cliffcoggin

Thanks for the information Josh. That's the level of detail often missing from simple guides.

Glad to hear it Charlie. Some thanks would have been welcome.

It could be a thousand things Jessica, all of them electrical, so it makes sense to ensure the battery, (which you have thrown doubt on,) is in good condition before embarking on some diagnosis. Don't be tempted to renew components at random, or have the ECU remapped unnecessarily, else you will throw thousands of pounds down the drain. You have not, or maybe can not, answer my question about whether the battery was coded to the car when it was renewed, hence my suggestion to get it tested as a first step. Once that has been established, get the car tested with a decent code scanner, not a cheap home tool.

Perhaps, but never having had it happen to me I don't know.

Mark. It certainly sounds like there is no compression. Given that the camshaft is turning, the crankshaft must also be turning. My guess is the belt has jumped a few teeth so that the camshaft is out of phase with the crankshaft. If that is so there is the possibility of damage to the valves so it would be unwise to turn the engine again. I suggest you get the car towed or lifted to a garage for a deeper investigation. Do you have any form of guarantee on the cambelt?

I could not open the logs Syed, but I don't really need to if your words accurately reflect the data. Whether it is worthwhile to pursue a claim is debatable. You appear to have a valid claim but the time, effort and expense of doing so is going to be considerable. Only you can decide if you are prepared for that.

The temperature should remain rock steady at 90 once the engine has warmed up, so Audi are lying to you with their claim that it normally varies from 50 to 90 degrees. Take the car to an independant VAG specialist who should be able to diagnose the idling problem as well.

There is a chance that the instrument cluster is faulty. It's a common problem on A3s, which can be repaired for less than £300. If you want to be certain of the diagnosis you are going to need a better diagnostic tool than that. The usual recommendations are for OBD11 or VCDS I think they are called. Stevey Y will be able to confirm if he reads this.

You say the problem started when the battery was changed, but did you code the new battery to the car. If not, that might explain many of the subsequent problems. I suggest you take the car to an auto electrician for a full diagnosis and hope no permanent damage has been done.

Can we assume you have tested the fuse? Have you checked the mechanical parts of the door lock to ensure they are not jammed?

Clean the oil off the pulleys and fit a new belt. Belts rely on friction to transmit drive so it makes no sense to spray oil on it.

Is this a recent change in behaviour or a problem that has been present since you owned the car?

If the heater was working prior to losing coolant there is a fair chance that the system is now airlocked. Try applying suction to the reservoir to make the air expand and find its way up. Of course that will be a waste of time unless the cause of the coolant loss is rectified first. Was there a high temperature warning or any other symptoms of overheating?

Happy to oblige. Do please let us know the outcome.

Are you aware that water is formed as condensate from all heat exchangers that cool the air passing over them? Refridgerators, freezers, aircon systems all work the same. Whether you call the water stagnant or something else, the odour comes from the mould that grows in it. Most of the green moulds are harmless but smelly, the black and red moulds are less innocuous. Either way the solution is drain the water from the AC as it was designed. Do that and you won't need bombs, perfumes, or other chemicals.

John. The first thing to check is the battery. Get it tested professionally because a simple voltmeter will tell you nothing about its internal condition.

Ian. You have two identical topics running in separate forums which are both attracting replies. Please delete one or the other to avoid any confusion. Let me know if you can not do that and I shall sort it out somehow.

Masking the odour of mould with perfume does not solve the real problem, which is stagnant water. Eventually that water will rot the carpets and rust the steel, so it would be better to get it out of the car.

Do let us know the outcome.

John. Believe what you want, but 911s have positively old fashioned electrical systems compared to your A3, which requires a stable electrical source to avoid erratic and seemingly unrelated electronic problems. The voltage you measured tells you nothing about the real condition of your battery, so Gareth's recommendation to get the battery professionally tested is spot on. That means a high rate of discharge during the test in the region of 250 amps rather than the 0.005 amps of a simple voltmeter.

If you still have the noise Spenser I suggest you take it to an independent VAG specialist to be assessed, and simultaneously inform the car vendor in writing that he may face a claim against him for any repair. It seems from reports on this forum that dealers are increasingly averse to admitting to, and rectifying, faults on the cars they have sold. I guess squeezed margins are leading them to cut corners and become more deceitful if that is at all possble.

Any progress on this Steve?

That's the price we pay for having so many electronic gadgets on our cars.

Ah, the notorious dealer warranty. Sadly, none of them are worth the paper they are written on.

Michael. While the problem may be any of those that Gareth listed, there is also a good chance that the battery may be at fault if it is more than say six years old. The 12.8 volt reading tells you nothing about the internal condition of the battery so I advise you to get it tested professionally. The reason is that the car's electronic systems are sensitive to seemingly trivial power variations.