New ownership deliberation: B8 Avant Prestige with DSG & ALL options

[JLAllroad]

When I inspected the car before buying I noted the front tires were pretty worn. What do you think? This picture is ~700 miles after purchase.

Attachment 328592

Beyond that, I've started working with Motoza Performance to get this thing on Stage 1 ECU & TCU (ZF8) tunes. First I want to boost leak test the car to ensure it's good there. Also want to hear their recommendation on spark plugs.

And this is how it looks under the engine beauty cover. Gotta love previous owners!

Attachment 328593

Also the PCV is a white top which I understand wasn't factory for this car, but it had stage 1 oil consumption work done a while ago... so makes sense it would have white top now. Except this white top appears to be aftermarket?

Attachment 328594

You would want to verify that you’re running software version 2 as updated software and front crank seal were required to use the updated PCV given it operates at nearly 3xs the vacuum of the original black cap. Once that is determined I would suggest replacing with an OE (Hengst) of the proper revision.


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[MetalMan]

You would want to verify that you’re running software version 2 as updated software and front crank seal were required to use the updated PCV given it operates at nearly 3xs the vacuum of the original black cap. Once that is determined I would suggest replacing with an OE (Hengst) of the proper revision.

Below is a snippet from the oil consumption warranty work. It doesn't show software version as far as I can tell, but it explicitly lists the technical bulletin 2027731/5 and the seal/PCV/screw parts correctly, so I'd assume the correct software version was also installed.

My pre-purchase VCDS log shows Part No SW: 8K2 907 115 AG, then the next line shows Component: 2.0l R4/4V TF H19 0002. Wondering if the last number is the software version. Regardless, this work shows up in 2015 which is later than the issuance of Rev 5 of the technical bulletin.

Perhaps also relevant, from the 700 miles I've added so far the MMI oil level shows full (as it did pre-purchase). Seems to me if it were consuming oil that wouldn't be the case...

oil-consumption-work.jpg

[bb-tt]

part of stage 1 is sw update

[MetalMan]

Been a little while, have some updates:

• Car is fully tuned on Motoza Stage 1 ECU + TCU, I was a beta tester for the B8 A4 platform for them.
• The oil level did drop maybe 1/4 of the gauge after ~2500mi. Not too bad.
• Did my first oil change a couple weeks ago, which was accelerated by "Oil Level Sensor Defective" warning on the dash. Turns out that an oil level sensor wire was cut (chewed??) through! I actually bought a new Hella oil level sensor, glad I didn't need to replace it, though. Also added an ECS magnetic oil drain plug while in there.
• Swapped to an 8V facelift flat-bottom steering wheel (FBSW) which is the same as B9. Used a signal decoder, and acquired and modified a B9 airbag (there's no airbag fault). Looks SO MUCH BETTER. This steering wheel was previously in my prior 2015 A3 and I loved it there. I also have on-hand (but yet to install) more basic buttons from a UK B9, since the B8 can't use half the buttons currently on this steering wheel. This new button set more closely matches the stock B8 buttons.
• Planning on bigger brakes: Front: 4M Q7 calipers (no spacer) with C7 A6 rotors, B7 RS4 Centric brake lines; Rear: B8.0 S4/S5 rear brakes. Hopefully the fronts will work out as I'm planning, but if not I'll get B9 S4/S5 front calipers and add a spacer to them.

steer-wheel.jpg

[bb-tt]

Been a little while, have some updates:
[*]Planning on bigger brakes: Front: 4M Q7 calipers (no spacer) with C7 A6 rotors, B7 RS4 Centric brake lines; Rear: B8.0 S4/S5 rear brakes. Hopefully the fronts will work out as I'm planning, but if not I'll get B9 S4/S5 front calipers and add a spacer to them.[/LIST]

Thats allot of extra weight A6 rotor alone is ~22lbs cant imagine how much the q7 caliper weighs. Also the goodridge RS5 stainless lines were fairly cheap ~$100 (all 4 lines part#30020)

[MetalMan]

Thats allot of extra weight A6 rotor alone is ~22lbs cant imagine how much the q7 caliper weighs. Also the goodridge RS5 stainless lines were fairly cheap ~$100 (all 4 lines part#30020)

I don't have the 4M Q7 calipers yet, but them being aluminum I think may help negate some of the extra weight vs size relative to the stock calipers. Of course rotors will add extra mass, can't get around that at my budget.

SS lines are on the way, I spent $107 with tax for front and rear, which is about $99 before tax.

[SNice]

The 4M calipers were 13.4lbs (each) w/o pads.

You also may want to check your specs - I believe the A6 rotors are 34mm thickness. The 4M caliper is expecting a rotor with 36mm thickness.


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[bb-tt]

where did u get the linbus adapter for the steering wheel?

[MetalMan]

The 4M calipers were 13.4lbs (each) w/o pads.

You also may want to check your specs - I believe the A6 rotors are 34mm thickness. The 4M caliper is expecting a rotor with 36mm thickness.

Good call! I was conversing with a guy on FB about this brake upgrade, he was helping me steer toward the 4M Q7 option instead of B9 S4/S5 since 4M Q7 shouldn't need a spacer to fit 356mm diameter rotors (and they're cheaper). But you bring up a great point... B9 S4/S5 calipers are a little smaller, and expect 34mm rotors like C7 A6 356mm

So I guess I'll go 380mm SQ5 style rotors which are 36mm thick? LOL
I laid out some of those rotor options here: https://www.audizine.com/forum/showt...7#post15104337


In other news, the 4M Q7 calipers I ordered off ebay are supposed to arrive today. I honestly don't know what to expect on their appearance... the ebay listings only showed the cars they came from since the calipers weren't pulled yet. In my order notes I asked them to send pictures and verify with me prior to shipping but they seemed to have ignored that request...

where did u get the linbus adapter for the steering wheel?

Aliexpress: https://www.aliexpress.us/item/3256806338378808.html Don't know if it's necessary but I ordered the "For A4" option.

And actually last night I just swapped over the "basic B9" buttons to my steering wheel. Thankfully they work, but now my paddle shifters aren't working despite being plugged in...

[MetalMan]

Got one side of the 4M Q7 caliper + 380mm SQ5 rotor (Dynamic Friction 900-73062) mocked up. Just cleaned the caliper to get it ready for paint, so this isn't final install. And did the necessary grinding to the caliper bracket and knuckle. As you can see the fitment is PERFECT with the 9/16" tall caliper bracket spacers I chose. And plenty of wheel clearance with my stock 19" wheels! (no wheel spacers)

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[shreddykrueger]

Great call going this route instead of Macan calipers. The caliper & rotor fill out the wheel perfectly and the brake-feel is so much better

[MetalMan]

Took an extra 3 months but I did finalize and install the 4M Q7 front calipers with Dynamic Friction coated/high-carbon SQ5 rotors. Also designed and had made some CNC anodized aluminum spacers that bolt to the 4M caliper brackets to space out the calipers.
In the rear I went with C7 S6 356mm brakes (same line of Dynamic Friction rotors as the front). The parking brake motors work perfectly in the B8.0 including cycling with VCDS.

And of course new SS brake lines and a full brake fluid job with Bosch ESI6-32N fluid. Went through more than 5 quarts, used Motive power bleeder up to 30psi, plus did some ABS pump cycling via VCDS. The brakes are feeling good!


Also did a full drivetrain fluid change... ZF8 trans fluid/filter, center diff got Motul Gear 300 LS (its P/N 105778 cross-references to Audi's "unicorn piss" fluid), front and rear diffs got Fuchs Titan Sintopoid 75W-90.


Maybe 6 months ago the car was under a tree (eucalyptus ??) that dropped stuff on the car, and with my limited free time I didn't wash it for a little while. Well, between condensation and temperature cycling those droppings stained and etched the clear coat . Was able to get the staining out without too much difficulty, but it took a decent amount of buffing with rubbing compound to make the roof look adequate.

The hood had old PPF on it that was damaged from those droppings, and it took a lot of time and effort to remove the PPF. Afterwards I polished the hood and it looked great! But I didn't apply wax or anything to the hood, and didn't wash the car for a while... the car is mostly parked in the garage, but some bird droppings and whatnot etched the hood's clearcoat . So had to buff with rubbing compound and polish again, and now you wouldn't even know there was any etching on the hood. This time I'm applying Turtle Wax's hybrid "ceramic spray coating" to the entire car, doing a 2nd coat tonight.


Lastly, on the steering wheel buttons: the paddle shifters stopped working with the "basic B9" buttons because that button set doesn't support paddle shifters (the connectors/wiring harness has less pins). I'm wondering if I could use the "basic B9" button faces over top of the regular buttons.


4M Q7 caliper bracket mod for B8.jpg
front Q7+SQ5 brakes.jpg
rear C7 S6 brakes.jpg

[Smac770]

The basic buttons can support paddles. You must have the wrong set.

8W0 951 523 is no paddle support basic buttons for trapezoid airbag
8W0 951 523 A is with paddle support basic buttons for trapezoid airbag
8W0 951 523 C is no paddle support basic buttons for round airbag
8W0 951 523 D is with paddle support basic buttons for round airbag

The 9-wire basic buttons harness was 8W0 971 589 C, now 4M0 971 589 C.
This is different from the 11-wire advanced buttons harness 4M0 971 589 B.

[MetalMan]

The basic buttons can support paddles. You must have the wrong set.

8W0 951 523 is no paddle support basic buttons for trapezoid airbag
8W0 951 523 A is with paddle support basic buttons for trapezoid airbag
8W0 951 523 C is no paddle support basic buttons for round airbag
8W0 951 523 D is with paddle support basic buttons for round airbag

The 9-wire basic buttons harness was 8W0 971 589 C, now 4M0 971 589 C.
This is different from the 11-wire advanced buttons harness 4M0 971 589 B.

Great info, thanks!
Base on this, 8W0 951 523 D would be correct, except they don't seem to be for sale anywhere just based on P/N. Perhaps I could locate them for sale (used) from a European source. My current non-paddle basic buttons (8W0 951 523 C, I guess) came from the UK.

At this point I'm $85 deep in the non-paddle basic buttons. If I can swap button faces that's $0 more

Alternatively, ModHub sells basic buttons that I'm guessing support paddles, and they claim plug-and-play for the B8; i.e. no Linbus adapter. Looks like a nice offering but $166 plus $35 shipping from Singapore is kinda steep. https://www.modhub.com.sg/collection...tons-for-a4-b8

[Smac770]

Yeah, you're not going to find the basic buttons in the NAR market; they weren't used here. You could hit up Alex at europrice.us and see if he has any source of them. The ModHub price isn't bad at all, considering they incorporate the LIN translator so you wouldn't have to separately source that. But you already have that and $85 in buttons that aren't the correct ones. So you'd have to look to see what you can get back out of those first. And he has a pic of a paddle wheel there, but you'd want to confirm they are D and not C units.

[Chillaxin]

Picked it up today. Also took it in for smog test which it passed no problem.

It's been really windy and pollen is everywhere, and the car was dirty to begin with. But from afar you can't tell!

Drove it a decent amount already due to timing and location of picking it up and my work schedule and it felt pretty solid. I feel like if it has a low oil pressure situation it would've shown up through the driving I did.

It caught me by surprise that although these cars have Bluetooth phone connection, they lack BT audio streaming!!!!!! Man that sucked to learn the hard way, lol. Therefore I've already dropped $164 @ AliExpress for the "Road Top Wireless Carplay Audio Interface". There's a similar module on my 2015 A3 that's worked well enough.

Also going to need a phone mount sooner than later... plopped $16 on a cheapo Aliexpress center vent one, if that ends up sucking too much I'll consider the $55 Rennline option.

Lastly, I haven't looked through the user manual yet, but I haven't figured out how to switch around the menu that shows vehicle data on the instrument cluster. i.e. right now it shows speed in large font and instantaneous MPG in small font. I'm assuming there's a way to toggle through that menu so I can get it to show average MPG for example. The way I flip through this menu on my A3 doesn't seem to work on this A4 (it just toggles through the media menu).

Attachment 326319

You can upgrade to the b8.5 mmi+ and get Bluetooth audio streaming. That requires component protection removal at the dealer or a vag can pro purchase. There is a thread about it on the zine somewhere.

[MetalMan]

You can upgrade to the b8.5 mmi+ and get Bluetooth audio streaming. That requires component protection removal at the dealer or a vag can pro purchase. There is a thread about it on the zine somewhere.

I appreciate the info. BT streaming is only part of it for me, having Android Auto is even better (you can stream over AA). So for $164 I got an integrated device that didn't require any programming / ODIS work, and grants me wireless AA which the B8.5 MMI+ wouldn't.

[MetalMan]

Setting myself for some upcoming maintenance work:

• Water pump / thermostat... currently car is persistently throwing P2181 which is a thermostat fault. Figure I might as well do water pump "while I'm in there".
  
  • Just trying to figure out which pump to buy... thinking Pierburg 7.07152.08.0
• With doing water pump, thinking I could just take off intake manifold and do a carbon clean (I did it on EA888 2.0T in 8V A3, so have all the equipment).
• If intake manifold comes off, maybe replace injectors???
• Boost leak test - I've done this on multiple past Audis (1.8T x 3, 2.7T) but not sure the right approach for this 2.0T.
• Fuel filter - probably hasn't ever been changed, and with 93k miles a new one may improve MPG
• Wondering about replacing primary O2 sensor...

[MetalMan]

Contemplating replacing the coolant flange on the back of the head while coolant is drained for water pump. Has anyone tried one of the cast aluminum versions? Like this: https://www.amazon.com/gp/product/B0C5R7D1Y8/

[StuckAntichris]

The metal flange is fine but the weak link is still the gasket/o-ring. I havent seen many of the plastic ones fail since there isnt much stress on those hoses.

[MetalMan]

Thanks for the info. I had come across a number of posts where people mentioned the stock plastic one "disintegrated". Granted that's probably happening after more than 10 years, and given my track record it's unlikely I'd own this car for anywhere near that long...

[Smac770]

It depends on if you look at it wrong. Usually it breaks when people need to mess with heater core hose or the reservoir overflow hose that connect to it. Mine holding on best it can after 275k miles:

my A4 coolant flange and heater supply hose.jpg

A new one is dirt cheap, so replace it if it's got any substantial age on it while the coolant is out. But you can see, you might consider the heater hose as well depending on its condition.

[Oliver@Motoza]

Just seeing this thread now! We are active on here, and happy to answer any questions we can regarding the tuning options.

Been a little while, have some updates:

• Car is fully tuned on Motoza Stage 1 ECU + TCU, I was a beta tester for the B8 A4 platform for them.
• The oil level did drop maybe 1/4 of the gauge after ~2500mi. Not too bad.
• Did my first oil change a couple weeks ago, which was accelerated by "Oil Level Sensor Defective" warning on the dash. Turns out that an oil level sensor wire was cut (chewed??) through! I actually bought a new Hella oil level sensor, glad I didn't need to replace it, though. Also added an ECS magnetic oil drain plug while in there.
• Swapped to an 8V facelift flat-bottom steering wheel (FBSW) which is the same as B9. Used a signal decoder, and acquired and modified a B9 airbag (there's no airbag fault). Looks SO MUCH BETTER. This steering wheel was previously in my prior 2015 A3 and I loved it there. I also have on-hand (but yet to install) more basic buttons from a UK B9, since the B8 can't use half the buttons currently on this steering wheel. This new button set more closely matches the stock B8 buttons.
• Planning on bigger brakes: Front: 4M Q7 calipers (no spacer) with C7 A6 rotors, B7 RS4 Centric brake lines; Rear: B8.0 S4/S5 rear brakes. Hopefully the fronts will work out as I'm planning, but if not I'll get B9 S4/S5 front calipers and add a spacer to them.

steer-wheel.jpg

[S-Liner]

Mine has been fine @[emoji[emoji6]][emoji[emoji6][emoji6]]Kmiles. However, the hose itself failed. The factory crimp band gave out and shot off. Luckily was near an autozone and fixed it with a banjo clamp and a coolant top off.

Suppose I’ll give a once over on all the hoses


Sent from my iPhone using Audizine

[avantbunnie]

If you want to do a EU/ROW taillight mod, let me know!!

[MetalMan]

... I'm wondering if I could use the "basic B9" button faces over top of the regular buttons.

At this point I'm $85 deep in the non-paddle basic buttons. If I can swap button faces that's $0 more

Had both button sets disassembled, and the basic button faces won't work on top of the standard (with paddle support) button circuit boards. The back housing portion is identical, though.

Setting myself for some upcoming maintenance work:

• Water pump / thermostat... currently car is persistently throwing P2181 which is a thermostat fault. Figure I might as well do water pump "while I'm in there".
  
  • Just trying to figure out which pump to buy... thinking
• With doing water pump, thinking I could just take off intake manifold and do a carbon clean (I did it on EA888 2.0T in 8V A3, so have all the equipment).
• If intake manifold comes off, maybe replace injectors???
• Boost leak test - I've done this on multiple past Audis (1.8T x 3, 2.7T) but not sure the right approach for this 2.0T.
• Fuel filter - probably hasn't ever been changed, and with 93k miles a new one may improve MPG
• Wondering about replacing primary O2 sensor...

Got a bunch of stuff on order:

• Pierburg 7.07152.08.0 water pump / thermostat , Continental 06H121605E belt (unsure about actually replacing it, though)
• aluminum water pump union - URO 06H121131C
• the aluminum coolant flange "Sprwinautummer 06H121132H" from Amazon
• fuel injectors Bosch 62855, from Rock Auto so shouldn't be knock-offs... also bought Elring installation kit 06J998907D
• throttle body & intake manifold gaskets, both Elring (also planning to clean throttle body)
• fuel filter - Bosch 8K0201511A

In other news, I read up a bunch on the Canyon Run CR-15 strut tower brace, and it sounds like a beneficial upgrade. Because I'm cheap and capable, I bought from Online Metals a square tube 1" x 1/8" x 44" 6061-T6 for $18 that I will fashion into a CR-15 equivalent for much less $$$. My initial measurements make it look like ~38.5" length is good but I haven't started on the project yet.
Good info on DIY here: https://www.audi-sport.net/xf/thread...2#post-2716681

If you want to do a EU/ROW taillight mod, let me know!!

Like many here, I can't help myself when it comes to mods. Always in for more info!

[MetalMan]

In other news, I read up a bunch on the Canyon Run CR-15 strut tower brace, and it sounds like a beneficial upgrade. Because I'm cheap and capable, I bought from Online Metals a square tube 1" x 1/8" x 44" 6061-T6 for $18 that I will fashion into a CR-15 equivalent for much less $$$. My initial measurements make it look like ~38.5" length is good but I haven't started on the project yet.
Good info on DIY here: https://www.audi-sport.net/xf/thread...2#post-2716681

And now it's complete / installed. No doubt it's a lot less pretty than the CR-15, but all-in I literally spent $34 and $10 of that was a step drill bit... CR-15 is $135 right now so for a few hours I saved $100. As the Audi-Sport link mentions, I used the factory stamped steel piece as a template to get me started, followed by a lot of test fitting and grinding.

PXL_20250221_053958450-1.jpg
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[MetalMan]

Moving along with more budget upgrade ideas...
Came across the 3.0 TDI larger intercooler 'upgrade' and became very intrigued. Dove into lots of past posts about it, as well as the Treadstone TR8 option.
I'm no novice when it comes to intercoolers, I had a TR18T on my old B5 A4. But that had a bigger turbo, whereas this B8 is only stage 1.
Anyways, TR8 plus hoses/couplings is pushing ~$350+, whereas a Behr brand 3.0 TDI IC is $143 - 5% + $12 shipping on Rock Auto (<$148).


EDIT: Bought the Behr 3.0 TDI IC from Rock Auto. Should be fine for my usage on stage 1, and I gotta keep the budget in check.

[MetalMan]

With the upcoming work I was wondering about going into full service position and doing a timing job (while front bumper is off for IC replacement and coolant is drained for water pump).
So I finally measured "timing chain stretch"; VCDS reports -2.46° on IDE00182 "Camshaft adaptation intake bank 1 : phase position" after blipping the throttle. Seems really good for 94,261 miles! Needless to say that job can be postponed...

EDIT: I'll need to check the old service records; I saw a few forum posts suggesting the timing job is sometimes completed with the piston ring job, and since mine doesn't consume much oil it might have underwent the piston ring job... and therefore maybe timing chain as well.

[MetalMan]

Went ahead and replaced fuel filter last night. Really not too bad of a job, probably took me ~45 minutes total for ALL of it including cleanup (which was minimal because of pulling fuel pump fuse to drain system pressure, and had gas cap off). Rented the "fuel pump tool" from Autozone which was a big help. Of course the seat bench mounting clips (expectantly) exploded, so although only 2 are needed I ordered 8 from GenuineAudiParts.com for <$5 ! (free shipping).

EDIT: I have no idea the age of the old fuel filter, however I do feel like the car's throttle response is "snappier". This morning was my first time really driving the car in maybe 10 days, and the "snappiness" surprised me a bit.

[MetalMan]

Anyone have an opinion on ebay RS-style grilles? Something like this one: https://www.ebay.com/itm/387630826689 It's $110 right now with the current coupon and free shipping.

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[Matt Devo]

Anyone have an opinion on ebay RS-style grilles? Something like this one: https://www.ebay.com/itm/387630826689 It's $110 right now with the current coupon and free shipping.

personally, I think the ones without the rings holder integrated into the mesh look meh, and that the split lower section (with optional Quattro badge) looks better than the full mesh

[MetalMan]

personally, I think the ones without the rings holder integrated into the mesh look meh, and that the split lower section (with optional Quattro badge) looks better than the full mesh

Thanks for the feedback. I agree that it'll look better with rings/holder. However, I'd opt for the full mesh version; to me that option will look better if/when I add a front plate (which wouldn't necessarily be my choice...).

[MetalMan]

My deliberations led me to wanting the RS style grille with chrome trim and chrome rings. Also found out there is a RS style fog light grille for S-Line with black or chrome trim.

So I plopped a small chunk of change on these:

• $65 shipped https://www.aliexpress.us/item/3256806677707281.html Their chat "support" thinks it will be the 1st picture below but they were useless on the rings color (first told me "chrome black", then "black"). Hoping it will be chrome trim and chrome rings, though... Regardless, this one was stupid cheap.
• $37 shipped https://www.aliexpress.us/item/3256804085458964.html Selected chrome trim option (2nd picture).

Audi-grille.png

fog-grilles.png

[MetalMan]

Been a little busy after getting started tearing the car down earlier this week:

• removed intake, was surprisingly difficult to pull/wiggle out. I guess the injectors were really stuck in there.
• drained coolant, changed out water pump and installed URO aluminum oil cooler union
• replaced water pump belt with new pulley screw. Spent $15 on this "torque adapter" 12mm wrench and modified it to fit (first pic below). Have the core support in service position to access the 24mm crank pulley bolt.
• working on replacing O-rings in radiator hose connectors, same for heater core hose connector O-rings, and the hard pipe that attaches to WP
• last night tried to get the aluminum coolant flange installed... yeah that failed:
  
  • where the solenoid attaches, the little arms that should be springy were too stiff so I shaved them down, then they were too brittle and broke. Also it was too thick anyways, but fit okay once I shaved the thickness.
  • the nipple where the heater core hose connector attaches is smaller than stock flange by 0.022" (0.56mm), so obviously wouldn't seal as well. I was planning to get around that by using a thicker 20x4mm O-ring (bought some) compared to the stock 22x3.5mm.
  • but now the deal breaker, and related to pics below: the damn thing doesn't fit in the cylinder head! I should've checked this first before wasting so much time/money trying to make the rest of it work.

Working on the best option for a new Genuine coolant flange. Would've been nice to know sooner about the aluminum one (which is also too late to return).

Thinking this weekend to start working on injector replacement, maybe carbon clean.

Lastly, I found a SUPER cheap aluminum transmission mount insert (China special) located nearby, $9 shipped from ebay!

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[MetalMan]

Was able to get the local Audi dealer to price-match the coolant flange. And of course it went right on, perfect fit.
All of the above-mentioned cooling system O-rings got replaced. The one pictured below is from the plastic hard pipe where it attaches to the water pump. Left is the old, right is new. Crazy how flattened the old one is...
Planning to pressurize the cooling system up to ~15psi or wherever the cap relieves pressure to check for leaks.

Also started screwing around with injectors. Old ones were all pretty well stuck in the fuel rail. And new Bosch ones (from Rock Auto) are tight going into the cylinder head. I think the correct procedure is to install them in the head first, then install the rail over them. Have to figure that one out since there's little access to injector connectors this way.

PXL_20250328_221155082~2.jpg

[MetalMan]

At this point all the things on the engine side are back together. Some comments:

• Injectors were tight going back into the cylinder head. One post I read suggested to push them in initially, let them rest in place, and push them further (and repeat if needed). This seemed to work well enough. Should also mentioned I tried cleaning the injector bores with carb cleaner soaked Q-tips.
• It was indeed tricky plugging in the injectors while installing the intake manifold. But it's doable! It helped to unclip the wire harness a little from the fuel rail near the oil filter (to get extra length).
• Completed carbon cleaning. I used a custom 3D-printed walnut blasting adapter I designed for my old 2015 A3 2.0T, but it fit/worked perfectly on the B8 as well. From the A3 I had leftover fine grit walnut shell media that went to good use here.
  
  • The 2 middle cylinders in particular, had carbon that was hardened/baked on to the valve heads. No amount of scraping (with metal tools) and walnut blasting could free it up, even soaking in carb cleaner for 1+ hour (followed by more blasting) did nothing. It seems like a decently thin coating, at least, so I'll let it be. If time was on my side I'd try longer-term soaking with something like B12 (of course with only up to 3 cylinders at a time).

Looking forward to getting the car back together, but first need to pressure test the cooling system... for which I have an Amazon China-special kit en-route. After success there, the car will get coolant.
Then it'll be time to install the 3.0 TDI intercooler and perform a boost leak test (with this PCV block off).

In other news, I'm still waiting on the RS style grille, and the fog light grilles came in (and they look pretty good).

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Middle cylinder valves now look like this:

PXL_20250404_050925853~2.jpg


And outer cylinder valves now look like this:

PXL_20250404_050955623~2.jpg

[MetalMan]

Cooling system pressure test tool came in today. Pretty quickly after setting it up I heard a dreaded hissing noise. And this is where it bit me that I had already assembled the intake manifold back onto the engine... fortunately I'm quicker at it now and had it back off in no time.

Easy pressure test (intake mani removed):

PXL_20250404_044259812~2.jpg


Located the leak pretty quickly:

PXL_20250404_044245797~2.jpg


That's an O-ring I just replaced!!! Looking closer, and this is something I noticed earlier, the newest version Pierburg (aluminum) water pump lacks a lead-in chamfer/taper to help the hard pipe's O-ring seat inside it. This meant I had a heck of a time getting the hard pipe in, apparently because I was ripping & tearing the O-ring on its way in:

PXL_20250404_044314407~2.jpg

PXL_20250404_045121412~2.jpg


For reference, the previous plastic water pump has the proper lead-in chamfer/taper:

PXL_20250404_044738909~2.jpg


So now what??? I could get another new Audi O-ring (FYI I measured the size to be about 3mm thick X 21mm ID) but there's a high chance it tears again.
2 posts back I showed the new vs old O-ring, where the old O-ring is decently flattened.
For now I'm opting to just re-use the old one because in its flattened state I can actually seat the hard pipe without damaging the O-ring...

And after an hour @ 15psi, the cooling system pressure test pump shows ~0.25psi drop; I can't at all hear any hissing. Air will always leak more readily than liquids so I'm going to call it "good enough".

[MetalMan]

Over the weekend I completed the boost leak test @ 15+psi through the turbo inlet pipe/hose. Fortunately no surprises there, I couldn't hear any leaks other than air escaping from the open oil cap as expected. Then started the engine which went well once I remembered to reinstall the fuel pump fuse.

The last couple nights this week I tackled some scope creep items: PCV (old one was no name Vaico or Uro brand, new is Hengst with the Audi markings), and primary + secondary O2 sensors. And of course cleared codes to reset fuel trims and whatnot.

Old PCV followed by new PCV:

old PCV.jpg
new PCV.jpg


Old oxygen sensors may have been original (94k miles), they were Audi branded, and new are Bosch 17178 and 16002 :

primary O2s.jpg
secondary O2s.jpg


Still waiting on the RS style grille. It's hard to wait! Ordered March 21, and last shipping progress update was 8 days ago (update prior to that took 7 days). Since then also from a Chinese Aliexpress seller I ordered some Audi rings puddle lights on 4/3 and got them yesterday 4/8.


Lastly, from a UK ebay seller I got a new B9 steering wheel... 8W0419091F , you'll notice it has basic buttons and paddle shifters! I probably won't keep the red anodized paddle extensions in case anyone is interested... already scavenged the media buttons and the paddle extensions, and chucked the wheel. Gotta find the time to swap in these media buttons.

B9-wheel.jpg

[MetalMan]

Got the car back together last night (mostly bumper re-installation), and ran it for 1-2 minutes. Also installed the super cheap China-special transmission mount insert (which fit great).

Commuted to work today for my first official drive after all that work (cleaned: carbon from valves & intake ports, throttle body ; new parts: injectors, PCV, oxygen sensors, water pump/thermostat, 3.0 TDI intercooler).
Outcomes:

• I noticed a little extra vibration from the trans mount insert, not too bad. I'll run it for now.
• My coolant gauge went to the middle tick! Previously there was occasionally a CEL for P2181 "Performance Malfunction in Cooling System", and coolant gauge needle sat a bit below halfway.
• Gas mileage was notably improved. By the time I parked, car reported 31.7 mpg; during my morning commute for similar driving style I would previously have expected ~28.7 mpg. So that's +10% improvement... granted the ECU is still adjusting after clearing fault codes/fuel trims, but I'd expect gas mileage to only improve as it adjusts.
• Didn't go deeper into the throttle to check shift feel with the mount insert or see if it pulls harder with the bigger intercooler, yet.