AUDI S4 B8/B8.5 Life Beyond 100K Miles / 160K KM

[DavH]

Hello everyone,

I've been doing readings on different sites for about two years now.
The B8/B8.5 platforms seem to be excellent platforms when taking care of while still retaining some weaknesses.
I would therefore like to put together a guide that can help inform all possible owners regarding future maintenance and repairs on a B8/B8.5 with 100K miles / 160k km.

Second owner, have the car since 2016-03-08 at 73896km.
02/23/2018 - 111,937km - Mechatronic repair kit: $3,040.41
12/15/2021 - 166,969km - Gas pump module: $515
02/12/2022 - 174,707km - Cleaning of secondary air passages and replacement of G609 sensor + supercharger belt: $2,151.37
04/21/2023 - 178,139km: $16,492.40
Full Timing chain + tensioners (Not just the top ones), Decarbonization, New under intake valves, PCV, Water pump, Complete front suspension arm, Engine mounts, Thermostat, Bilstein complete suspension + H&R OE cup kit 1.5'' drop, Front ECS torsion, bar, Rear H&R sway bar, ECS subframe, differential and transmission inserts
Integrated engineering stage 1 = 416 HP & 391 FT-LBS (DATA LOG attached)
02/10/2023 - 182,953km - Clutch pack + oil change: $3,979.63
09/11/2023 - 183,664km - Replacement of clogged catalysts by CTS Test pipes : $3,213.60
I also have some front wheel bearings somewhere in there.
*All in CAD $*

Few questions for the community.
1. Would you still keep the car or sell? ;)
2. For anyone with test pipes, how did you get rid of check engines P0430 & P0420?
*Note that since test pipes, i went from 400km/tank to MAX 350km/tank and also lost +-11 FT-LBS*
3. Based on your experience, what will be the next repair?
4. Can i safely go stage 2 single 180 crank pulley without HX?

(Living in Montreal, Canada)

[Bartlett]

Post-100k miles, having known what I know now, I'd have sold my car. Although the 3.0T, especially later years, is a somewhat reliable and rather powerful, uniquely supercharged engine, the laundry list of problems or deficiencies (think carbon buildup) is too much. Considering what has been done to the car already, I wouldn't expect a ton of problems to arise.

[jthan.ami]

Personally I would have called it at the Timing Chain and tensioner replacements. For less than the price you listed up there you could just buy a used Audi S4 engine here at least here in the USA. I'm right at 100k mi with a 2016 b8.5. Hoping to get at least 3-5 more years and another 50k. I've heard of some hitting 200k mi without severe problems.

Up to 100k miles or 160k km: Carbon cleaning, PCV valve stuff, rear shocks, these are really expected items. The key to these cars is maintenance and doing 'while you are in there's' with a shop you can trust. I scan my system for codes regularly. I maintain all the fluids (10k mile oil change is hogwash 6-7k tops, less if being real harsh on it). My PVC coded intermittently between 75-90k with no check engine light. I knew what was up. Pulled gas cap to get the CEL. Took it to shop and got the PCV done under the extended warranty (another great investment when you get these new or slightly used).

While S/C was off we did the valve cleaning, hard coolant lines (upgraded them to metal from plastic) changed belts, thermostat (as precaution) and a few other things. Got about $6k of work done for around $1.2k. Aside from that early on less than 50k mi water pump went out. Factory warranty replaced it with the revised part. At 100k and no failure. Shop says the water pump can be replaced w/o pulling the S/C but not the thermostat.