Conversation of /Catastrofic motor failure, information/count.

[Justincredible]

This thread is for the conversations related to the results from the Catastrofic motor failure, information/count. post. This thread is to help keep the post clean and on topic for members to put there information in.

Here is where you can share your thoughts.

Thoughts to this thread.
-A-catalog-of-major-motor-issues-Catastrofic-motor-failure-information-count.

Its quickly emerging that there are issues. We don't want people to think there are major issues but cataloging the motor issues that have come up in the past are showing several things that people need to look for and be conscious of.

OIL 101

In the All aluminum motor of the b6/b7 S4 its looking like more and more that oil can play a serious roll in keeping the motor happy. Several parts that can fail depend on Oil.

We have had several conversations on the cam tensioners and cam adjuster. These are both oil fed and depend on oil to keep them healthy. The entire motor can take 20 min on a initial cold first start to pump up the entire lifter and oil system through out the entire motor.

A few things were going to talk about in this post. Service intervals for oil change. I feel 5000+ or even 10,000 is crazy even if you drive like a old softy. There is too much that depends on the motor and its looking like more and more the motors that have a long life have the best Synthetic oil in them.

This post is directly linked to this post

[SquiddyB6S4]

Another suggestion, can we make this thread also into a poll? Maybe "Have had engine replaced", "Have not had engine replaced, but am under 80k miles", "Have not had engine replaced, and I'm over 80k miles"

[dparm]

Before this turns into the ridiculous fearmongering that was the chain tensioner thread, we should probably put a big fucking disclaimer in here that says the failure rate is astronomically low and this is not even close to the BMW E46 fiasco or anything like that. No need to scare people into thinking these motors grenade at 80k.

Also, for the sake of education, I think everyone needs to post how the car was treated. Driving style, how many owners, maintenance records, etc.

[jfunkey]

Something to think about.... On the 2.7T we thought the same thing back in the day. It was thought that you didn't need to do the timing belt till well into the 80k+ mark. This turned out to be not true and it was and is a
serious issue. Now some cars went till 100+k. So we might have some serious issues and we make up a small collection of the audi population. Although I agree this is the largest collection of B6/B7 owners
It still is a small fraction. So this might be a litle more serious then were making it. I don't think this shuold be kept too light.. Think about it..

I like the idea of the type of driving and oil question. Keep in mind for some this car is on its 3rd owner. So there is no way of knowing that information.

While I agree this isn't a fear mongering thing as this motor is much more solid then the worry wort comunity makes it out to be but there are issues we shuold look for and maybe
The tensioners are one of them..

Oh and I do think we should sticky this thread and then have sub cattagory threads out of this.. Ie the oil thread and over all disscusion of thoughts...

[blacka4]

ok this thread scares me about buying a B6 S4....

[dparm]

^ Exactly the kind of response we didn't want, lol.

[SuperAvant]

2004 with an 02/2004 build date (purchased new - currently 114k miles).

High oil consumption developed at 110k. Compression normal, no cylinder scoring. Found a broken chain guide when after the motor pull. Replaced all the valve stem seals, chains, guides, tensioners. The consumption has dropped.

Oil changes were done every 5000 miles.

Interesting... Im trying to figure out how a broken chain guide would cause high oil consumption other than running like absolute chit. Can anyone elaborate?

[SpeedETC]

^^ The valve stem seals were the cause of the high oil consumption. The chain guide was found as part of the work. In regards to the guide, the tension from the chain was holding it in place. Once the tension was removed, we realized that the guide was cracked all the way through.

[SuperAvant]

Gotcha - didnt see the valve stem seals part. Should have read all the way through.

[blacka4]

^ Exactly the kind of response we didn't want, lol.

no doubt, but its really making me wonder if I should continue to work this deal on a S4 25quattro.

[gdawg'05a4]

no doubt, but its really making me wonder if I should continue to work this deal on a S4 25quattro.

I recently got into a 25quattro (from a '05 A4) and it has oil consumption issues (1qt / 500 mi). Though I'm working on finding out the cause right now (piston rings seem to be the issue), I still thoroughly enjoy the car every day

[SquiddyB6S4]

I do encourage people to talk to their local dealership's shop foreman about frequency of chain 4.2 issues (or the nearest large dealership; don't bother calling one that only has a few service techs). It is a small/rare issue, but if you leave out the cam adjusters, the tensioners and guides are pretty cheap, and just by looking, it kinda seems like it might be doable with the transmission removed and engine in place, but I've not got anywhere near the experience to say yea or nay on that. I'm still lightly considering it as preventive maintenance (down the road, not now). It's just a highly expensive and slow (read: lots of down time) failure, and least appears to be avoidable. But this thread is starting to make me think that maybe the pistons are the bigger problem, and that chain issues really are not something to worry about. And I certainly wouldn't rip apart my engine to go replacing pistons as preventive maintenance.

[blacka4]

btw guys, I'm sorry for the threadjack.

but one final question for you owners. Knowing now what you do about the engine and failures, would you purchase your 4.2 S4 again?

[MichiganAudiDvr]

What happened to the OIL 101 discussion? The thread and all the posts seem to have morphed into this thread, less half the posts...

[dparm]

I'm working on a more comprehensive FAQ/informational thread for people.

I'm still open to discussion until then though.

[Abwasserleitung]

I do encourage people to talk to their local dealership's shop foreman about frequency of chain 4.2 issues (or the nearest large dealership; don't bother calling one that only has a few service techs). It is a small/rare issue, but if you leave out the cam adjusters, the tensioners and guides are pretty cheap, and just by looking, it kinda seems like it might be doable with the transmission removed and engine in place, but I've not got anywhere near the experience to say yea or nay on that. I'm still lightly considering it as preventive maintenance (down the road, not now). It's just a highly expensive and slow (read: lots of down time) failure, and least appears to be avoidable. But this thread is starting to make me think that maybe the pistons are the bigger problem, and that chain issues really are not something to worry about. And I certainly wouldn't rip apart my engine to go replacing pistons as preventive maintenance.

I purchased my B6 S4 build date 10/03 with 40k miles this last winter which is why these issues were not discovered until the car was driven more. The car initially went in for a warm engine knock and possible misfires. Ignition coils were replaced first, by my instruction, in hopes to subdue the misfires and “knock” with no avail as I was reluctant at first to have the engine tore apart.

The dealership I work with who ended servicing my car had never experienced any issues with the timing chain/guides prior to my car. They mentioned a few cam adjusters due to poor oil maintenance but nothing other than that. The tech that serviced my car was a german-trained Porsche tech that relocated over here 20 years ago.

Tech’s Diagnosis: Chain Guide Failure was the root of subsequent problems later discovered. Tech stated that due to the chain guides failing it was causing the timing chain to ride up onto the gears and when the chain would then settle back into the gears it would create advance issues and intermittent misfires. This motion of the timing chain settling was also replicating a warm engine knock. Results from a compression test indicated a loss of 20% + in two cylinders. The valvetrain was tore apart to find two bent valve stems. The tear down of the block also found that a 1-2mm gouge was found in the cylinder wall on in addition to scouring.

Tech’s “theory”: The failing chain guides that created the timing chain settling as mentioned above over time put undue stress on other timing components that would eventually end up affecting the valve train. Over time the valve stems started to go causing a loss in compression in two cylinders. And due to the amount of lost compression coupled with intermittent misfires and advance issues, the piston eventually gouged the cylinder wall.

[PNW Avant]

If scored cylinders seem to be an issue, has anyone tried AutoRX? My buddy did a cycle of AutoRX on his EVO and had increased compression in all cylinders afterwards. Seems it might be able to clean out some of the gunk that may be accelerating the problem.

[gdawg'05a4]

I am currently on a Auto-Rx cycle (oil consumption application) and also some 2-cycle oil in the gasoline (3oz/10 gal). Consumption has slowed down a bit since starting this process (1000 mi so far). Before starting, she was consuming 1 qt per 500 mi. Now, it's slowed a bit, recently added a quart after 630 mi. So it has definitely improved. Oil filter will be changed out in about 200 mi so I'll get to see what kind of crap has been caught.

[PNW Avant]

I am currently on a Auto-Rx cycle (oil consumption application) and also some 2-cycle oil in the gasoline (3oz/10 gal). Consumption has slowed down a bit since starting this process (1000 mi so far). Before starting, she was consuming 1 qt per 500 mi. Now, it's slowed a bit, recently added a quart after 630 mi. So it has definitely improved. Oil filter will be changed out in about 200 mi so I'll get to see what kind of crap has been caught.

Did you do a compression test beforehand?

[gdawg'05a4]

Did you do a compression test beforehand?

Yep, so I have numbers to compare after the cycle is complete.

[PNW Avant]

Yep, so I have numbers to compare after the cycle is complete.

Great! Looking forward to seeing the difference.

[Justincredible]

I would love to see this too. I don't know if being an all aluminum motor would cause this to work better or worse

[PNW Avant]

I have been surprised to not see AutoRx come up as a step to take when scored cylinders/consumption are in question. My friend who I mentioned used it on his EVO is a very knowledgable mechanic and loves the product. Let's hope it helps!

[jfunkey]

I have been surprised to not see AutoRx come up as a step to take when scored cylinders/consumption are in question. My friend who I mentioned used it on his EVO is a very knowledgable mechanic and loves the product. Let's hope it helps!

I would like to know if it works on the aluminum as well

[MattyJ]

Just a note... cylinder wall scoring isn't caused by "piston swell" it is caused by piston skirt wear. In the past couple years they have rectified this issue by coating the sides of the piston in a new substance that's name is escaping me right now. I have seen this multiple times on other car lines as well, it is an inherent problem with using the "Alumisil" blocks. A big problem for Audi is the sludging of the oil system causing all sorts of issues. I learned from an old timer a couple years ago to add a quart of ATF to the oil at every oil change prevents sludging(it has a lot more cleansers in it) and back in the day they would clean engines like that or by adding diesel to the oil and changing the oil every 500 miles until it was clean. It sounds crazy but it works.

[Justincredible]

Just a note... cylinder wall scoring isn't caused by "piston swell" it is caused by piston skirt wear. In the past couple years they have rectified this issue by coating the sides of the piston in a new substance that's name is escaping me right now. I have seen this multiple times on other car lines as well, it is an inherent problem with using the "Alumisil" blocks. A big problem for Audi is the sludging of the oil system causing all sorts of issues. I learned from an old timer a couple years ago to add a quart of ATF to the oil at every oil change prevents sludging(it has a lot more cleansers in it) and back in the day they would clean engines like that or by adding diesel to the oil and changing the oil every 500 miles until it was clean. It sounds crazy but it works.

Not really it is caused by piston swell. its just that it can effect the skirts more then other parts. Our pistons already have Side wall coating.
Other audi aluminum motors are not having the same issues such as we are. When you look at the piston damage on many scoring motors. You can see damage from the piston and its not limited to the skirt

Also the ATF fluid to help sludge. Its just like motor clean. You poor it in and then let the motor run for 5-10 min and flush it out. You don't keep the ATF fluid in the system for longer then 10 min. And it will help.

[Justincredible]

04 s4... not sure of build date.. car has 87,xxx

all mait. up to date..

however, just recently started noticing a small oil consumption increase.. maybe this would be a good place to ask questions.. i ran a full compression test on the car and every cylinder came back 145-155. except one cylinder being at 140.. the car sounds healthy oil is changed every 5k miles. i just noticed since i did the last oil change at 85k. i have added a quart to 2 quarts of oil so far.. my car is fully catless so it does smell rather crappy. but, i have noticed a "burning oil smell" with a puff of greyish smoke from time to time (mostly on down shifts, or taking off quickly from a light)

i replaced the pcv valve thinking it could be coming from that, i have no signs of oil leaking externally from the car.. my only guess could be the piston rings possibly failing.. im not really sure.. you guys mention all this scoring etc.. are any of the signs i listed sound like it could lead to that.. i am going to either do a leak down test or oil consumption test next oil change by weighing the oil..

does anyone else have any ideas of what this could be attributed to or any insight.. would be greatly appreciated all the help i can get.. i called audi and they are no help.. didn't even call me back ::face palm::.. im not even sure how to test the car to figure out what is going on

I replyed to this in the above thread but I decided to bring it down into this post for you.

At this time you need to gather more information. See how much oil you use between oil changes. Make sure to keep the oil changes to ~3000 miles. Also send you oil out to be looked at by an oil analysis test lab. This will start to put you in the right direction.

[rlee6462]

I'm assuming high oil consumption is related the scored cylinder walls? My warranty just ran out, and it sounds like I need to buy another one!

[somethingcorp]

after doing both tests.. the results came back with nothing wrong as i had thought.. just me being cautious.. i had a compression test and leak down test preformed.. like stated above the compression test came back with flying colors as did the leak down. i replaced all pcv related items cause my dealer told me it could be attributed to a pcv related issue and may also have to do with the fact that i have a catless exhaust. the technician i had that worked on my car could not duplicate any smoke coming out of the exhaust under full load and engine breaking... i strongly recommend anyone with this type of issue check into pcv hoses and pancake valve.. since the previous post at 85k. i have now put an addition 7k miles on the car and have not had to add any amounts of oil between the change. i just recently preformed an oil change at 89k and still have not run into any problems.. hopefully this helps some of you fellas out..

[Justincredible]

after doing both tests.. the results came back with nothing wrong as i had thought.. just me being cautious.. i had a compression test and leak down test preformed.. like stated above the compression test came back with flying colors as did the leak down. i replaced all pcv related items cause my dealer told me it could be attributed to a pcv related issue and may also have to do with the fact that i have a catless exhaust. the technician i had that worked on my car could not duplicate any smoke coming out of the exhaust under full load and engine breaking... i strongly recommend anyone with this type of issue check into pcv hoses and pancake valve.. since the previous post at 85k. i have now put an addition 7k miles on the car and have not had to add any amounts of oil between the change. i just recently preformed an oil change at 89k and still have not run into any problems.. hopefully this helps some of you fellas out..

Great post nice follow up. The PCV system can really cause issues one of them being oil in the intake track

[dparm]

Just curious, who is the manufacturer for OEM pistons? Mahle?

[grease]

You posted a picture of piston swelling with the scored cylinder walls, but the scoring goes all the way to the top of the cylinder and stops about an inch from the bottom, that means it's less likely to be swelling and probably caused by a to thight of a ring end gap, which usually happens on a high performance motor from not letting the motor come up to running temp before taking off, the rings end up expanding faster than the cylinder and couse the scoring. So those of you who had engine work done, how meany of you start your car and take-of in the morning without warming up.

[SquiddyB6S4]

You posted a picture of piston swelling with the scored cylinder walls, but the scoring goes all the way to the top of the cylinder and stops about an inch from the bottom, that means it's less likely to be swelling and probably caused by a to thight of a ring end gap, which usually happens on a high performance motor from not letting the motor come up to running temp before taking off, the rings end up expanding faster than the cylinder and couse the scoring. So those of you who had engine work done, how meany of you start your car and take-of in the morning without warming up.

I have had this argument in my head before, and my final decision is that I will not let the car warm up while sitting still. Rather, I begin moving as immediately as possible (get everything ready to drive before starting engine), but keep revs and throttle angle low for a while, until the engine is warm. This way, engine load and combustion chamber temps stay rather low, but oil flow and pressure get raised, which has got to be good for both lubrication of moving parts and bringing oil up to temp.

[jfunkey]

The picture I saw showed the dammage up as far as the piston would rise. Chances are not great its from ring gap as rings float and have lots of play on these motors.

[Justincredible]

The ring gap was not super tight. While this also could be an underlining issue, the piston skirts were hammered real bad. The picture isn't at a great angle but you can see that there is the gap where the ware isn't all the way to the top

[SquiddyB6S4]

From the other thread:

'04 1 quart per 300miles.

cylinder 6 + 8 scored, low compression, oil on plugs - 5,6,7,8

Strange that this seems to occur with one whole bank and not the other. More specifically, to the same bank. Maybe that bank has a slight design flaw or manufacturing flaw in the oil supply passageway to the pistons? Or perhaps the coolant doesn't flow as well as it should through that side for one reason or another? That's not the first time I've heard it as degradation of that whole bank together. Of course, these are rare enough that we're not really getting a good sample of the population. There probably just aren't enough failures to make any light of this speculation, but I figured I'd throw it out there.

[FarmerBob]

Anyone else reduce oil consumption by replacing pcv parts and pancake valve? (like post 29 above)

[timmmy]

HI everyone,

First post here, found this thread and figured I would chime in and try to add some info/get some info.

I have an Audi 4000Q race car roject that has the BHF V8 in it. The motor came form a wrecked 2005 S4 Cab, has 30K on it apparently. it sat in my dry garage for a few years before getting put into this car. When I picked up the motor 3 or 4 years ago, It had good comression and leakdown. Cold compression was around 155 +/-5.

Prior to initial startup in this project I rechecked it and it was good, down a little on cylinders 5&6 but not much.

I got the car running earlier in the summer and have run a good few events with it to start testing. Ever since I got the car going I have had problems with smoke on deceleration. I found that I had higher crancase pressure than I expected, but figured maybe these motors are just like that. After about 7 different configurations of breather setup I have it nailed, but have been confused as to why the stock setup seemed to allow so much oil into the inlet manifold.

In hindsight the breather issues make sense now.

I checked the cold compression prior to my last track event a few weeks ago and found cylinders 5&6 were down to about 125psi while the others were all around 150. This was the night before the event so I just went to the track anyway.

During the event I was way down on power, no more smoke than normal but the motor sounded a bit off too. I checked the compression hot and found the same two ylinders were now down at 90psi hot, and leakdown showed substantial ring blowby. Boroscope inspection shows that the piston lip right at the thin spot by the single valve cutout is missing about 1/2 to 1" of the edge of the crown, and a section of compression ring is missing also. Explains the blowby I guess!

My plan was always to boost this motor but I was hoing to run next season with teh stock motor to keep dialing in the ViPEC ecu and the chassis. It now look slike I wil be building a motor so will prep it for boost.

Q: Anyone found a good source for aftermarket rods / istons for these motors, or have good info on ring compatability with Alusil bores?

Q: Anyone have any feedback on relappping the bores? I had read that leather lapping may work?

I will likely use rods from 034 motorsport and have Mahle make pistons for me that will drop the compression a little in prep for some boost.

This is my first post here, so nice to meet you all. I included some links to my project thread and a video from the track last weekend. I will add info on what I find in the motor as I move forward.

Haydn (Timmmy)

1) Build thread on Motorgeek. (last page of 60) http://www.motorgeek.com/viewtopic.p...308&start=1375

2) Track video from NHMS last weekend (Motor running on 6 cyl effectivly) http://www.youtube.com/user/timmmy#p/a/u/0/-FuM4Fts2iI (loads more vids on my channel of this car)

[SquiddyB6S4]

Welcome Looking for motor build info would make a good thread, but you'll probably get poked for starting it here, since this thread is for motor failure discussion. But I'm sure if you start a thread about it (and show more racecar goodness) people will help out.

[SuperAvant]

Q: Anyone found a good source for aftermarket rods / istons for these motors, or have good info on ring compatability with Alusil bores?

Q: Anyone have any feedback on relappping the bores? I had read that leather lapping may work?

I will likely use rods from 034 motorsport and have Mahle make pistons for me that will drop the compression a little in prep for some boost.

This is my first post here, so nice to meet you all. I included some links to my project thread and a video from the track last weekend. I will add info on what I find in the motor as I move forward.

Haydn (Timmmy)

1) Build thread on Motorgeek. (last page of 60) http://www.motorgeek.com/viewtopic.p...308&start=1375

2) Track video from NHMS last weekend (Motor running on 6 cyl effectivly) http://www.youtube.com/user/timmmy#p/a/u/0/-FuM4Fts2iI (loads more vids on my channel of this car)

Check with JHM for the pistons and rods....