RS4 B7 Buying Guide Sticky
Posted: Sat Mar 26, 2011 8:43 pm
This is an edit of the Audi Driver magazine guide - feel free to add to it
DRC Suspension
Originally used on the C5 RS6, the DRC system produced by Japanese [deleted text] manufacturer KYB again hasn’t been proving very reliable with depressurisation and leaks widely reported. So much so that Audi UK has extended its warranty cover to 5 years or 75000 miles though due to its rarity not every Audi Centre is equipped or sufficiently competent to deal with repairs effectively. Some cars have managed to pass 75000 miles with no work required while other have had issues much sooner so durability may relate to the number of speed humps and pot holes the car encounters.
Symptoms of DRC failure are knocks and bangs from the suspension and a general feeling of instability especially when braking and cornering. As with the RS6, conventional aftermarket suspension is an alternative but DRC is key to the RS4’s excellent ride and handling balance so it’s well worth retaining.
Vacuum System
The RS4’s powerplant has a complicated network of vacuum pipes that control the intake manifold flaps, the airbox intake air change over flap and the valves in the exhaust tailpipes. If there is a break anywhere in the circuit then none of these items will operate and in the case of the intake manifold flaps, the ECU will <beep> the timing to protect the engine and restrict power output. A basic check can be made by activating Sport mode while idling and listening for the exhaust note to deepen or visually observing the exhaust flaps opening which confirms the vacuum circuit is intact but VCDS diagnostic software allows a more in-depth examination. The intake manifold flaps, intake air change over flap and exhaust valves can all fail individually too.
Exhaust flaps.
The vacuum operated exhaust flaps are prone to seizing. They are closed by vacuum so with the engine off they should be open. A torch is needed to inspect them. With the engine warm and idling the flaps should be closed until Sport mode has been activated. Replacement can be very costly, Audi quote around £800 for one side. Lubrication and some general encouragement with a bar to manual open and close them can help.
Carbon Fouling
Carbon deposits within the inlet tract which is generally accepted as being caused by valve overlap, a feature of the FSI system. Symptoms can be exhaust smoke, lack of power and in extreme cases, misfiring. Initially it was thought that it was due to excessive oil vapours from the crankcase ventilation system but oil catch cans retro-fitted to some cars have remained largely dry. While many cars will be fouled internally with no problems, only very few actually exhibit any symptoms and these tend to have performed frequent short journeys in urban areas or steady motorway cruising with little use of high revs. If cleaning is required this can be performed by a specialist for around £600 but how long it will remain clean is unknown. Impossible to check before buying really.
Bucket seats
There have been reports of the electric adjustment facility of the front seat bolsters failing and repair is far from straightforward. It is possible to prevent them from tightening on activation of Sport mode by disabling active mode via the Drivers Information System menu which should extend their life. The bucket seats can also suffer from excessive wear on their outer bolsters which can reflect the care taken by the driver when exiting or entering.
Brakes
Some cars requiring discs and pads as early as 15000 miles, some owners complained about new discs juddering within just 1000 miles. Other issues are cracking and blockages of the drill holes and a design fault with the original pads that can lead to them excessively scoring the disc before the pad wear sensor light illuminates though replacement pads have been redesigned to rectify this.
With the list price for front discs and pads totalling well over £1000 from Audi (pads alone are £263!) it’s important to take this into consideration when valuing a car as many offered for sale will soon require replacement and Audi are the only source for the discs. The rear brakes tend to last longer, though on higher mileage cars, don’t ignore them as while the pads are cheaper, the discs are a similar price to the fronts.
Tyre Pressure Monitoring System
The sensors located in each wheel have a finite battery life and cost around £80 each from Audi though GSF list OE spec Beru sensors for around £60. They can also be damaged by tyre fitters if care is not taken. A number of cars have recently suffered failure of the TPMS system due to an antenna fault. While the part is not expensive at around £70, its location behind the rear bumper makes replacement awkward. It is possible to disable TPMS to check a seller hasn't done this, using the DIS to see if the TPMS menu is still there.
Auxiliary radiators
As with the V8 S4, the RS4 can suffer leaks from the auxiliary radiators which are located on each side of the main radiator, symptoms are pink coolant dripping from the front of the wheel arches and steam from the foglight area. Leaves and debris accumulate in their fins and this eventually leads to corrosion but this can be prevented by regular cleaning using a soft brush and a vacuum.
DRC Suspension
Originally used on the C5 RS6, the DRC system produced by Japanese [deleted text] manufacturer KYB again hasn’t been proving very reliable with depressurisation and leaks widely reported. So much so that Audi UK has extended its warranty cover to 5 years or 75000 miles though due to its rarity not every Audi Centre is equipped or sufficiently competent to deal with repairs effectively. Some cars have managed to pass 75000 miles with no work required while other have had issues much sooner so durability may relate to the number of speed humps and pot holes the car encounters.
Symptoms of DRC failure are knocks and bangs from the suspension and a general feeling of instability especially when braking and cornering. As with the RS6, conventional aftermarket suspension is an alternative but DRC is key to the RS4’s excellent ride and handling balance so it’s well worth retaining.
Vacuum System
The RS4’s powerplant has a complicated network of vacuum pipes that control the intake manifold flaps, the airbox intake air change over flap and the valves in the exhaust tailpipes. If there is a break anywhere in the circuit then none of these items will operate and in the case of the intake manifold flaps, the ECU will <beep> the timing to protect the engine and restrict power output. A basic check can be made by activating Sport mode while idling and listening for the exhaust note to deepen or visually observing the exhaust flaps opening which confirms the vacuum circuit is intact but VCDS diagnostic software allows a more in-depth examination. The intake manifold flaps, intake air change over flap and exhaust valves can all fail individually too.
Exhaust flaps.
The vacuum operated exhaust flaps are prone to seizing. They are closed by vacuum so with the engine off they should be open. A torch is needed to inspect them. With the engine warm and idling the flaps should be closed until Sport mode has been activated. Replacement can be very costly, Audi quote around £800 for one side. Lubrication and some general encouragement with a bar to manual open and close them can help.
Carbon Fouling
Carbon deposits within the inlet tract which is generally accepted as being caused by valve overlap, a feature of the FSI system. Symptoms can be exhaust smoke, lack of power and in extreme cases, misfiring. Initially it was thought that it was due to excessive oil vapours from the crankcase ventilation system but oil catch cans retro-fitted to some cars have remained largely dry. While many cars will be fouled internally with no problems, only very few actually exhibit any symptoms and these tend to have performed frequent short journeys in urban areas or steady motorway cruising with little use of high revs. If cleaning is required this can be performed by a specialist for around £600 but how long it will remain clean is unknown. Impossible to check before buying really.
Bucket seats
There have been reports of the electric adjustment facility of the front seat bolsters failing and repair is far from straightforward. It is possible to prevent them from tightening on activation of Sport mode by disabling active mode via the Drivers Information System menu which should extend their life. The bucket seats can also suffer from excessive wear on their outer bolsters which can reflect the care taken by the driver when exiting or entering.
Brakes
Some cars requiring discs and pads as early as 15000 miles, some owners complained about new discs juddering within just 1000 miles. Other issues are cracking and blockages of the drill holes and a design fault with the original pads that can lead to them excessively scoring the disc before the pad wear sensor light illuminates though replacement pads have been redesigned to rectify this.
With the list price for front discs and pads totalling well over £1000 from Audi (pads alone are £263!) it’s important to take this into consideration when valuing a car as many offered for sale will soon require replacement and Audi are the only source for the discs. The rear brakes tend to last longer, though on higher mileage cars, don’t ignore them as while the pads are cheaper, the discs are a similar price to the fronts.
Tyre Pressure Monitoring System
The sensors located in each wheel have a finite battery life and cost around £80 each from Audi though GSF list OE spec Beru sensors for around £60. They can also be damaged by tyre fitters if care is not taken. A number of cars have recently suffered failure of the TPMS system due to an antenna fault. While the part is not expensive at around £70, its location behind the rear bumper makes replacement awkward. It is possible to disable TPMS to check a seller hasn't done this, using the DIS to see if the TPMS menu is still there.
Auxiliary radiators
As with the V8 S4, the RS4 can suffer leaks from the auxiliary radiators which are located on each side of the main radiator, symptoms are pink coolant dripping from the front of the wheel arches and steam from the foglight area. Leaves and debris accumulate in their fins and this eventually leads to corrosion but this can be prevented by regular cleaning using a soft brush and a vacuum.
) that some RS4 could have some clutch failure, due to "intensive 1 and 2nd gear full acceleration". Has this been related in UK ?
