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I acquired a 2003 S8 a couple of months ago. I've since read thru about 20 pages of comments and advise. This seems to be a very helpful and knowledgeable group and I have questions. I've been owning and maintaining specialty cars for 40 years however my IT and internet skills are limited.
I'm an enthusiast of older supersedans and older sports cars, primarily Porsches. I currently own a 1992 Mercedes 500E which I have restored completely with the help of a similarly knowledgeable forum so I'm familiar with and expect to encounter lack of parts availability. On to the car...
The car is a 2003, black on tan, that was a lease car among three or four dealers and was maintained by the book for around 100,000 miles. It currently has 150,000 miles on it and is in excellent shape. It's been serviced mostly by the dealership. I've taken it to a local good, but expensive shop for a few issues and to get a baseline to work from. I'm not versed in OBD testing or scanners (see above) but willing to learn in time.
These are the current issues according to their inspection and smoke test..
ABS light on for rotational rate sensor.
Transmision warning due to failed range switch
Rear diff leaking on the passenger side
Fuel flange on passenger side of tank needs to be replaced (CEL)
Questions/comments
Is the rotational rate sensor found under the drivers seat inside the car? If so, how is it removed? Loosen the seat and tilt it for access?
The transmission is shifting fine. It showed no warning until I let it sit after purchase and let the battery drain. I've since kept it on a charger as I own multiple cars and the last time I drove it the warning did not appear. I will clean the connection if someone can point me to its location and possibly comment on how to access it.
Rear diff seal I should be able to handle. Best place to purchase the seal and any tips?
Thanks to some reading here, I've purchased a complete timing belt/water pump/thermostat/tensioner/pully kit from FCP.
I found and purchased the fuel flange thru here. How is this accessed? Thru the trunk or under the car?Does the tank need to come down?
I've already replaced the missing link rods for the variable intake plenum. I have access to good parts cars BTW. Nearly everywhere I look the 2003 model is not mentioned/covered. Are there differences between the 02 and 03 models I need to know about?
I'm aware of the HP Transgo kit and will order one shortly. I'm currently not driving the car.
I really like the car and look forward to sorting it out. I'll post some pictures when I learn how although all of you know what they look like. I'm also wanting to remove the door panels to correct some failing inserts. Any guidance is appreciated. Thanks!
Hi, welcome.
Rotational rate sensor sounds to me like your standard ABS sensor. VCDS can tell you which corner of the car is affected. It's usually frayed wiring in the sensor and attached harness. The D2 sensors are unique but less expensive ones can be spliced in if you prefer.
Rear diff might be the output shaft seals, I did both of them on my 2001. I think I recall the trick was that it was easier to get the axle out with the rear suspension compressed to road height vs hanging. That was unusual.
If any of the CV boots or wheel bearings need attention this is a good time. Some have had good luck with a leak stopper ATP AT-205 for this issue as well.
Fuel flange, not sure if you mean the lid of the fuel sender and fuel pump assembly cover? Access is from inside the trunk, there are some youtube vids about changing the fuel pump that show it pretty well. This lid cracks and can cause a small evap leak. It can also be an issue with the gasket related to a fuel pump replacement and at your mileage you might have had that done. If not you should replace the fuel pump soonest.
>Are there differences between the 02 and 03 models I need to know about?
Not much, I use 2002 when looking up parts due to confusion over build date and model year. Audio, On Star, trunk emergency release, Trans ECU...
Re: the Transgo valve, I now recommend also replacing the valve body housing it lives in for an additional $150 or so from Eriksson Industries. On my 2003 this housing was badly worn deep down the bore of that valve where it was difficult to see.
The valve body I believe is 1058 427 022 or 1058427022 .
A helpful vid:
Other stuff I recommend are:
Serpentine belt tensioner roller - search this forum for a Hyundai 2.7 part that works
Serpentine belt idler - you could repack the bearing or just replace the idler.
Fan support bearing - as above, or be sure to do it with a timing belt before 200K or so. Check for noise when the serpentine belt is off.
Alternator bearings, repack or replace. Alternator brushes or voltage regulator - replace when you next find yourself near the alternator.
Front wheel bearings: if you have an axle out to do the CV boot or the front axle shaft seal get that bearing replaced. The front axle shaft seals on both my D2s were dripping before 140K miles and I'm starting to think my 2003 with 133K on it is going to need wheel bearings. In any case if you birth an axle do the related bearing and seal.
Overall it's a great car and the work they need is not bad if you stay ahead of it and combine jobs to save labor.
Cheers, -Joel.
A huge thank you for that comprehensive response!
After reading, I question whether the tech knew as much as I gave credit for. I'll post the notes they gave with associated part no.s where they were available. My writing, their numbers. I'll check all the wheel sensors first. Is VCDS A scanner? If so, what is the best one to have that will suffice? While I'm discussing diagnostics, what/where is the best source for a repair manual or information for service?
Thank you for the link on the transmission range switch! BTW... I do have a lift here.
Yes, the diff leak is the right output shaft seal. Where is the best source for parts beyond the stealer? All four axles have very vice boots and are dry. This led me to believe they have been replaced. I have not been to the dealer yet to try to obtain service records. Is it likely they are original in this shape at 150,000 miles? I've never tried any of the leak stop products however I actually have some of the AT205 a friend gave me. As a side note, he claims this product is the best way to revive and preserve exterior rubber parts!
I wasn't sure what the fuel flange was either so I bought what you see on reading posts here on fuel system failures. What fuel pump manufacturer is acceptable and where should I be looking for parts? (Once again)
Thanks for the additional info and video on the Transgo and valve body. I'll get both after I watch the videos. I'll also attend to your other recommendations as I agree the way to service these older cars is to do everything "while you're in there." Apologies for my lack of internet/computer/diagnostic devise knowledge. I realize it makes helping me more difficult.
> Is VCDS A scanner?
It reads codes but is a comprehensive computer interface tool similar to what the dealership uses.
> If so, what is the best one to have that will suffice?
Dunno, I have had VCDS since the Earth cooled and have not shopped around. For my Cayenne I have a code reader / scanner that is smarter than a regular code reader, it's not even capable of doing an SRI reset though. I think it can tell me which coil is bad if I have a bad coil though, and show realtime data. So you can decide what you want your scantool to do and shop accordingly.
> what/where is the best source for a repair manual or information for service?
No idea, others may chime in.
> Where is the best source for parts beyond the stealer?
I get a lot of stuff from FCP Euro, sometimes stuff from Rockauto. The wholesaler closeouts from Rockauto can be a real crap shoot. I only get those if I have time to check it and complain if it's the wrong part or used or whatever.
Good for filters and belts sometimes.
> Is it likely they are original in this shape at 150,000 miles?
I would expect the front outers to have been changed by now, turn the wheel and see how badly they are cracking in the creases.
> I've never tried any of the leak stop products however I actually have some of the AT205 a friend gave me. As a side note, he claims this product is the best way to revive and preserve exterior rubber parts!
Might be. I think it's good for a seeping seal, not sure I would use it in engine oil but in a diffy it's probably fine.
>I wasn't sure what the fuel flange was either so I bought what you see on reading posts here on fuel system failures. What fuel pump manufacturer is acceptable and where should I be looking for parts? (Once again)
I'd look for tool marks on the fuel pump assembly lid, there is a good chance it's already been replaced. Your picture is the seal for the RH fuel level sensor I think. The flange can also be the big seal around the fuel pump assembly which is hard to get to seal after a fuel pump replacement. Cracking around the long bolt head that holds the fuel pump assembly down is common also.
Only the VDO OEM fuel pump is an option (AFAIK) and FCP is a fine source: https://www.fcpeuro.com/products/aud...-s8-4d0906091c
Sounds to me, with my limited computer/scanner skills, I may be better off using a capable shop to scan and reset things. None of the boots are cracking at all. I feel the same about the AT205. I'll just go ahead and access the fuel system and have a look. This particular item is what is preventing the car from passing emissions. Once again, thank you for taking the time.
Drew
As mentioned, I would very much like to know what other DIYers are using for factory service info.
IMO it's not very realistic to live with a 150K Audi and not at least be able to read and clear codes but I suppose mechanics have boat payments.
Particularly if you take road trips you want to know if your issue is a minor nag (EVAP leak, O2 sensor) or something you should stop and fix.
--update--
Heh, just looked at the pics. Wow, those are some prices. $1500 for an F125? $80 to pop out that interior sensor switch (cheap A6 switch off ebay) and replace it? It's a 5 minute job but I suppose there is a 1/2 hour minimum plus shop supplies.
What computer do they think is under the driver's seat I wonder?
One I noticed about my 2003 vs 2001, the seat memory and B-pillar switches all cracked apart on the 2003. Seems like the earlier plastic parts were more robust, even a few years earlier. Maybe they changed suppliers.
I appreciate the viewpoint. I'm older and avoiding things electronic to enjoy the other pleasures of specialty car ownership. But I think you are right here. On the flip side, not sure yet how much the car will get driven.
Yea, GCR has very good customer service attitudes however it's not the kind of place where one is able to get personal with the techs and get a confidence level. Pricing is HIGH. I felt like questioning the charge to inspect and do a smoke test but let it go due to their honest customer service.
The alarm? switch on the cars' B pillar is broken currently, but operational. I'll be careful.
The small amount of time I've spent driving it supports your comment! When I took possession the variable intake plenum was not working, and the timing belt was an unknown, so I look forward to experiencing 360HP in a 3,800 lb. car. I've driven many cars and the seats in this S8 are some of the best I've been in.
06-06-2023, 01:31 PM
New member and D2 S8 owner
