulator ready to go in our Tig when it arrives and am not worried about fresh oil harming the metals in the engine.

Scotty you can get more reliable knowledge from the places like this.
Automotive - Resources And Advice

It is important to remember that what you read in the discussion forums in not always correct and one needs to sort out "rubbish" from "the probably truth" and work on it, questioning it further until you get the right answer.

[gldgti]

from the same thread immediately before the quoted post

"Politics, sex, motor oil: the three topics most likely to yield nonsense and bad advice on the Interwebs? [g]

Just a quick comment: "detergent" oil does not, contrary to popular belief, contain dishwashing soap or the equivalent [g]. It does not "wash" anything. Instead it holds dirt particles in suspension, which is why it gets darker in color faster than non-detergent oil (if you can even find such a thing these days), which lets the particles settle out."


Not wanting to incite anything but I just have my feelings about emotive posts. The TDI post is a good read just the OCD comparison struck me as unusual parallel.

fair enough, and not a lot of chance of inciting anything but good discussion in our cosy little corner of the forum. I do realise that oil doesnt contain dishwashing liquid (i use dishwashing liquid to get engine oil and grease and dirt off my hands almost every weekend, such is the life of keeping 3 cars over 15 years old running by yourself). Perhaps I underestimated the readership and oversimplified my expanation - I only indended to bring conceptual understanding, and in this I do not believe I have been in error -

engine oils (particularly diesel oils) contain detergents to clean the inside of the engine. The idea is that as the oil runs around inside the engine it picks up any foreign matter, soot particles and dirt, and these are trapped in the oil filter

and transporter, sorry to be picky, but

otherwise it would mean that if you pour new oil in the engine and didn't drive it at all it would corrode and the oil would leak out

is not what i was trying to explain. Any corrosive component is "used up" whenever there is a reaction, and thus the concentration of corrosive chemicals in solution (if allowed to react) will decrease logarithmically (I am trying to say "upside down exponential curve") over reaction time. I do, however feel that it is likely that any troubles would be more realistically attributed to using oil that contained the wrong friction modifiers or lacked them completely, as you say. I only pick this up because I dont want to you to publically interpret what I have said wrongly.

[Transporter]

fair enough, and not a lot of chance of inciting anything but good discussion in our cosy little corner of the forum. I do realise that oil doesnt contain dishwashing liquid (i use dishwashing liquid to get engine oil and grease and dirt off my hands almost every weekend, such is the life of keeping 3 cars over 15 years old running by yourself). Perhaps I underestimated the readership and oversimplified my expanation - I only indended to bring conceptual understanding, and in this I do not believe I have been in error -


and transporter, sorry to be picky, but is not what i was trying to explain. Any corrosive component is "used up" whenever there is a reaction, and thus the concentration of corrosive chemicals in solution (if allowed to react) will decrease logarithmically (I am trying to say "upside down exponential curve") over reaction time. I do, however feel that it is likely that any troubles would be more realistically attributed to using oil that contained the wrong friction modifiers or lacked them completely, as you say. I only pick this up because I dont want to you to publically interpret what I have said wrongly.

You're 100% correct in your post. I didn't say that you were wrong, and wouldn't want anyone to interpret it like that.

I simplified my expression and said it in the way that even not mechanically minded reader would understand. I also said that "as well as detergents engine oils contain anti corrosion additives."
Just to be complete in what I mean that you're 100% correct is that we both know, and almost everyone who does his own oil changes that, there are anti corrosion additives in the oil and properly formulated approved engine oil can't corrode the engine unless is too old or incorrectly stored and additives in it are depleted. And yes, if there was just detergent without anti corrosion additives the metals in engine would corrode.

[gldgti]

hehe, i think, finally, we are all 'clear'.

[coastie]

Yes the detergent comment wasn't mine but in the quote from the other forum.

[Buller_Scott]

hey guys, thanks for explaining it to me, and especially for the back-and-forth! always educational.

now that im a ''man of leisure" [unemployed derelict bum], im really, REALLY getting into the whole educational side of owning a tdi for sure!

thanks also, transporter- i didnt realise that UOA didnt test for internal sludge/ debris.... and that was definitely the thing that i was most ''concerned'' with, in my effort to do what's best for the little hairdresser's car.

so it's looking like regular 15k services, with self-done 7.5k oil changes in between

cheers guys!

scotty