I have a 96 a4 with 120,000 miles, and was on the a4 forum, but since so many have the 1.8t there i decided to post this here as well.
I want to remove the sludge from the engine, and some swear that by draining oil, leaving old oil filter and flodding engine with diesel overnight, adding new oil filter and cheapo oil idle for 10 to 20 min and then adding "Good Stuff" works Miracles, i am inclined to try this but before i do, what does the forum think?
Thanks =)

far though.

<ul><li><a href="http://forums.audiworld.com/a4/msgs/2514238.phtml">http://forums.audiworld.com/a4/msgs/2514238.phtml</a</li></ul>

you'd run a serious risk of clogging the oil filter and oil passages, resulting in catastrophic lubrication failure. Diesel fuel is not a good lubricant (lack of protection from wear) and running it instead of engine oil is a bad idea. I'm against using any aggressive solvent in the crankcase. You risk damaging bearing seals, which are already old. Removing sludge will also very likely remove some false seals, causing oil leaks.

First of all, find out why your engine is sludged (Do you KNOW there is a sludge problem?):

- wrong oil (cheap mineral oil, wrong viscosity etc)
- oil change interval excessive in regard to driving conditions (short distance driving, cold/hot weather all the time)
- PCV system not working properly (sludge maker #1!). Check all breather hoses for clogs and tears, mesh filters in valve covers, plenum

Fix what needs fixing and change the oil and filter. You may want to use an engine oil with a large amount of detergents. That means a mixed fleet oil (rated for gas and diesel engines -- never use an oil that is rated for diesel engines only!) will work to your advantage. Do a few early oil changes. Since it can be presumed that the engine has been somewhat neglected for a long time (otherwise it wouldn't be a sludge monster), you may then want to switch to a high mileage oil, for example Valvoline Max Life 10W-40, which contains seal conditioners that may help with seal life and oil consumption issues.

i use Mobil 1 , previous owner didnt use a lot of the proper fluids and proper coolant. Some guy's from europe swear by this technic, they claim that diesel is a really good cleaner; in fact they claim that you could technically put reg gas or even thinner, but they are highly volatile, they recomend then diesel and they swear by it, in fact they calim to do it all the time.
Maybe i'll try it and post some pictures, but im weary in trying this one.
Thanks forum<ul><li><a href="http://M">http://M</a</li></ul>

Well, this European here thinks it's a bad idea due to the aforementioned reasons. Of course, do whatever you want.

PS: The use of conventional oil by itself, if used with an appropriate oil change interval, will not cause sludge in the 12v engine.

I have been thinking of changing to this oil (Valvoline Max Life 10W-40) for some time now in both my 12v's. I have just had such a good track record with Castrol GTX 10W30/40 for so long that I am finding it hard to do the switch.

Old dog and new tricks syndrome.

And thinning the oil out that much when running the car... hard on bearings, let alone what you might now be circulating to and through the engine and bearings....
Bad...
Just change your oil when it's hot, and do this more often for a while.

got a killer deal today. Autozone is running a special with Castrol Motor Oil when you buy a Fram Oil Filter; this includes syntetic oils.
Autozone sells a Castrol Syntec specially made for europeans 0-30 made in germany, i just tossed that fram filter but got the discount on the oil, and used a mobil 1 filter. Hope this helps and thanks to the forum...
Cheers =)

You could burn a lot at startup.

I have used 15W-40 Delo for a long time. I have 165k on my A4 and it uses virtually no oil between changes.

directly to the cranck case and change oil with mobil 1 synt.
Thanks

Every oil gets the thinner the hotter it gets.

There is no such oil that is "too thin" at startup -- any oil, even a 0W-X oil is "thick" when cold. A thinner oil (still not "thin" at low oil temps!) provides better lubrication than does a thicker oil due to less resistance to flow during startup and before reaching operating temperature.

The Castrol oil in question has an HTHS of &gt;3.5, which means this oil meets the high temperature shear resistance requirements mandated by VW/Audi for this engine. This is reflected in this oil's approvals, which include VW 502 and ACEA A3. Other 0W-30 oils, including the US-made Castrol 0W-30, may indeed be "too thin" (HTHS &lt;3.5) at elevated operating temperature.

"GC" 0W-30 may be less than ideal in an older VW/Audi engine, since this oil does not resist blowby (at rings and valve stem seals and guides) very well -- none of the full synthetic oils excels at that! Reducing blowby via an oil that starts out very thick (15W-X, 20W-X etc) is a Band Aid fix, no more.

The challenge is to find an oil that

1. provides optimum lubrication
2. keeps the engine clean
3. minimizes consumption

Depending on engine condition (age/miles, cleanliness, driving conditions, climate), ideal oil choice may vary from a full synthetic Group IV or V to a Group III or to a mixed fleet HDEO.

It's a slippery topic. :-P

i really like this oil and not to be a smart a.. here but i like the fact that it's made in germany and must likely used in many Audis, plus the fact that it's cheaper when on special than Mobil 1, now which one is better do? Mobil 1 or this Castrol syntec? Basically is it on a preffered basis?
Thanks

low insuficient egr code im getting?, the problem in doing this is that my neighbors are old guy's (with out a life) and are on top of everything with the association, i even have to change my oil with the garage door close because they like to check on things, and even do it's my home i cant according to them fix cars on the premisses....what a joke; you know they think they own the place just cause there on the board, "kind of like what happend to morty seinfeld =)=)
Thanks

.. by letting the engine suck in small quantities of fluid through, for example, the brake booster hose into the intake manifold. Use the method described on the can, but be aware that this process may (or may not) create a lot of smoke. You might end up fogging an angry neighborhood. I suggest you do this at a friend's house. ;-) Be advised that all the carbon that gets removed goes through the cats and also exposes the O2 sensors to contaminants.

The "low insuficient egr" code that you get is possibly due to a clogged EGR passage. You may have to clean that out manually. The Seafoam treatment won't help there.

<a href="http://www.mnsi.net/~natwhite/audi/egr.html">EGR and intake cleaning</a>

As I previously said, I'm not a fan of adding any solvent, including Seafoam, to the engine oil. If you do add Seafoam to the oil, follow the instructions. Idle the engine for a while, then change the oil and filter. I'm seriously in favor of just using using a decent mixed fleet oil and more frequent oil changes, which will also clean up the engine.

"GC" is a very good oil, but I don't believe it's an ideal oil in the 12v, unless your engine is brand new and very clean. GC 0W-30 is probably a better oil than M1 0W-40, which is comparable. The reasons for saying this are based on having seen many used oil analyses involving those two oils. Unlike M1 0W-40, "GC" 0W-30 does not tend to thin out (as much) and holds up better due to its allegedly superior chemistry. "GC" has rabid followers, many of who have formed sort of a cult around "GC." You can find all the info on "GC" there:

<a href="http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=718643#Post718643">The Crazy "GC" Cult</a>


With warmer weather approaching, I suggest you use one of these oils (in no particular) to help clean up your engine:

Shell Rotella T 5W-40
Chevron Delo 400 15W-40
Mobil Delvac 1300 S 15W-40

I would do a couple oil and filter changes over the next 6 months. Then I would evaluate cleanliness of the engine (Have you ever taken the valve covers off?) and oil consumption before deciding on what oil to use from then on.

Whether or not a Seafoam treatment will foul the plugs depends likely on their preexisting condition. If the plugs are in good shape, the Seafoam treatment shouldn't affect them sufficiently to foul them, but if the plugs are already in poor shape, the Seafoam treatment might worsen the plugs' condition.

Spark plugs, can self-clean to a degree, if the engine is driven hard ("Italian tune-up"). In case of a fouled plug this may not be possible. After resorting to fairly drastic engine cleaning measures, I would probably just install new spark plugs.

0 weight oil means it has the same viscosity as water. Literally!
While it may get to the components quicker upon start-up, the better questions are:
1) Will it stay there when the car is idling or turned off?
2) Was the engine's clearances designed for 0 weight oil? (no!)
The oil pump's pressure regulator will be stressed to keep up with the demand for oil pressure with the viscosity being the same as water.
Newer cars are being developed to use 0W oil, they have "tighter" engines.
As an engine wears, the clearances get bigger (further apart). So you should actually be adding thicker oil as the engine ages!

I suggest running 15/40 or 20/50 if you have over 150k on the car, otherwise stay w/ the recommended oil weight. (10/30).
Go thinner in the winter (easier start up).
Thicker in the summer (stays thicker longer).

what i put in mine last time fwiw...
never used it before no opinions yet..

false knowledge. I don't have enough time and interest to elaborate.

that's the being married dont have money way =)

If this were a brand new 12valve or even a 30 valve I would say go for it. The 12 valve was designed in the mid 80's before low weight synthetics became popular.

OW oils can turn a small oil leak into a bigger one. That 30W is not thick enough at high temps either.

I know we should all rebuild our engines back to original spec but most of us won't be doing that.

Newer engines with turbos and VVT need low weight synthetic. (I have it in our V6 Toyota)

While we both agree on 0W-x oils not being ideal for at least most 12v engines, I do disagree with most of your reasoning, which appears to be based on common misconceptions. I don't mean to belittle your opinions, but they do fly in the face of facts. Please do not take what I'm saying personally.

<b>The 12 valve was designed in the mid 80's before low weight synthetics became popular.</b>

That has however nothing to do with the facts regarding the suitability of a modern engine oil. Let me explain why: a 0W-x oil is THICK when cold (ambient startup temperature). Look at kinematic viscosity charts if you do not believe me. A cold 0W-x oil is THICKER than a straight 40 oil is at operating temperature. An engine oil simply cannot be too thin at startup!

A 0W-30 oil is thinner at very cold temperatures than a 10W-30 oil. ALL oils, regardless of their viscosity starting point or range, get thinner with increasing temperature.


<b>OW oils can turn a small oil leak into a bigger one.</b>

That has very little if anything to do with an oil's viscosity! It has to do with 0W-x oils being full synthetics that tend to creep past seals more than mineral or hydrocracked oils do. 0W-x oils are also full synthetics, which may remove false seals (crud on leaky seals), thus increasing leakage.

<b>That 30W is not thick enough at high temps either.</b>

That is absolutely not correct. This particular 0W-30 oil has a High Temperature High Shear (HTHS) viscosity of &gt;3.5, which is specified for the 12v engine. Look at the kinematic viscosity of this oil and realize it is a very thick 30, almost a 40. Most oils will thin out one or two grades over common oil change intervals. The "GC" in question thins out less than most other oils and will generally remain a 30 throughout the oil change interval.

VW oil specs are backwards compatible. VW 500.00, which was originally specified for the 12v engine has been superceded by VW 502.00. "GC" is officially approved by VW as VW 502.00 oil.


<b>I know we should all rebuild our engines back to original spec but most of us won't be doing that.</b>

I agree that worn valve shaft seals and valve guides contribute to oil consumption if 0W-x oils are used. I will add that the loose tension ring design and the PCV system in the 12v contribute greatly to oil consumption.


<b>Newer engines with turbos and VVT need low weight synthetic. (I have it in our V6 Toyota)</b>

This has nothing to do with smaller bearing clearances, which is at what you hinted in yesterday's post. Bearing clearances have really not changed over the past 30 years. Tolerances have gotten smaller due to improved manufacturing techniques. Flow is what's essential to proper engine lubrication. Modern engines are designed to minimize frictional losses. In that context, remember that oil pressure is nothing but resistance to flow.

Now I ask you, why do you believe a 0W-x oil is too thin at common ambient start-up temperatures (sub-freezing to hot summer day)? How can that possibly be, since the oil is actually much thicker when it's cold compared to when it is protecting the engine in its hot and thin state just fine?

Maybe not.

Leaks and oil burn are important. If a car has spent most of it's life running dino oil converting it to synthetic may not be everything you wished for.

I verbatim said to rusf77:
<a href="http://forums.audiworld.com/12v/msgs/67396.phtml">"GC" is a very good oil, but I don't believe it's an ideal oil in the 12v, unless your engine is brand new and very clean.</a>

Based on what he told me about his engine, I proceeded to recommend one of these oils:
Shell Rotella T 5W-40
Chevron Delo 400 15W-40
Mobil Delvac 1300 S 15W-40

I have no issue with you advising against GC or any other oil -- but the reasoning behind such advice must be based on facts.

I was right all along , but for the wrong reasons.

Aren't you using 5W-55 or something in your 12 valve?

After trying out several oils over the past 11 years, I went back to using Castrol 5W-50, which has always performed very well in my particular engine. That's hydrocracked Group III "fake" synthetic oil. It costs unfortunately the same as most full synthetic oils, so it's somewhat of a rip-off.

I believe Valvoline Max Life 10W-40 is a good choice for most 12v engines, especially considering this oil meets ACEA A3 (the basis for VW 502.00) and that its price is right.