AEL Zahnriemen gerissen. Nockenwelle viermal gebrochen! | Posts 32+

"The fracture surface appears somewhat unusual. The middle section shows corrosion at the fracture point. Also, the fracture surface on the right side is very smooth. This smooth area could represent a crack where the two halves have rubbed against each other (due to vibration), causing the surfaces to become smooth (it could also be a hardened crack!). The corrosion point must have been an old weak spot that certainly contributed to the fracture."

Regards, Peter.

I agree! The matte was probably old and ultimately caused the damage.

'This might not be directly relevant, but a friend's Corsa (gasoline engine) had a problem with the valve lifters 1000 km after a timing belt replacement. In that case, 7 valves were bent. There was nothing visible on the pistons, just like in your situation. We replaced the cylinder head, and that solved the problem! The car runs exactly like it did before. Hopefully, this gives you some encouragement!'

If I'm not mistaken, the camshaft has the part number 074 109 101 J and costs around 350 euros net when purchased new from VW/Audi.
Valves: Intake valve 046 109 601 J, approximately 25 euros.
Outlet 046 109 611 F, also around 25 euros.
Hydros: Piston 034 109 309 AD, approximately 20 euros + small parts like spring washers.
Valve springs, etc.
But be careful! Some items are only available in packs of 5 or 10.
But without any guarantee!

In my opinion, you would be better off using a replacement cylinder head. Plus, the replacement cylinder head still has a warranty! I would probably install the replacement cylinder head. It should generally come with new valves, lifters, etc.

kmrlange wrote:

Regarding the piston: You probably mean the connecting rod bearing in the piston, which is located on the "ears." or both? I'll try to measure the overhang.

Well, it could have received everything or nothing at all, and that could go all the way up to...
"The pleats are compressed, as mentioned above. There's not much you can do about it."
The game might happen, but if it does, it's probably bad. If it doesn't, you might be lucky.
But it doesn't look that bad yet; I've seen much worse.
I saw where the valves are mounted directly through the piston. It seems like most of...
"Did your hydrostatics fail? I've seen worse on a Polo before."
He was also a Benz enthusiast and owned several vintage Benz cars, which he acquired new.
plus a few updates, and then it worked again without any problems.

Okay, so a "hydros" used to cost around 35 German Marks each, if you bought them from someone directly.
"Valves can also cost anywhere between 15 and 60 DM each, depending on the model. A head needs to be..."
actually, it shouldn't be, as long as the valve stem guides are not broken, and since...
"The valves, being located deep within the cylinder head, are unlikely to have been affected."
Four valves were broken because they were severely bent during the crash.

I wouldn't worry too much about the head.

Hi,

Thanks for the tips. I'll try the fuel leak test tomorrow.
But I also think a replacement head is probably a better investment. And the risk is...
then gone.

Since everything is already exposed, how about taking a look at the oil pump?
170,000 km mileage?
Does it always stay at the AAT/AEL level?


Einen Brief an AUDI SERVICE habe ich schon abgeschickt. I'm excited.
Here's the translation:

'Let's see what they have to say about it. Not everyone takes their vehicle apart at home, after all.'
and then demands leniency. I will, of course, report on this in detail.

Best regards, kAi.

Hi,
It took some time, I was on vacation.
It looks like a fatigue fracture: The crack started in the right, smooth area. The left, grainy area held out for a while and then fractured in a brittle manner, which was the moment the engine stopped. The smooth surface is oriented almost perpendicularly to the tensile stress, which resulted from the force between the metal nose and the engine block. (Hopefully, that makes some sense.)
I can't comment on the corrosion. However, the fracture likely didn't occur there because, under the assumed load, there would be very little stress in that area.
In any case, Dauerbruch claims that this was the cause of the problem and that the tensioner pulley did not break due to some other damage.

Hello there,

I received the first response from Audi today regarding my goodwill request.
Most people probably already suspected it. It all revolves around definitions of terms:
Unfortunately, but etc., and of course, I'm supposed to be understanding. I am - in vast quantities.
Only in a way that shows a lack of understanding for cheap, low-quality goods.
Perhaps expensive drive systems are being presented to AUDI customers by the customer service department.
Figuratively speaking: Now the battle for MORDOR begins, and I'm standing before the black...
Tor.

I'll post the first AUDI response tonight.

P.S. Thank you for the detailed fracture analysis.

Best regards, Kai.

Hi again,

Here is my cover letter, with a request for review, for my application to AUDI:
http://people.freenet.de/kmrlange/Kulanz_Anfrage_01.pdf

and here is the first response from AUDI SERVICE:
http://people.freenet.de/kmrlange/Audi_Antwort_01.pdf

I am grateful for any tips or suggestions regarding the setback, especially those that offer a promise of success.

to be continued... Best regards, KAi

Hello neighbor,

I don't think you'll let that slide.
Sure, I will translate the text from German to English. Please provide the text you would like me to translate.
Regarding the engine, you can't expect any goodwill due to its age and mileage. However, you might be able to get some goodwill regarding the defect in the tensioner pulley (although it's also 3 years old). Since this breakage led to a serious consequential damage, you can usually demand that the vehicle be restored to its previous condition. Theoretically, this would mean installing a comparable engine. However, the problem remains in determining the "original condition" and assessing it. It's important to consider the engine's intended lifespan and how much of that lifespan it has already used. I would recommend consulting a qualified automotive expert (I might be able to recommend someone in the area). It's crucial to gather evidence in this case.

That sounds like it could be a difficult task. Please keep us updated.

Hello everyone,

Okay, the project is moving forward. All the spare parts are available, including a new cylinder head.
It looks absolutely amazing. I'll let you know how it goes.

I have two questions to start with.

1) Does anyone have an old AAt/AEL timing belt that I could use to practice installation?
(regarding the genitive case) could be used, but ideally, it shouldn't.
to be torn I have that one myself.

2) Based on experience, is there anything specific one should be aware of regarding the entire process of ZK (presumably referring to a specific procedure or system) and ZR (likely another related procedure or system)?
which you particularly enjoy getting wrong? (e.g., reversed order of Mondays...)

Best regards, Kai.

Yes, the tensioner rollers on the five-cylinder engines are prone to breaking at that point. I've personally worked on about 28 engines (mostly T4s), so I've seen this happen quite a bit.
Regarding the oil pump: The pump is very durable and hasn't shown any damage yet, but the seal to the engine block sometimes leaks oil, essentially providing continuous corrosion protection for the engine. However, to remove the oil pump, you'll need to unscrew the oil pan.
The connecting rod bearings were fine (which would be a first for me).
Rebuild the cylinder head; it will cost roughly the same amount.
Have fun assembling it.
If you have any questions, feel free to ask.

Hi,
You can start to feel scared.
@mersente:
Do you have any idea if there's any correlation between the time the tension rollers broke and the year the building was constructed?
The timing belt(s) in my car are also due for replacement soon, and since I've always had all the pulleys and water pump replaced at the same time, I'm now wondering how much sense it makes to do so, especially if there's currently a quality issue with the tensioner pulleys. The previous ones lasted for about 90,000 to 100,000 km without any problems.

Best regards from Berlin.
Olli.

Hi Olli, don't worry too much about it; it mainly occurred with the ACV engine in the T4.
With my Audi AAT or AEL, I've only experienced that twice in 5 years.
In some T4 models, the tensioner bearing would sometimes fail at as low as 37,000 km, which is obviously alarming.
The affected tension rollers have been replaced, but they still have 'Canada' printed on them.

Hi,

@mersente: Thank you for the assistance. has been slightly modified on the AAt/AEL tension rollers.
become? Because, as mentioned before, even if I want to be absolutely sure...
and I would have wanted to change it after only 60,000 km (half the interval).
57,000 km driven.

I once measured the piston protrusion at top dead center. The result: There was no difference.
five pistons can be measured. Therefore, I am also assuming an unaffected crankshaft.
I ordered the upper half of the engine (which was expensive enough).

This new cylinder head looks absolutely fantastic. Almost too beautiful to install.
Is there a way to tell, based on a part number, whether it's a replacement part or a brand new part?
He certainly looks fresh and innocent.

Do the screws for the two pulleys on the camshaft also need to be replaced?

Best regards, KAi.

Hello, you can identify the replacement part by the mandatory yellow sticker with the part number, which will have an 'X' at the end. Otherwise, you won't be able to notice any difference compared to a new part, except perhaps in terms of price.
To the best of my knowledge, the tension rollers have been changed, even though they are still manufactured in Canada.
I usually change the timing belt around 90,000 km, although I think the recommended interval is 120,000 km (but it's better to be safe than sorry).
Okay, one more thing: There's a diamond disc that's practically mounted between the crankshaft gear and the crankshaft (actually, only on LT models).
This disc will also fit your device. I will come by tomorrow with the part number.
The diamond disc prevents wear on the crankshaft at the contact surface of the timing pulley sprocket, which would otherwise lead to your problem: namely, that the valves would hit if the crankshaft sprocket slips on the crankshaft.

Hi,

The crankshaft stub still looks to be in good condition. The corresponding part on the timing belt pulley is also fine.
The problem isn't with the wheel well liner slipping. The connection is lost during the AEL (Automatic Emergency Locking) process.
a tongue-and-groove joint is formed, not through a flattening on the crankshaft as in the...
1Z to pencil.
In what way can this diamond disc prevent chipping?
If the screw connection loosens, both parts will strike the diamond disc.
and the damage must be similar to what would occur if they collided directly, right?

And what should I do with those two rear wheel screws? Should I replace them or not?

Do you happen to have an old ZR Mersente lying around?

Best regards, KAi.

Hi, I don't have an old timing belt right now, but you can definitely use the new one for testing. It's not that difficult to install, just be careful not to kink it. You can reuse the screw for the camshaft pulley.
I'm not so sure about the screw for the crankshaft sprocket.
Okay, so if it's tightened to 460 Nm, you can reuse the old one, but you must apply a thread locker (liquid) to it beforehand.
If the screw is tightened to 160 Nm + 270 degrees, you will need a new one, which should be installed without any locking mechanisms.
Normally, you don't need the diamond cutting disc, but it certainly won't hurt to have it, since it's also used by the manufacturer in newer LT five-cylinder engines.
I hope you're replacing the water pump too.
First, attach the vibration damper with the crankshaft pulley, place the timing belt around it, and then assemble everything onto the crankshaft, making sure the belt goes around the tensioner and over the water pump.
Then you take the camshaft wheel and place the belt on it. Then you slide the crankshaft pulley onto the camshaft (of course, everything is aligned at top dead center) and tighten the screw with two fingers.
Then you tighten the tensioning roller, check that everything is aligned to the OT (optical target) position, and tighten the NR (noise reduction) component with 100 Nm of torque, securing it with the counter-holder.