Captdave

Hi Guys, Just put my car through its ITV or MOT to you boys and it failed for Lights, emissions and brakes its a 2004 A6C5 Avant quattro 2.5 tdi with 206,000 kms. Lets deal with the emissions first I had changed the EGR valve a few months ago but I noticed my engine light had come back on recently. I managed to turn it off with an OBD reader(fault being insufficient exhaust gas recirculation) but it failed the emissions test anyway so I thought I had better have a look. It transpires that the valve was opening OK but actually lifting up the valve seat at the same time so no exhaust gas was able to circulate hence the yellow light on again. I fixed the valve by securing the valve seat so it could not move (drilled and tapped with grub screw) and bingo after reassembly and running for 10 mins or so out went the engine warning light, great, so back to the local testing station where the car failed again for emissions (to much smoke) which I have to say was a little disappointing. So I had a look around on the internet for anti smoke treatments etc but while looking I found a brilliant article on this very topic by Highmotor. In the article he suggests that if your car only does short trips (like mine) it can lead to a build up of soot in the exhaust sufficient to fail the test and his solution is TO RUN THE CAR FOR ABOUT 30 KMS IN A LOW GEAR AT MAXIMUM REVS ON THE MOTORWAY TO BLOW OUT ALL THE SOOT. I thought I would give this a try and so this time I went to a testing station about 40 kms up the road in 3rd gear at 4000 rpm and the car passed no problem at all. So before you try any other cures and treatments give that a go it might be obvious to some people but it was not to me I was thinking injector change which is very expensive. My car also failed for brakes so I had a look at them, the rear the pads and discs were very very worn so I changed them and back I went to the ITV station where it failed again for brakes being inefficient. I knew the brakes were fine (being a retired mechanic) handbrake was very effective and while driving the car stopped perfectly so I had a cunning plan. A few years ago my motorhome would not pass the brake test whatever I did and I did a lot over several months until finally one of the technicians at the testing station sort of implied the motorhome might need more weight in it to pass. So next time I went for the test I loaded the camper with my motorbike on the back and my pal sitting in the toilet and it passed easily. There never was anything wrong with the brakes just the way their stupid rolling road works. So next time I went to the testing station with the Audi I put about 5 jerry cans filled with water and two large gas bottles in the back and hey presto car passed with flying colours along with the emissions. The lights were an easy fix if a bit tedious. My car had a plastic sort of film covering the headlights and this had started to degenerate and peel off in places. The cure was to attack it with plastic scrappers and varying grades of sand paper (400 to 2000) until all the film was removed and then polish them with a machine so they came up great and passed the test easily. So I hope this helps some of you pass your MOT or ITV test its good to pass on some useful tips to like minded souls I think anyway. Bye for now Captdave

Hi Steve, Yes it is possible to clean the EGR valve, I did mine with brake cleaner rags and a tooth brush and its quite easy however you should test it with a little vacuum pump to make sure it holds pressure (mine did not)

Not so long ago the engine management light (EML) was on most of the time on my 2004 2.5 TDI C5 allroad. It would go off occasionally but would very soon come back on again. I tested it with my Launch OBD11 reader and it came up with the following faults PO401 and P0402. P0401 means insufficient exhaust gas recirculation P0402 means excessive exhaust gas recirculation So having some idea of what the problem was I decided to carry out a few tests around and on the EGR valve. First test I did was to check I had a vacuum going to the EGR valve. I did this by getting the car warm and then pulling off the vacuum pipe and putting my finger over the end and it had a good suction. Next test was to disconnect the electric plug to the EGR Solenoid valve (this is controlled by the ECU and tells the Solenoid valve when to open and supply vacuum to the EGR valve) With the plug disconnected no vacuum at the end of the pipe so that proved the solenoid valve was working as it should. Third test was to use a little vacuum tester (20 euro from Amazon) on the EGR valve itself. I found the EGR valve was unable to hold a vacuum at all and rapidly returned the gauge to zero telling me that the diaphragm inside the EGR valve was faulty. The next step was to order a new EGR valve from Autodoc and proceed to change the valve which at first sight looks a bit tricky but it is quite straightforward once you get into it. TOP TIP to remove the two allen headed set screws you will need a six mm allen key on a socket I used a quarter inch square drive allen Key with a very small extension around 2 inches otherwise you will really struggle to get the screws out. You will need to remove the Turbo heat shield first which is only help in place by a couple of screws. Once the allen screws are out you need to remove the inlet manifolds so you can gain access to the two 13mm bolts that hold the EGR valve onto the bypass pipe. They come off very easily again with a socket driven allen key and extension. Now you need a 13mm combination spanner to undo the two 13mm bolts you may need to twist the EGR valve a little to get at them and off it comes. At this point I used my vacuum tester on the new EGR valve which help the pressure perfectly where the old one would just open and then close straight away. To my horror I discovered there was a real filthy mess inside the inlet manifolds and inlet ports on the cylinder heads in some cases restricting the flow by around 40 percent YES 40 percent at least. So I had to clean all this mess out and this is a dirty filthy horrible job. I used brake cleaner and rags in my garage but still made a hell of a mess much better to do it in a parts washer or take it to the car pressure wash YOU HAVE BEEN WARNED. When it is all cleaned up you can reassemble in the reverse order which does not take long and give it a try. My EML light did not go out straight away but after a few minutes before I even got the car out of the garage it was off and has not been back on since so a great result. Incidentally the car has never run better which is unsurprising considering all the gunk that was in the manifolds and the EGR valve being unserviceable. Hope this helps I was just a bit bored today so thought I would post about my EGR valve work. All The Best Capt Dave

While doing the cam belts l noticed the gearbox oil cooler is connected to the radiator so there is a seperate circuit within the radiator that further cools the gearbox oil which l found a bit strange. The gearbox oil comes from the gearbox to its own little cooler then from the cooler to the main radiator then back to the cooler and returns to the gearbox. I found this strange but l am sure there is a very good reason for it other than making it very awkward to remove and refit the radistor.

The cambelt waterpump and thermostat are all changed along with all the various pulleys and adjusters. You dont really need the special tools if you carefully mark all the pulleys with tipex or similar. I also did the valve cover gaskets which were leaking badly and changed the o rings in the radiator top and bottom hose. You do need to lock the fuel pump pulley but that is easy to do with something that fits in the hole like a drill or parallel punch. The engine was filthy from all the oil leaks and that took a time to clean. I also checked the camshaft oil seals but they were fine and didnt need changed. I got most of the spares from Autodoc who have been super and l cant recommend them highly enough. Its quite a big job but if you work away steadily you will get there l am 73 and a retired mechanic my non mechanic mate is 75 but we managed fine it took a few days in my garage but the end result is really good. My non mechanic mate is !Removed! good at bodywork so he did some great work on a couple of dents and scratches. Wisshing you all a happy Christmas and great New Year and thanks for your help so far. Capt Dave

Anybody had problems with the gearbox oil cooler heat exchanger if you like. I think mine may be leaking oil into the coolant. Just doing a cambelt change among other things and noticed what looks like transmisión fluid in the coolant on striping it all down. Just wondering if any body else has had this problem.

Any thoughts on changing the led cluster language to English.

Turns out it was a faulty LED in the cluster all working great now after sending away for repair.

Hi Guys, My A6 C5 allroad is up and running and l am really pleased with it. I have renewed the front wheel bearings which were very noisy and sent the instrument cluster away for repair which now works beautifully. My problem now is its all in Spanish and l would like to change the display to English but l may have a knob missing as l have no knob to access the menu which should be on the central console but it aint so does anybody know if it should be there (the knob) or is my model different and can be adjusted in another way. Cheery Bye Capt Dave

Getting ready to do a cam belt change on my 2.5 tdi All Road from 2004 does anybody have any experience of changing the belt without the reqd tools or better still anybody have the tools reqd l can borrow buy or hire. I will be doing the front wheel bearings as soon as the spares arrive looks like l will need a big press for that job as well unless you guys kmow different. Cheers Capt Dave Quote

Hi Guys finally l have my A6 Allroad on the road and its great however l have a problem with the LH indicator warning light in the instrument cluster. Is this just a light bulb that can be changed or is it a major drama having watched a few videos it seems easy enough to take out the instrument panel but l cant see any bulb holders. Anybody else has this problem Cheers

Thats great thanks for that David

Yes sorry l realised that after l pressed post not to worry.

Just received your message it didnt come up on email so do you still have it then.

I dont suppose you still have this will it fit my 2004 A6 C5 avant