Dan3222

Sorry, last post before I drive home tonight. Did you try resetting fault codes?

Out of interest which VCDS did you buy and how much? I am wondering if it would read all VAG vehicles?

I wish I had VCDS tbh but not always sure what all the readings mean. But, looking at yours surely it’s pointing to bad connections or a broken wire? Maybe an good old google search with the fault codes and see if you get more info else where. I don’t have time tonight but I will have a good search on it tomorrow, see what I can find on it.

Thanks for posting an update, so many people never bother. My A6 had terrible grip in the wet, the back end squirrelling side to side under even the slightest acceleration around a corner. I thought I had bought a lemon. It was the mix match tyres causing it. Even though they were plenty legal, the difference in age and tread was enough to throw the balance out. I went for Uniroyal Rainsport 3 tyres on all corners and the car was transformed. You just wouldn’t think that ‘odd’ tyres could make such a difference to handling but with all the clever electronics these days they seem to get incorrect signals and try to compensate through diffs etc causing bad handling. Well, this is what I have been led to believe. I am pleased your A5 is sorted. A lovely car!!

Yeah I agree, rubbish paying out so much for same problem. TBH these engines start quite well without even using the glow plugs so I would rule them out for now. Last thing you could do yourself is actually clamp the fuel return hose as soon as you stop the engine. Then take this off before cold starting the next day. This should help rule out fuel running back to tank. If not as Magnet (this chap should be on every forum!!) suggests injector seals could well be the cause, if not it’s the primary pump (in the tank), maybe faulty injector loom or faulty tandem pump. All these things should be testable by a diesel specialist however, though maybe not the injector seals. In the mean time put an injector cleaner in the tank, something like millers. This will help somewhat plus you will get the money back in better economy.

Hi Benny, I think part of the reason there are no replies is because you have chosen a very specific car. I had a quick look myself and could not find one car matching your desires. What a lovely car BtW. Best of luck with your hunt and hopefully one comes available soon.

Other than a broken connection somewhere (I doubt that though) I wonder if it would be the relay that has gone. I would find a local auto electrician and let them have look. Pits also not unheard of to have faulty new bulb?

Just spent a bit of time on the T5 forum searching for this and there are loads of incidences of the 20tdi engine aux belt shredding and taking out the engine by fouling the timing belt. https://www.vwt4forum.co.uk/showthread.php?t=1720247 it seems the common cause is believed to be the tensioner failing.

Is the Q5 a Quattro? I am assuming they all are. These behave best if you have matching tyres on all 4 corners, at a push at least keep the same brand on the two rears and then the same brand on the two fronts. i am a massive fan of Uniroyal rain sport 3 tyres. I have them on the A6 and the VW T5. Hankooks are a good tyre too but are not one I would choose. I would never use Dunlop again. Worst tyre I have ever experienced in the wet.

That is rotten luck, not unheard of either. as far as I am aware your car does have a timing belt rather than timing chain. The serpentine belt is on the same side of the engine as the timing belt. i would be ringing around a few levels cal garages to see what price they can do the job for but if you are getting all new items then you will struggle to get it done much cheaper. a new head complete with valves etc should be around 6-800£ depending on the engine code you have. But you could source a secondhand head, cleaned and prepped for less than £300, down to about £150. A garage would take best part of a day to do the work, there is a lot of prep just to get to the head in the engine bay. Let us know which way you decide to go!

Might be worth trying a good quality fuel additive like Millers. Double dose a full tank of fuel (add before filling with derv) and boot it a bit, higher revs. You should see lots of smoke come out the back for a few miles. This will help clean injectors and also the DPF. If this doesn’t work, unless nobody else has any suggestions I would be taking this to an engine specialist or a VAG dealer and paying for a DPF re-gen.

This is definitely a common fault on the C6. It’s on mine also. I believe from memory there are two floats/senders on the tank, have you found both and played with them? Others have said that the terminals just need a clean. Thought mine had a touch of the fairies and fixed itself but alas it’s not reading at all again. As mine is off the road for a while I won’t be able to attempt to fix it but if I can I will have a look next weekend. Hope you get to the bottom of this soon.

Yes, mine was the same really. I think mine had an advisory on brake discs but that didn’t worry me. Only thing I have really had to do to mine was replace front drop links since taking ownership. wish I had taken my own advice though and checked the lights, it’s had the halogen upgrade but the onboard computer doesn’t like them showing build failure. Yet to see if MOT will fail it because of this since the new rules have come in. good luck with it.

Love my C6 though it’s a 2.7 derv. Body is galvanised so if there are signs of rust there will have been accident in its past. Make sure all ectrics work and turn lights on to see if any warnings come up on dash. Fuel gauges can sometimes play up, this is usually the terminals on top of tank though so easy fix. If it’s a Quattro I found mine was unstable in the wet but by putting matching tyres on back this was sorted. 90k is young for this engine!! Not sure if it has cam belt or not but I am sure you can ask about that. Final thing is out reg number into an app like total car check. This will give you info on last test on advisories.

Any progress Simon?

Network

Certainly on the VW T5 primary pump, the none return valve is built in and it’s this that fails. So a pretty good guess it’s the same with the Audi. Its alway awkward though giving advice on a car that you don’t own or have experience with. Never want to say go buy that item and it will sort it. But 😬 I would be buying the primary pump as my first port of call. I would do this because I choose not to take my vehicles to a garage if I can. Sam, you seem hands on though!?!

Your welcome Nick, sorry I couldn’t help more (my ego still bruised about my 50p bet though). I am really surprised it is the diff still. What a nightmare about sourcing one. Would have been so much better to have had yours rebuilt if possible but that’s not even an option. Best of luck getting a replacement, sure one will come up at some point.

I wouldn’t advise fitting a none return valve until u know u have an issue. Magnets advice is probably best advice in fairness. I have had several vehicles with syphoning back to the tank, my mate has this issue with his Landrover Disco. I told him to keep his tank full and point the front down his driveway. He has been doing this for nearly 6 months now and he gets no issues starting. (His issue is not totally curable with a none return valve though). However, this technique can help diagnose the issue but not the exact cause. Cliffords advice is not quite correct (though I am happy to be corrected and eat my humble pie), diesels rely on a mechanical pump to pressurise the fuel to the injectors, on your car I am sure it is a tandem pump. The primary pump (the electric one in the tank) actually only runs for about 5 seconds, it’s purpose to ensure fuel is delivered to the fuel filter, the tandem pump then takes over. However, his advice is correct but to do this you will have to turn ignition to second position, count 5 then switch off, again turn to position 2, count 5 seconds and repeat. Do this several times and then see if she starts better. I would be very interested to hear however, what the garage says!

Nick, that’s rubbish, that they can’t repair it. Did they say why? I am guessing there aren’t really spares for this diff as they don’t normally go. At least they have confirmed it’s the diff so any money spent will not now be wasted. i would try 24/7part finder or another similar part finder, put in details and then an email is sent to all scrappies that are signed up. Hopefully you will get a better priced seconded hand unit. if not here a couple of specialist Audi breakers to try http://www.a8parts.co.uk/ http://vee-dubs.co.uk/ The following link is for a generic search as I mentioned, you might be lucky. https://www.breakeryard.com/car-parts/audi Best of luck. I guess I lost my 50p bet!!

Rubbing noise? Do you have larger wheels and tires on the A3? They can foul on the inner wing producing a rubbing noise on full lock

You answered my suggestion with the fuel running back to the tank. Have you left it over night with a full tank of fuel? Also if you can leave it parked (with full tank and the front pointing down hill. This should help with the symptoms if it is fuel starvation. might be worth pricing up a new pump for the tank. They are a common fault on VWs especially in the Transporters which I have more experience with. I would assume they are using similar ones. It’s these that fail and fuel siphons back. worth a try anyway.

If I was you I would take it into Bristol transmissions ( there are two more listed in Bristol also). These guys work with all sorts of transmission systems. They could diagnose and give you a price on a rebuild if it is confirmed as diff. Might be a lot cheaper than £4K!! i would be very interested if you followed up on here on the cause and fix though please. Every day is a school day for sure!! But my 50p bet is still not on the diff, but I am not willing to bet any higher! Lol

Hey Nick, Are you 100% sure it’s the diff? Have you looked for wear in the drive shafts ETC. Not common for a diff to give up the ghost these days unless they have run out of oil. Have you been told it’s the diff?