cliffcoggin

That's exactly what Gareth, and now I, are getting at. A simple voltage reading at minimal load will not reveal defects within the battery. That is why battery testers often use deep discharge equipment which simulate the 200 or more amps drawn by the starter motor. That is not to say your battery is definitely defective, but until you prove otherwise I would regard it as suspect, because failing batteries are often the cause of unexpected electronic problems and errant error codes.

A wise choice. To have passed a test with visibly defective lights would not fill me with confidence with regard to the condition of the rest of the car.

Meaning what precisely?

Michael. The OP has not been back to the forum for more than five years so you are unlikely to get a reply. I suggest you start a topic of your own if you can not find similar topics in the forum history.

I suggest you find and test the handbrake switch as a first step. It may be seized by debris if it is on the cabin floor or under the carpet.

Thanks for letting us know.

There's little I can add to Richard's reply. Normally you would be entitled to reject the car within 30 days of purchase if it proves to be defective, however you have queered the pitch by modifying it since purchase so the dealer has a counter argument. Mapping out the Adblue system instead of repairing it makes me wonder if he really replaced the cam belt and water pump. That is an expensive job that would have eaten most of his profit.

I'll cross that bridge if I ever come to it, as I expect to expire long before the car does.

That's an odd reason. You could apply the same rationale to any other part of the car such as the engine or the suspension or the electronic systems. As long as the gearbox of any propective purchase has been correctly serviced you should have no qualms about it.

Did you code the new battery to the car? That alone may be enough to explain the fault codes.

I hope you will not be returning to the thieving sharks at Audi who wanted to sell you a new engine.

I realise that. I was agreeing with Steve Q's suggestion that the heater matrix might be blocked, and commenting on the likely cost of renewing it. The water pump and cam belt would never have cured lack of heat in the cabin, though they may well have been necessary for other reasons. Count yourself lucky the job was so cheap at only £500; it would have been half as much again at most places.

Why would you try such a thing? It's a car, not a boat.

I consider myself lucky to have paid no tax, (or Road Fund License as I still think of it,) for three years so I am not unhappy. Roads need to be paid for, and if it was not Rayner taxing us it would be another Chancellor of any political persuasion you care to name. Sorry chaps, but I shall continue to discretely laugh up my sleeve at you unfortunate fellows paying exorbitant prices for liquid fuel plus duty plus 20% VAT, while I refuel on cheap overnight electricity plus 5% VAT.

I see many reports in the forums of Adblue problems caused by crystallisation that normally require expensive replacement of tanks/pumps/sensors etc. As a chemist and a chemical enginner I know that the main component of the stuff is urea which is very easily soluble in water, so in principle it should be simple to clear any blockage by flushing with water. Has anybody tried to do such a thing? I realise it would need some sort of electronic interface to the car to force open valves and run the pump and so on. That sort electrickery is well beyond my competence, and as my A3 predates Adblue I have no experience of it, hence my question here.

Please let us know the outcome.

Unfortunately a private sale leaves you little chance of recompense. It's strange a modification has been done on such a new car. Did he use it to tow caravans by any chance?

Hundreds of pounds sound about normal for new heater matrix. Look up similar threads on this forum for more detail.

Nice result Mark. Any idea how many hours of work it needed?

Sorry Mike, I meant to write independant VAG specialist as opposed to Audi dealer. It was getting late in the evening.

I have read of the same trick elsewhere. Not much use to me as mine is taxed from February.

Glyn. Did you buy the car from Edinburgh Auto or from a private vendor?

Have you eliminated wheel balance and tyre wear as a first step? If so, I agree bearings or brakes are most likely, but don't dismiss CV, steering, and suspension joints as possible causes.

That would depend on which engine is fitted, which you have not mentioned.

Edd. The normal amount of water to be expected in oil is none, zero, nil, nada. That you have had some emulsion from the time you bought the car 18 months ago indicates the engine was defective when purchased, so it is not surprising it is now a lot worse and is in urgent need of attention to avoid complete seizure. I suggest you stop using it immediately. Head gasket failure is the least probable cause of the problem, and would usually show itself with other symptoms.