FAQ: Common Problems & Mechanical-Electrical Differences of the B6/B7 S4

[jaybquick@JHM]

Here are some mechanical facts and common problems we have come across (we will edit this post as we find time to add more info and as we come accross new discoveries. Feel free to contact us with any further help or parts with any of these items we mention.

Don't be extremely concerned with the common problems we share since ALL cars have their common problems and some NOT so common. This will hopefully help people fix their car quicker and at a lower cost with some of these facts hopefully serving as a tool.


Mechanical differences between B6/B7 S4

-Flywheels (A B6 flywheel only works with a B6 Pressure plate and the same with a B7, they bolt up to either motor though.)

-Clutch Pressure Plates (A B6 pp only works with a B6 flywheel and the same with a B7)

-Intake Manifolds (B6 S4 has a nice gray coating on top and the B7 S4 has a temperature resistant coating underneath where it is closest to the motor)

-Core support to motor clearance (the B7 S4 has about 1 to 2 inches more room there than the B6)

-Center Diff (The B6 S4 and the 05.5 B7 S4 only share the same center diff. The 06 and up B7 S4 and RS4 share the same center diff.)



Common trouble codes or Engine Electrical problems. and solutions

-Code = 18613 - Performance Malfunction in Cooling System
P2181 - 008 - Implausible Signal
Solution = If your coolant sensor checks out ok or has been replaced and your car is full of coolant this is MOST likely a sticky thermostat. (We sell these)

-MAF (Mass Airflow) sensor issues or MAF codes. These cars have Bosch MAFs which are notoriously known for the HIGHER than normal failure rate. We have seen this in the early B5 S4, B6/B7 S4, Jettas, A4s and many others. So MOST of the time if you have MAF codes or if you get weird long term fuel trim codes that are not due to a bad 02 sensor then it is highly likely your MAF is bad. (We sell the replacement electronic portion for a low cost on our site.)

-Missfires (shuttering or rough running engine) or flashing CEL. The CEL flashes to warn you that your car is missfiring and you WILL damage your catalytic converters if you don't fix the problem. Most of the time this is one or some of your coil packs going bad. The coil packs (8 per car) have been updated by Audi for the B6 and the B7 S4 several times and they are currently on revision Q. This indicates they are aware of this problem. (We sell the replacement OEM updated Q coil packs on our site.)



Engine mechanical failures and facts of interest
-We have talked to some customers that have had some kind of valve train and or timing chain issue with stock engines. We are not sure if it is commonly the rocker arms, the valve springs, keepers, tensioners, etc. As we get more specific details from them and or Audi we will share. We are not sure the percentage on how common this is.
-We have talked to some customers that have had oil consumption issues with stock engines that ended up being worn cylinder walls and needed an engine replacement (these cars have aluminum cylinder walls WITHOUT any kind of sleeve) We are not sure the percentage on how common this is.




I will keep this a living document and add more over time. Feel free to share more info in your posts with extra details about any of the items above or if you have an questions about something technical that you would like to see us answer please feel free to ask.

Thanks.

[ieatfishburitos]

Thanks Jason, I have to say I learn something most of the times I read your post..

[Storm33]

Thanks for the info, Jay. You guys rock the Audi world!

[Anthony]

Nice thread, J. You should definitely add this info to the Audizine Wiki as well, if it isn't there already.

[RudeBwoi]

perfect, hopefully more is added over time

[bsrpilot44]

Thanks for the heads up Jay...although I must admit after reading this thread, I'm a bit more paranoid over my car. hahahaha

-B

[jaybquick@JHM]

Thanks guys. I will add as I remember things I already forgot and after I learn something new with a customers car.

Also I wouldn't be too worried, ALL cars have their issues. At this point I am not sure about how common the major ones are yet.

[sakimano]

great post J

Center Diff (The B6 S4 and the 05.5 B7 S4 only share the same center diff. The 06 and up B7 S4 and RS4 share the same center diff.)

just wanted to add/ask:

the 2003-2005 MT6 and TIP S4 has a 50:50 torque split bias (TorSen T2)

the 2005.5 MT6 and TIP S4 has a 50:50 torque split bias (TorSen T2)

the 2006-2008 TIP S4 has a 50:50 torque split bias (TorSen T?)

the 2006-2008 MT6 S4 has a 60r:40f torque split bias (TorSen T?)

the 2005-2008 RS4 has a 60:40 torque split bias (TorSen T3)

does anyone know which (if any) of the later B7 S4 cars are TorSenT2 or TorsenT3?

[Veereihen6]

Can we add leaky valve cover gaskets to the common problems????

[3 bar]

You know what my main problem is. Motor mounts

[jaybquick@JHM]

great post J



just wanted to add/ask:

the 2003-2005 MT6 and TIP S4 has a 50:50 torque split bias (TorSen T2)

the 2005.5 MT6 and TIP S4 has a 50:50 torque split bias (TorSen T2)

the 2006-2008 TIP S4 has a 50:50 torque split bias (TorSen T?)

the 2006-2008 MT6 S4 has a 60r:40f torque split bias (TorSen T?)

the 2005-2008 RS4 has a 60:40 torque split bias (TorSen T3)

does anyone know which (if any) of the later B7 S4 cars are TorSenT2 or TorsenT3?

Well since the 06 and up S4 share the same part number for the diff as the RS4 they would be a T3 then. As for the Mechatronic transmissions (official name for the newer 6-speed auto) the OEM drawings don't give Part numbers for the center diffs so unless I tear a bunch apart to get the part numbers I couldn't tell ya.

I will add this soon.

Can we add leaky valve cover gaskets to the common problems????

Will do. However 70% of the cars on the road tend to have this issue. But these cars definitely act up more than some with leake VC gaskets.

You know what my main problem is. Motor mounts

Sure do. Post up the codes and then when you fix it we will have a solution and I can update the first post.

[SuperAvant]

Regarding oil consumption, what is considered high oil consumption to point worn cylinder walls as the culprit? It seems that all of these cars burn oil but I am wondering how much would warrant an engine replacement?

[Bpitz15]

Cold start issues should be up here. Just had my starter replaced under warranty because the car would not turn over when turning the key, i had to hold the key in the start position for 30 seconds and the car fired up. I have read on here that this is very common and could be a bad starter, clutch switch, or battery. Turns out mine was the starter.

[3 bar]

The code says upper motor mount solenoid short to plus apparently there is A TSB out on these for the a8s which involves dissconnecting the plug and adding a resistor to it

[jaybquick@JHM]

Regarding oil consumption, what is considered high oil consumption to point worn cylinder walls as the culprit? It seems that all of these cars burn oil but I am wondering how much would warrant an engine replacement?

Based on all the years of seeing different makes and models of cars with oil consumption issues and seeing what most companies say is normal, I would say if you are consuming more than 1 quart in 2000 miles. That seems a little high but these has been the standard in many TSBs for many companies, plus our cars hold 9.5 quarts of oil so 1 quart wouldn't put you at risk of running out.

Cold start issues should be up here. Just had my starter replaced under warranty because the car would not turn over when turning the key, i had to hold the key in the start position for 30 seconds and the car fired up. I have read on here that this is very common and could be a bad starter, clutch switch, or battery. Turns out mine was the starter.

Yes I have seen many speak of this and I think most are the starter. Hopefully more chime in to confirm this and I can update the thread. Thanks for sharing.

The code says upper motor mount solenoid short to plus apparently there is A TSB out on these for the a8s which involves dissconnecting the plug and adding a resistor to it

Now that we have an in house B6 S4 when I find the time to fuss with it I will try to figure out how to unplug the connector and keep the codes away.

[sakimano]

Well since the 06 and up S4 share the same part number for the diff as the RS4 they would be a T3 then. As for the Mechatronic transmissions (official name for the newer 6-speed auto) the OEM drawings don't give Part numbers for the center diffs so unless I tear a bunch apart to get the part numbers I couldn't tell ya.

nice...Mechatronic. NOT tiptronic. That's in play. I think they're T2 then.

suck it Mechatronic bitches!

[Beelzeebub]

How about suspension and brakes? does the B6 and B7 models share the same?

[Audi0s]

Auxillary radiators as well, I read about them alot, and mine started leaking at around 53k. Also some manufacturers consider a lot less mileage when dealing with consumption. BMW says 1 quart every 750 mi, imagine that!

[brit78]

Auxillary radiators as well, I read about them alot, and mine started leaking at around 53k. Also some manufacturers consider a lot less mileage when dealing with consumption. BMW says 1 quart every 750 mi, imagine that!

Speaking of coolant leaks, I and several others have had coolant leaks from the center of the block. 2 to 3 week fix job as the engine has to be torn apart. $5k plus job.

Also, window regulators go frequently. Just had one go last month.

Clicking/moaning from front suspension that a lot seem to get. Some say upper control arms, some say it is something else. My dealer said my UCAs and bushings were just fine, so who knows what the hell it is.

Fuel pump whine. Mine was just a fuel filter that needed to be replaced, others have had to replace the pump itself.

Phantom sunroof movements. Having that currently and know that others have had it too. I know there is a DIY on the subject around here somewhere.

I know that there are more I am forgetting.

[boravr6]

Phantom sunroof movements. Having that currently and know that others have had it too.

What do you mean phantom sunroof movements?


I dont know if this is a us / canada thing or just a difference in years but some B7 have a DRL switch next to the coming home switch. Mine doesnt.

[brit78]

[QUOTE=boravr6;3832786]What do you mean phantom sunroof movements?


Not sure if I am allowed to post links to AW on here, but here goes. Here is how to fix it at least. Titled "Sunroof Switch Repair (fixes random opening problem):"

http://www.audiworld.com/tech/elec.html

[Bpitz15]

Fuel pump whine. Mine was just a fuel filter that needed to be replaced, others have had to replace the pump itself.

whole pump replacement here...

[brit78]

whole pump replacement here...

Just out of curiosity, did the dealer suggest a whole pump replacement or did you figure that out on your own? Also, what kind of mileage did this occur at? Mine whine was at 48k miles on my '04. Just a month ago. Indie place replaced the filter only at my request due to what I've read on here and AW. Just curious to see what others experiences are about this. I could definitely see a dealership trying to replace the whole pump. Thanks.

[Bpitz15]

Just out of curiosity, did the dealer suggest a whole pump replacement or did you figure that out on your own? Also, what kind of mileage did this occur at? Mine whine was at 48k miles on my '04. Just a month ago. Indie place replaced the filter only at my request due to what I've read on here and AW. Just curious to see what others experiences are about this. I could definitely see a dealership trying to replace the whole pump. Thanks.

covered under warranty at around 41k. After doing my research on the problem, I mentioned the fuel pump and filter to them and they did the final diagnostics.

[SuperAvant]

Is there anyway to check for warn cylinder walls?

[Bpitz15]

Is there anyway to check for warn cylinder walls?

visual inspection by removing a head, or you could possibly get some information on the condition of your cylinder walls/rings by performing a compression test and also a leak down test.

[jaybquick@JHM]

First off thanks everyone for the suggestions and sharing your issues, as we get more accounts of stuff I will update my original post.

UPDATE about fuel filters: The B6s can have either a 3 line or 4 line fuel filter. So far we have seen the B7s having only a 3 line. We are trying to find out if any B7s have the 4 line one as well. Will update my first post when we get more feedback from people.

We know the B6 is hit and miss since we have reports of 05s that had a 3 port and our 05 had a 4 port.

How about suspension and brakes? does the B6 and B7 models share the same?

Most every part is the same, the only thing we have really notices so far is that the later B7s have those S4 logo caliper clips and the earlier B7s and B6s don't. Many people have been buying them from us.

Is there anyway to check for warn cylinder walls?

The first sign would usually be oil consumption, smoking or power loss. Oil consumption or smoking could also be valve guides or seals (less common however).

Personally if I was suspecting worn cylinder walls I would do a compression check. Then I would do a second compression check after squirting a little oil in the cylinders. If the pressures went up substantially this would indicate the rings and cylinders were sealing properly and the oil made it seal right (old trick). This would rule out other things. Going a step further you can do a leakdown check and if it is in the 15% plus range and you don't hear or see air in the exhaust, intake or coolant and hear plenty from the crank case then they would be a more precise way.

Ultimately after being certain with those tests a teardown would be the 100% way to know for sure.

What are your symptoms?

[Leeber]

How about dipped headlights, from bad modules and such not from burned out bulbs. My b7 has this problem and I've read other posts that people have this problem alot.

[eneq]

Second on the window regulators, had them replaced on the right side at ~31k and they have occasionally misbehaved after that as well but not frequent enough to warrant a dealership visit (was covered by warranty btw).

Overall the warranty has covered everything except one thing. The carbon fiber trim around the gearshift and ashtray has started to become undone along the edges causing them to warp slightly. This is not a mechanical or electric problem but I mention it here because it kinda pissed me off that it wasnt covered by the warranty. Actually the dealer told me that it was explicitly excluded from warranty since 2005 (probably such a frequent issue that they lost too much money on it).

Fixing it around the gearshift is kinda easy tho but getting access to the ashtray is a whole different matter.

/Q

[homeychan]

AC failure seems to be a common problem in these cars too, I have seen a lot on the forum and mine has this problem.

[abe]

The carbon fiber trim around the gearshift and ashtray has started to become undone along the edges causing them to warp slightly.

Do you park your car in direct sunlight much? I'm just wondering if it can be prevented by keeping as much heat out of the car as possible.

[jdmoorman]

I would ask the dealer to show me the exclusion in print.

[mr. d]

How about control arm bushings and front wheel bearings.

[whartung]

How about control arm bushings and front wheel bearings.

I just had my front control arm bushings replaced by the dealer this wednesday under warranty because mine were cracked and worn. 43,500 miles on my 05.5

[Silver B6 S4]

I just had my front control arm bushings replaced by the dealer this wednesday under warranty because mine were cracked and worn. 43,500 miles on my 05.5

Had my upper links replaced 3 weeks ago. 37,000 miles on my 04.

[iconoclast]

Mechanical differences between B6/B7 S4

-Flywheels (A B6 flywheel only works with a B6 Pressure plate and the same with a B7, they bolt up to either motor though.)

-Clutch Pressure Plates (A B6 pp only works with a B6 flywheel and the same with a B7)

what exactly is different about either? is it anything in terms of increased performance or lighter etc or just the way the mate up?

[S4Blitz]

The B7 flywheel was updated to address the high failure rate of the B6 flywheel.

[jaybquick@JHM]

what exactly is different about either? is it anything in terms of increased performance or lighter etc or just the way the mate up?

The B7 flywheel was updated to address the high failure rate of the B6 flywheel.

There is a step height difference and the B7 has a better clamp load. Of course I won't disclose the amount. We paid good money to have both pressure plates tested and the RS4 plate tested. And bought both flywheels for measurements and weights. We have been playing with these flywheels and pressure plates and testing friction materials at the track and with launches since December 08. Here is a video of an example of some of our testing. http://jhmtuning.com/videos/B6S4/JHM...d_burnouts.wmv

We will officially release our lightweight flywheel and clutch kits soon. We have them in stock, just haven't put them on the site until we get all our sources up to speed for the parts and can handle the volume.

We based all our setups of the B7 flywheel. And yes the B6 flywheels do tend to have the dual mass fail and sometimes hitting the trans bellhousing and cracking it. The B7 flywheel weighs .5 lbs more as well but is similar in design. It is yet to be seen if they will experience the same problem. This kind of sucks since we wanted to modify and resurface the B6 flywheels but won't now that we have seen several of these failures. With the B5 cars, their flywheels never failed even with 600 hp cars.

[evil_O]

Being gone for quite a while from the boards... and now reading ad nauseam, I am starting to wonder if I should cancel my back ordered exhaust and go with a company like JHM. I am thrilled with all the information they are providing for our cars... not to mention awesome vids like the one above!!!

Besides, JHM's CB is 2.5 vs 2.25... leaving me room for growth right? I mean right????

[jaybquick@JHM]

Being gone for quite a while from the boards... and now reading ad nauseam, I am starting to wonder if I should cancel my back ordered exhaust and go with a company like JHM. I am thrilled with all the information they are providing for our cars... not to mention awesome vids like the one above!!!

Besides, JHM's CB is 2.5 vs 2.25... leaving me room for growth right? I mean right????

You are correct, the 2.5" will leave you room for growth. Also with my own personal testing on SEVERAL cars we have NEVER seen an acceleration loss at ANY rpm with the 2.5" setup we sell on the B6/B7 S4.

We do RPM/Sec acceleration tests in identical conditions on the same road to see what the car does in REAL situations. And we ALWAYS see gains in ALL the RPM. So there is NO debate. The 2.5" will NOT hurt accelaration. Isn't acceleration what we want??? Ultimately you want your car to out accelerate the competition. Numbers on a dyno don't count when the other car is showing you their tailights. Peak numbers and theory NEVER make your car faster, a larger power band throughout the range does. This is how we test ALL our products before we sell them. If it doesn't accelerate better, we don't sell it, that simple.