cliffcoggin

Allowing the battery to flatten will have damaged it, which is why it will no longer hold a charge. That damage will also interfere with the cars electronics and may explain many of the faults you experienced. I suggest you buy a new decent quality battery of the right capacity as a first step, and then get any remaining error codes checked on a code reader such as OBD11. Let us know how you get on.

How old is the battery? How many times has it gone flat?

Let's not confuse a soluble carboxylated silicon compound with silica gel. They are two different things. Amongst some of the uninformed nonsense I have read on this subject is an opinion that silica should not be used because it is abrasive, and indeed silica is abrasive, but silica is not what is added to antifreeze. Silica is not the same as silica gel which is not the same as a carboxylated silicon compound. The soluble carboxylated silicon compound is a corrosion inhibitor that reduces the electrochemical reaction between iron and aluminium. It is not solid and therefore can not block coolant passages. (Incidentally aluminium has been used in engines for many decades before 1996.) Silica gel beads on the other hand are used throughout the commercial and industrial worlds for absorbing water, which I presume is their function in the expansion tank, because most hydraulic fluids are hygoscopic, i.e. they absorb water which degrades their performance. For example you will often find small bags of silica gel beads in the packaging of steel and iron goods to protect them from rust during storage by keeping the atmosphere dry in the pack. None of which gets us any closer to solving your lack of cabin heating. I don't know if the absence of a Mit Silicat mark can be taken as proof that there is no silica gel present, so you have nothing to lose by back flushing the entire cooling system in stages. As the scale of this silica gel problem becomes more apparent to me, I now wonder if some of the reports we get on the forum of unexplained low engine temperatures are related. I imagine that these beads can easily prevent a thermostat from fully opening or fully closing. They could also be clogging the coolant pump, which of course is designed to pump liquids not solids.

It may well be all current models for all I know, but not necessarily all years. I am fairly certain my 2007 A3 did not, so it must be an innovation that was introduced since then.

See this: https://www.audiownersclub.com/forums/topic/28121-ignition-light-disco/

So is your expansion tank marked "Mit silicat"? If so, that is likely to be your problem.

That's a pity. The information would have been useful to others with a similar problem.

I have read reports on this forum of a bag of silica gel in the cooling system breaking up and clogging the heater matrix. I don't know which models are affected by this problem, so it would be worth searching the forum history over the past year for more information.

Thanks for letting us know. I am surprised that faulty wheel alignment was not detected earlier because the symptoms are easy to detect. The inner or outer shoulders of the tyres are scrubbed off depending on whether the wheels toe in or toe out.

Please tell us the name of the company that repaired the ABS module.

The ability of a battery to crank the engine is not proof that it is in good condition.

I could speculate endlessly about the cause, but what's the point? Take it back to the vendor for free repair.

Fair enough Ryan. I have reservations about resting a foot on the pedal at all times. My driving instructor (my father) would slap my leg when I did it, but I daresay that behaviour would be frowned upon now. Nevertheless I reckon it's more likely to be a fault in the hydraulic system such as air or worn cylinder seals.

The prime candidate to my mind is a dying battery. The recent cold weather is revealing the weaknesses of all batteries. If it is the original five year old battery I would not hesitate to change it; if it is more recent I suggest you get it professionally tested before buying a new one. Make sure you get any new battery coded to the car.

Pardon me if I snigger, but glad the solution was so simple in the end.

Ryan. The only reason for a clutch to overheat is slippage, caused either by poor driver control or severe wear. If you can eliminate those factors then there must be a fault in either the master and/or slave cylinder. How many miles has the clutch done? Does the driver ride the clutch at junctions etc? Is the clutch "bite point" about half way up the pedal travel when it is working? Does the engine speed increase without a corresponding increase in road speed? Answers to those questions will us identify where the problem lies.

I would not expect the chain to need replacing for several years yet, though I do not know if or when a scheduled change should be done. Are there any symptoms, such as excessive noise, which lead you to ask the question?

That's a damn good price Chris. Your mechanic deserves a recommendation if you would care to provide a name and work address for him.

That's all very well David, but it does not tell us anything new. I must point out that the report specifically states "The service we provide is essentially an emergency breakdown assistance service and is not equivalent to the service carried out by mechanics working in a fully equipped garage or workshop."

Josh. I see you are in the USA, unlike most of the members here, so the software in your car may differ from those us in Europe. Is it possible there is some state or national requirement for the cruise control to be disabled by the manufaturer?

Gareth. I have merged your two identical topics.

The car is only a year old. Is it not under guarantee still?

Thanks for the information David. It's a shame it is wasted on Jethro110 who has not been back to the forum since the day he posed his question 14 months ago.

Your latest readings only reinforce my opinion that the battery needs to be renewed. However that is only an opinion, not a proven fact, so either you wait for confirmation by a proper test or you buy a new battery now. The choice is yours.

Your new tyres will be smaller than the originals, so yes they will alter the speedometer readings.