Four-year service coming up - wondering what might be worth getting done.

Would defo think about rear diff oil changed. The RS5 gets it done every 20k I think and it's the same as the one in the S4. And at stage 1 it might be worth while. Changing the oil in the supercharger wouldn't hurt.

https://www.audizine.com/forum/show...e-how-to-(transmission-and-rear-differential)

Details in this.

Might hold off on the supercharger oil change.

https://www.audiworld.com/forums/s4...134/supercharger-oil-change-interval-2826361/

But then again what harm can it do and it's not expensive.

Mine is 5 this June and I've been wondering the same thing. I've not done an aircon service so thinking about that for year 5. Brake fluid is up again. Beyond that I'm unsure. Spark plugs and air filter were done at year 2 due to a booking mistake. Looking at the invoices I see no sign of a pollen filter change. Did S-Tronic oil last year (early) .

I guess supercharger belt and pulley need checking at some point. Beyond that I'm unsure what the long term service items are. No cambelt but that has a side effect. Cambelt implies water pump and coolant change. If there's no cambelt change does the coolant need changing at some point?

MuPPeT_ON_TouR said:

Would defo think about rear diff oil changed. The RS5 gets it done every 20k I think and it's the same as the one in the S4. And at stage 1 it might be worth while. Changing the oil in the supercharger wouldn't hurt.

https://www.audizine.com/forum/show...e-how-to-(transmission-and-rear-differential)

Details in this.

Click to expand...

Is the rear diff oil the same as the 'gear oil for sport differential'? The service schedule booklet that came with the car states 38,000 miles for the ATF oil and gear oil for the RS4/5/6/7.

Mine is 5 in August and will be on maybe 35,000 by then so I'm having similar considerations. Will probably ask to have the sports diff oil changed at the same time as the DSG oil then, so only a little earlier than the book recommends.

There's nothing I can see about air-con service in the schedule, a little sceptical about the need for it, but happy to be educated on the matter.

It says 57,000 miles for the engine 'air filter element' but also states 'when the engine is driven in regions with high particulate emissions (especially soot from diesel engines)' to do it more frequently. So as our roads are clogged with diesel cars probably good to do that and the pollen filter more frequently. Pollen filter is an easy DIY job, engine air filter looks more involved.

Jeff, if you are on stock brakes and pads then you can wait for the indicator, however I'd say that at 35K the pads will likely be low. However you have the same wheels as me so it's p**s easy to check yourself.

I doubt your belts need replacing yet, however when you do it is wise to replace the tensioners, and of course you have that rubber-filled stock pulley, many of which have failed for other owners. You should be safe at 35K, but you can never tell. Anyway don't treat the belts as a simple job - best have the whole pulley system inspected.

As per @MuPPeT_ON_TouR, I think its the oils that Audi says don't change that should be thought about. Supercharger oil is too early, especially considering that you have the CREC so the SC spends a fair amount of its time in idle, particularly compared to the former engine. Its the gear oils that will need attention at some point, and also the transmission fluid if you have the sports diff. Like you I decided to have my s-tronic ATF changed at 3 years irrespective of mileage. I'll have it changed again at 6 years, which is when I'll have the gear oil changed too. That leaves the sports diff. I've only just done 17K so I decided not to have it done at my 4 year service which was done last month. I think I'll have it done (both fluid and gear oil) next year.

As you have done 35K, I'd recommend getting your rear diff serviced.

@scotty76 - your engine doesn't have a cambelt - that job is done by those chains at the back of the engine. Also fyi my pollen filter is changed every year.

Personally I'd leave the aircon alone whilst it works - unless you are one of those people who turns it off for periods.

Engine coolant, if it is still the factory fitted G13 then it will last for a long time, I have a February 2011 S4 and I bought a coolant test kit which is just a tube of tester/indicator strips, the ph level in my coolant is still "very good" - coolant starts life as being slightly alkaline and as contamination from surfaces affect it, it becomes acidic and that is why it needs replacing - so that means at over 8 years and only 25K miles, my coolant has a long way to go before it requires to be changed, also the freezing point is okay as is the concentration level - these last two should tie in.
I think that initially back in 2011 and maybe longer, plugs + air filter required replacing at 6 years or 60K, I replaced mine at 6 years, the pollen filter should get replaced every 2 years and if you are being tight, just remove it and back vac any dust out of it and check for leaves etc in the ducting. I've chosen to fit a proper pollen filter, ie Frecious from Mann, I don't think that VW Group have caught up with that option yet, original should be Mann filter with carbon impregnated in its incoming air surface.
The initial worry about water pumps in VW Group world was based on VW Group sometimes spec'ing plastic impellors and they could break up or just crack and come loose, I'd doubt if these cars have any issues with impellors, but when you run a car with a cam belt driven water pump, it makes so much sense with the old impellor issues and the fact that if a water pump bearing fails it will wreck the engine/belt and it is easily changed when the cam belt is changed - is what makes replacing the water pump with cam belt a good plan - so that is not an issue with these chain driven engines.

Edit:- AC servicing, it should get treated to a detergent "bomb" every couple of years, if it is still performing ie chilling as it did when new, then I'd not bother going the bother of removing the charge, checking for leaking and recharging - these cars, well at least from MY 2011 onwards, do not decouple the compressor with an electro magnetic clutch, the compressor is a variable displacement type so is always moving fridge gas and oil round the system, just in a lower volume than when actually being demanded to chill the cabin air, so it does not matter if you use or do not use it. Personally I hardly ever need to run the AC chiller but I check its performance in terms of Hi/Lo pressures and vent discharge minimum temperature every summer - again it is still okay, slightly lower running pressures as years go on, maybe this year I'll add in "some" R134A to take it back to where it should be as all these systems do lose some of their fridge gas charge over time across "plastic" O-ring seals and the flexible pipes - its all down to atom sizes - the plastics behaving like a sieve and letting a small weight of gas to escape every year.

@Dippy I think you misread my comment. I understand it's a chain. What I was getting at was a side effect of cambelt changes is a replacement of the water pump and coolant. As this won't happen on the S4 because of the chain does the coolant need changing at some point?

jdp1962 said:

Sports diff fluid change: £66

Click to expand...

That price is likely for the transmission fluid only. You know that it has separate gear oil as well?

The only way to find out if the oil "needs" changing is to test it. As you know I've had used oil analysis done, including for my gearbox ATF, and according to the TBN and TAN measurements, none of those oils and fluids needed changing. I'll have both changed on my sports diff next year purely because it will be efficient to have them both done at the same time. I was only checking that you realised it was only the fluid and you do so that's OK.