cliffcoggin

Agreed. There's no knowing if the solution to the leak is easy or difficult, so best to walk away and find something else.

Irrespective of what the guage is reading, or what might or might not have been fitted, or whether any of it is of decent quality, the fact remains that the engine is overheating. That much is at last finally clear, so let's focus on a solution. I still believe you should first remove any airlocks from the cooling system, the A3 being prone to air locks after a thermostat change. If that does not resolve the problem then take the thermostat out and test it. Testing is easy: put it in a pan of boiling water and watch to see if the wax bellows opens. If those actions don't cure the fault then something more serious (meaning expensive) is wrong with the engine. Let us know what transpires.

I too am confused as to whether the car is overheating or not. The little I could see from Gary's shaky video seemed to show steam and hot water spraying out of the header tank, which indicates overheating. If that is not the case we need Gary to clarify what exactly the video was supposed to show.

Well if the temperature guage reads normal yet the engine overheats my first thought is that there is no water circulation. The obvious culprit would be a faulty thermostat, or the system was left air locked after changing the stat. Alternatively the water pump could be faulty, though that should have been replaced many thousands of miles ago on a 1.9 litre diesel. The service history, which you have not mentioned, would show if the pump had been changed.

Gary. Repeating Gareth's question, and adding a few of my own. Did the temperature guage show it to be overheating? Are there any other symptoms like smoke from the exhaust, mis-firing, lack of power, black or emulsified oil in the sump? Do you have a full service history? What engine is it? How many miles has it done?

There is fair chance your battery needs to be replaced. Get it deep discharge tested before believing anything a code reader tells you.

Does the car have a full service history? Did all these faults appear at the same time? Are there other symptoms when the engine is running? There is one thing that can cause all the problems with limp mode and strange warning lights, but I'll not mention it yet to avoid jumping to conclusions.

A single two month delay in changing the oil is insignificant unless the car has covered an extraordinary distance in that time or has been otherwise poorly treated. I would be very surprised if that by itself was the cause of the problem. Repeated delays in oil changing over the life of the car and/or other neglect would be a different matter. Bear in mind that manufacturers advise oil changes at more or less fixed intervals despite the fact that every car is driven differently, and hence wears at different rates. In the absence of continuous in-car engine diagnosis they can do little else, so they always err on the side of caution. Do please let us know the outcome of the diagnosis, and the recommended repair.

Sally. See this for one explanation of variable valve timing and how it is done in some Audi engines. I daresay you can find others. https://www.youtube.com/watch?v=juJ02ZCX9rw Essentially variable valve timing causes the camshaft relationship to the crankshaft to change, thus allowing the valves to operate earlier or later for optimum gas flow under all conditions. I caution against jumping to premature conclusions regarding your engine fault light. Any number of problems that have nothing to do with valve timing can cause the light to come on, so better to wait until the diagnosis has been done.

How very unhelpful of Audi. Perhaps your car was built for a foreign market and has a non UK specification. I can't think of any other reason it would not have the expected wiring. There is another fuseboard you have not mentioned. It is in the dashboard and is accessible by prising off the right end panel. Frankly I doubt the relay you want is there but it's worth taking a look.

Stevey Y told you it would three weeks ago.

Arron. We have been through all this just a few weeks ago in your previous topic https://www.audiownersclub.com/forums/topic/19121-20-tdi-coolant-temp-issues-cause/?tab=comments#comment-68598 Just how much more proof do you want that your battery is clapped out and needs to be renewed?

Congratulations on resolving your problem. Worn differentials are rare nowadays. I guess we shall never know if the particles were the cause of the problem or the result.

As Gareth said, only somebody who has inspected the car can give a realistic valuation, so I shall offer no opinion on what you have seen, except to say the car is worth whatever somebody will pay for it. Only you can say if it is worth £4000 of your money. I get the impression it is not.

Louise. It is not clear how many DFPs you have fitted as some text is duplicated. Nevertheless DPFs, whether aftermarket or genuine Audi, do not need to be replaced every few weeks unless something else is seriously wrong with your engine. I believe whatever garage you have been to is taking advantage of your lack of knowledge, an attitude I thought had died out in relation to women. I suggest you get the engine and exhaust assessed by somebody knowledgable about Audis. I wish I could recommend Audi main dealers, but I can not. I think you will be better served by an independent Audi specialist. If you are prepared to travel to Biddenden for this I can recommend this place https://msautoservices.com/

The calipers on some cars have two bleed nipples. I don't know if the A3 does as my manual is not to hand, but it is worth looking.

I don't know what DRLs are, but my dashboard lights only come on with the sidelights. It's normal behaviour.

https://www.autotrader.co.uk/search-form?moreOptions=visible&postcode=LE12 8AS&make=Audi&model=A3&price-from=2000&price-to=2500&include-delivery-option=on&advertising-location=at_cars

To summarise: the engine knocks under certain conditions, it might be running hot (though I fail to understand how that can be if the guage reads normal,) and it creates emulsion in the oil. (I suspect the increasing level in the sump is caused mainly by water ingress, tainted by a little petrol.) If the knocking is from a big end or a main bearing which has worn the others will be close behind, as will the bores and rings, and a recon engine would be the cheapest solution. I fear you may have bought a clapped out wreck, but before condeming it prematurely I would get the engine assessed professionally. There is a limit to what can be diagnosed from incomplete written descriptions, and you should not rely entirely on advice here before deciding to commit to major expense.

A compression test is just the first step to making a diagnosis of the fault. It may indicate a blown head gasket, a cracked block, a warped head etc. though to be honest if any of those faults were present I would also expect other symptoms, none of which you have mentioned. If none of that means anything to you please get professional advice quickly. The engine is risk of permanent damage if it is run with the quantity of petrol you tell us is in the oil. For the sake of completeness are there any other symptoms you have not told us of? I am thinking of overheating, loss of coolant, brown emulsion in the oil, loss of power, knocking under load, smoke under hard acceleration.

The 1.4 litre petrol engine for a few years was the subject of numerous claims against Audi because of a manufacturing fault causing extraordinary oil consumption. I leave you to look up the details and dates, but if yours proves to be one of the affected engines the only solution is a new engine. Having said that, your engine may not be one of those affected by the above problem, and the fault may lie elsewhere. I suggest you start with a compression test. It shouldn't need saying that petrol in the engine oil will dramatically reduce its lubricating power, and lead to its ruination.

It would be a mistake, and an expensive mistake at that, to change the gearbox until it has been confirmed as the source of the knock. The noise could equally well come from the clutch or the drive shafts (CV joints), neither of which will be improved by changing the gearbox.

Clearly water has got in somewhere, but unless you can see a wet patch inside it is anybody's guess where. Perhaps the most likey entry point is around the bonnet. I would start looking at the fuse box which is at the back of the engine bay, and close to the bonnet edge. Its lid is hard to clip on and may not have been secured properly.

Forgive the apparently silly question, but was it just the outside you washed? I ask because it has been known for jet washers to be used in the interiors.

The cigarette lighter socket is useless for powering accesories for exactly the reason you stated. When I wired in a satnav mounted on the dashboard I picked up a supply from the fuseboard inside the dashboard. Prise off the right end cover of the dashboard with a broad flat screwdriver to reveal the fuseboard. The cover will clip on again if the wire is thin enough.