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Info credited to Harry Joynes: Hey everyone. Just thought I’d share my hunt for slightly pulsing brakes at low speed and a vibration in the seat at 50mph plus. After much searching the internet it lead me to a wheel bearing however I was thinking warped rear discs. I changed the fronts that stopped the steering wheel shake when braking I thought today I’d just take the wheels and docs off to see if there was anything noticeable and there it was. The hubs between the discs were corroded and pushing the whole lot ever so slightly off straight. Cleans all faces up and now it drives like a dream. Just a free thing to do if anyone is experiencing similar issues. Little before and after pic.

Hi yes the dynamics you state are correct but its not the EGR that blocks everything up but the addition of crankcase gasses which contain high levels of steam/engine oil vapour and its universally accepted engine oil is not a very combustion friendly medium due to the fact it maintains its molecular structure at high temperatures, the fact remains that if you spend hours researching this as I did on the net the pros and cons are all there for anyone to peruse, the manufacturers spend millions of Euros on development to meet the compliance required for emissions and in my opinion if you can live with this and fixing the things that go wrong you can still enjoy the longevity associated with the older models, the key factor is NOX1 reduction as if you take in to account the effect of nitric acid on the respiratory system you then have to ask the question is my enjoyment of my diesel potentially worth a life that is shortened by my vehicles modifications, there are lots of different opinions on what heat does and plenty of blogs on post remap turbo failures due to heat, this debate will rage on until the eventual demise of the Diesel engine in cars, it a bit like who is the true god Christ, Allah, or Jehovah and that ones been going on for hundreds of years with each side firm in the belief that they are right, last and not least in view of the development times and costs do you realistically believe you can delete all these items and still obtain the same results as the manufacturer?. Steve.

As I said, it's the good home rather than the money, but think it's scrap value is £200-300 so would be happy with that.

The hub is there, so the bearing must be there.

Thanks Magnet . More info as you suggested. Have owned car since 2017. It's in reasonable condition bodywise , has full leather seats and factory sunroof. Head lining needs replacing but otherwise interior good .Front end accident damage in 2021 - bonnet radiator and headlights replaced .Good deal of work done on engine in 2022 with rocker gaskets and oil seals replaced , new timing belt ,water pump and coolant hoses . Has now got fresh oil leak and plastic heater core tail has broken up. Needs someone with a workshop and the necessary skills to fix it. Believe not many examples left , so hoping someone is interested in preserving it rather than it being broken and / or scrapped. Love this car ,so it's not about money , it's about finding the old girl a new home .

Also be handy if you know someone with vcds... monitor live data like throttle body position, specified Vs actual readings on fuel rail ect. Also with the rail make sure it's legit sensors and not eBay specials as they cause issues too.

Have you changed the map sensor and fuel regulator sensor? Also check the intake swirl flaps...these can brake then close on their own at high boost as I found out this week .

Could it just be unburnt fuel around the plugs? Just throwing it out there. A3 I had when just left sitting and only run on tick over it developed like a miss then cleaned up as soon as ran again

That makes no sense at all. Either the staff are incompetent or they are trying to defraud you. Either way, take it back and give them another chance, then refer the garage to Trading Standards if you don't get a satisfactory response.

Hi if its proof you need there must be hundreds of posts on here the prime one being look through the C7 forum for a guy called Big Townz he had god knows how much mechanical work and remapping done to his engine, the end result total failure, in essence the whole idea behind Ultra technology was to have a Diesel engine that ran a lot cooler thus producing less Nox1, this was achieved by using a larger coolant radiator with the addition of a low pressure EGR system with its own cooler which operates from start up to cut down Nox emissions until the main EGR valve opens when the engine is up to temperature, there is a fine balance between both systems that are a key to keeping combustion temperatures within limits so producing less Nox the remaing Nox is felt with by the SCR which injects adblue as required to cope with any Nox increase therefore deleting the EGR and increasing the gas temperature by about 40% has a negative effect on the SCR which will over inject to try and compensate, the next stage is delete the adblue system which creates even more heat, it is well known that a hotter running diesel will perform better and give better MPG the problem with tis is that in production of the engine they found the composite of the metals used could be downgraded as for all intents and purposes the engine was never going to run temperatures at the upper level, this saved money, running at higher than manufacturers temps causes turbo failure and even in some cases valve failure which is well documented on the internet mostly on US and European sites, my opinion from ownership is that these engines are already running on the edge therefore why put more strain on them. Steve.

Hi the term Audi use is reducing agent, it is actually adblue and the term is derived from the system our cars use which is Selective Catalytic Reduction, the system works thus, you will have three sensors before the cat one is an exhaust gas temp sensor the other is an oxygen sensor the last one is a Nox sensor of which there are two, the correct designation are upstream for before cat and downstream post cat, before all of these is what is basically a small captive shower head which when commanded by the ECU will spray adblue into the exhaust stream pre the first bank of sensors, the first NOX sensor registers the amount of Nox in the stream and the second registers the particles after the adblue spray and depending on its in formation log may request more adblue, the whole mixture is then fed into the DPF which does its thing with the soot particle entrapment, here lies the problem to make the exhaust cleaner still there is an EGR cooler at the back of the DPF which is attached to another EGR valve which when opened by the ECU at low speeds sucks the already treated exhaust gas through the cooler with drastically cools the gas to so when it is reintroduced in to the engine to be re burnt by the combustion cycle it won't be to hot which reduces combustion temps and burns any Nox 1 that escaped the first time, as I said the main culprit for the blockages is the PCV system as this adds extra engine oil vapour and water vapour neither of which burn very efficiently if at all. thats why Audi recommend longer faster journeys as at higher speeds both EGR valves are shut as the engine needs as much oxygen rich air as it can get to maintain the speed therefore it burns slightly hotter and burns off a lot of the accumulation from town/city driving. Steve.

Hi your regeneration intervals are spot on, with regard to the adblue its not made of pigs urine which would require vast amounts of purification before use, its made of a component in the fertiliser industry which when mixed with de ionised water creates a synthetic ammonia, when subjected to extreme temperature the greater water element turns to steam and along with the ammonia turns the nitrogen oxide particles, Nox 1 into a inert particle Nox 2 which degrades rapidly in normal atmospheric conditions. Almost all the branded adblue sold in todays market are the same and unlike fuel do not suffer with blending differences, the consumption of adblue is very dependent on fuel/oil quality I.E. if you use supermarket fuel and cheap engine oil the regeneration factor will be increased as the amount of soot produced by both is accelerated and the DPF blocks more rapidly as the soot particles will be larger and physically more dense, therefore if you use good fuel and any Quantum spec low SAPS oil you are safe, with the additive going into the fuel as long as it has a Cetane booster that raises the burn quality this promotes much smaller soot particles which burn of more comprehensively from the core filters on the DPF. Steve.

Hi Guy's, I'm a Car Audio specialist (42 years) & upgrade the Audio systems in Audi's all the time, I'm also an Audi A4 3.0 Tdi (B7) Quattro S-Line owner in Kent so I'm deffo not touting for any business, particularly as you guys are far away from me anyway! But I would gladly give some advice if needed? Particularly if you are going to attemp to do this yourself etc! Not only on what I would recommend you do or don't look at buying (Budget wise) but also and more importantly the many additional things to know about Your Audi A4. I.e. Once the original Concert, Chorus or Symphony single or double din Audio Head unit is removed there is quite allot to add or compensate for to add an aftermarket system to all Audi vehicles and not just a simple matter of buying a new head unit and a correct single or double din fascia panel! For example, all Audi vehicles are either half amplified or fully amped (Bose) also phantom (amplified AM/FM antenna) Also the original audio unit will have no acc - ignition feed present in either the earlier A4 - B6 (iso connectors) or the Facelift B7 onward (Fakra -Quadlock 40 way connector) Double din units, the ignition on for all Audi's is achieved via the can bus data pair the goes to the head unit and there is no ignition 12v feed as such that is required to switch on an aftermarket replacement head unit, you can cheat by running a seperate ignition feed to the new audio head unit via the fuse box but this is not a good way of doing it! You will need at least a slim key Can Bus ignition interface at around £45 or if your vehicle has multi function steering wheel commands you will need a Can Bus Steering command interface unit on either ISO or Fakra depending etc These cost about £70.00 but worth getting! You will also need either a full Bose Amplifier retention patch harness or a Half amped patch (otherwise you won't have any rear speaker audio). This would apply to the A3, A4, TT old A6 etc, A4 convertible can be different again even post 2006 to the standard A4 2006 B7 as they follow the audio platform of the 2005 A4 (B6) Confused? Yeah Audi's are real good fun & even doing this daily even I get confused & have to double check all on the vehicle before I quote for any installation of audio change or adding a Parrot Mki bluetooth hf unit! Everyone says Audi are same as VW... "Oh No they deffo are NOT! They are quite unique between the family of VAG & Skoda, Seat etc that are indeed same as VW. Audi however keep us thinking. If you are attemping to install a quality brand of aftermarket head unit such as Kenwood, Pioneer Sony, Alpine or even JVC I'll gladly answer any questions you may have and fire away I'm all ears and will help or advise if I can. If however you have bought one of those awful eBuy Chinese Xtron or similar £199.00 rubbish Android retro (bootfair quality units) send it back now and demand a refund or take it to a field & shoot it. I'm not interested as you can't make a silk purse out of a pigs ear etc * _ *