Zuban's 2007 Audi Q7 4.2TDI - Test your limits and carry on
Discussion
About three years ago give or take a few days, I chose to sell my lovely 2018 Audi A4 Avant, it was a really nice spec, quantum grey, tech pack etc, I chose to sell it for a number of reasons, the 1.4t engine wasn't an issue, the car was great,
I had a three year old daughter, and a second new one had just arrived. Seemed ideal, until a few events happened, my wife was complaining about the space inside the car on days out working round everything we needed to take and feeding, and more significantly one day she drove it off a small cliff (a small gap entering an unfinished car park) and grounded it out needing me and my dad to work it out of there with trolley jacks and spades. Then my 3 year old jammed a door between two fence panels when opening it.
There was also that time my wife asked me to go collect some pallets ( in a sea of being asked to collect random things off Facebook market place that would never fit), that apparently would definitely fit in the boot, that really did not.
I took the decision to let Audi buy the car back rather than having it slowly destroyed by my family, it was at the point the second hand car market went mad and I went from no equity to within 6 months having enough to get out quite happy that I had not lost too much.
Being a fan of the Audi brand, reasonably handy and comfortable working on cars, and really quite naïve when it comes to VAG products, I thought a larger Audi SUV might be a good idea, if the kids damage it i wont mind so much, no chance the wife will beach this one.
I researched it and found when it came to the Q7, the 4.2TDI engine was the pick of the bunch, So I did the sensible thing and got on a plane and bought the cheapest 4.2 V8 TDI I could find in the country.
It should be noted at this point, I live less than 10 minutes walk from the kids nursery/school, and a shop. So we choose not to take the car a lot, and its not really a big deal if we cant short term.
Coming back to the flight down from Inverness to Birmingham to collect the car, looking back things have never been smooth, the wind was high during landing, and the left wing of the plane was uncomfortably close to being in the dirt but the pilot caught it in a violent manoeuvre. Then I was scammed by a taxi driver who drove me about the place going in wrong directions, I paid by card, he claimed it had not gone through, and charged me cash, only for me to get the card charge a month later.
I can see why people say don't buy a car from Birmingham.
Anyway got to the garage in the end, the Q7 was sound, had body work blemishes not unusual for a car of its age, but was mechanically sound (at that point in time anyway ) . It had just had new brakes, new suspension compressor, fresh service, and came with a years warranty. Drove well and everything worked as it should.
So I left on the roughly 450 mile journey home. All good, the Q7 worked as it should, but the weather did not, there was torrential rain, probably the worst rain have experienced, on a three lane motorway, visibility was very poor and progress slow, you could hardly see the lane markers, and I know I drove over something that had been dislodged from another car, was worried i'd picked up a puncture, but it wasn't until a bit later the rear left tyre blew out. To its credit the Q7 remained stable, the noise from the rear was terrible, and the dashboard lit up, but I was able to pull it off the motorway around 10pm and assess what had happened. I managed to limp the further 100m or so to the Premier inn in Penrith.
At the time of the blowout, I had passed the storm weather and was sitting at motorway speeds, I don't know if its the way air suspension works, but there was no drama, I was able to reduce speed and get off the motorway at the next junction.
Unplanned overnight stay done, I got up just after 7am, used the compressor that comes with the car to inflate the compact spare and fit it, and arrived at a local tyre fitter for opening time, they got me in straight away and I was back on my way.
It had been a while since I had a car that could overtake slower vehicles well, and coming up the A9 it was certainly useful having a surprising turn of speed available in a vehicle so large and heavy.
Fast forward a while, the Q7 has been great, carrying book cases, buggies, dump runs, every time a kid opens the door into a wall or fence, i don't mind, it has plastic covers on the bottom of the doors. I drove into a fence by accident once parking at B&Q, didn't even expend the energy to shrug it off.
That's when things start to get tough again, its an older car, coming up for 150k miles, I know it will need some work. I'm fine with that and thought I was prepared. I've built a few track cars over the years and do my own work, false sense of security...
One of the first problems is it doesn't want to start occasionally, not very often just every now and again, also every now and again it goes into limp mode and cuts power, then randomly comes out of it and is fine again. A sign of things to come.
Both of these things are starting to get worse over time, the not starting is fairly obvious the starter motor needs changed, so I purchased a refurb unit and plan to do it.
Meanwhile the limp mode issue has been going on for some time, I have a VCDS unit and have been trying to figure out what the issue is but keep hitting dead ends ( more on that later ).
I took the car to a garage to find out what it would cost for them to fit a new starter motor as I was busy at the time and struggling to find time. When I left the garage after them saying they would be weeks before they could look at it, the car would not start at all, not even try.
I had the car recovered the next day, and set about it. Turns out various Audi's of that age have a similar steering lock system that uses microswitches which can fail over time, so I stripped the dash back, and removed the steering lock ecu and sent it off to be recoded, and have the lock removed altogether, put it back together and the car was running again. Hopefully for the problem to never re-occur. Cost was about £300.
So back to the other problems, after an angry phone call from the wife who couldn't start the car up at the school, only for me to go up and find she was trying to start it with the autobox in D, I put it in P and it started first time but never mind I decided it was time to change the starter motor. This is what it takes to change a 4.2TDI starter motor on a driveway.
Whilst I was at it, i changed the DPF pressure sensors, oh did I mention I was having DPF issues and couldn't do a regen.
Ok, so once the starter and DPF sensors were changed, the car started every time no problem, however it was in permanent limp mode... great.
So got the VCDS unit out, I had been trying to figure out this issue which was a turbo actuator control issue for months. There was a point of revelation, the ODBII codes note which bank of the V as one either 1 or 2, and the VAG group codes mark each bank as 1 or 2, both Audi and the ODB standards refer to as the opposite, so I'd been going off the ODBII codes and the problem turbo was actually on the opposite side of the engine
15 minutes later i'd found the turbo actuator wiring loom on the side with an actual problem, I had been looking at and testing the wrong side the entire time, it had a wiring issue where one of the 5 wires had corroded to the point it was making bad connection up until I disturbed things and then it had no connection. A £15 replacement connector spliced on and the problem was gone. I took a moment in-between to get rid of the DPF problem for good, and have the ECU's remapped ( approx 380bhp and 620fl lb ). All of that probably cost me around £700
Just realised I missed the bit where my wife took the car to college on a snowy day and it died because one of the two ecu's got flooded, that was the first time it was recovered, and cost me £800 getting a new ecu programmed. The ecu sits under the front right scuttle panel, a common issue, the replacement has a cap on it to protect it going forward.
Other fun parts are, one of the wiper blades snapped off when my wife was driving it, another common fault, so that was replaced. The wipers randomly stopped working, a lot. Turns out new linkages etc for right hand models require a re-mortgage. I eventually just opened up the original motor assembly and found a spring washer had broke in half locking it up, took it out and its been fine since. I'm really good at removing and refitting Q7 wipers now.
Most of that was in the first 18 months of owning it, the car was fine when I picked it up honestly gov, just seem to have timed things so everything that could go wrong would go wrong in that time frame, its been fine since. The last MOT needed a wheel bearing and the Brembo front brake link pipes changed which I did myself.
Just prior to the MOT it hauled my Clio on trailer up to a track day which is one of the reasons I originally bought the car, was good to finally do that.
There is no doubt smaller issues I've missed out, I love this car despite what its put me through, its carried insane amount of stuff in its cavern, it goes through snow like it doesn't exist ( I live above the snowline ), and the kids love shouting "spppeeeeed" when they want to be shoved into the back of their seats.
As a footnote, the cars based on this platform aka the Q7, cayenne and treg mk 1's are becoming increasingly popular as the price of them reduces. Aftermarket support is getting better all the time. When i had the front subframe off I used Eurowise front subframe cantering bushes, and will fit the rears when the time comes. I replaced the front wishbone bushes with powerflex items and will continue upgrade where suitable as I replace.
I had a three year old daughter, and a second new one had just arrived. Seemed ideal, until a few events happened, my wife was complaining about the space inside the car on days out working round everything we needed to take and feeding, and more significantly one day she drove it off a small cliff (a small gap entering an unfinished car park) and grounded it out needing me and my dad to work it out of there with trolley jacks and spades. Then my 3 year old jammed a door between two fence panels when opening it.
There was also that time my wife asked me to go collect some pallets ( in a sea of being asked to collect random things off Facebook market place that would never fit), that apparently would definitely fit in the boot, that really did not.
I took the decision to let Audi buy the car back rather than having it slowly destroyed by my family, it was at the point the second hand car market went mad and I went from no equity to within 6 months having enough to get out quite happy that I had not lost too much.
Being a fan of the Audi brand, reasonably handy and comfortable working on cars, and really quite naïve when it comes to VAG products, I thought a larger Audi SUV might be a good idea, if the kids damage it i wont mind so much, no chance the wife will beach this one.
I researched it and found when it came to the Q7, the 4.2TDI engine was the pick of the bunch, So I did the sensible thing and got on a plane and bought the cheapest 4.2 V8 TDI I could find in the country.
It should be noted at this point, I live less than 10 minutes walk from the kids nursery/school, and a shop. So we choose not to take the car a lot, and its not really a big deal if we cant short term.
Coming back to the flight down from Inverness to Birmingham to collect the car, looking back things have never been smooth, the wind was high during landing, and the left wing of the plane was uncomfortably close to being in the dirt but the pilot caught it in a violent manoeuvre. Then I was scammed by a taxi driver who drove me about the place going in wrong directions, I paid by card, he claimed it had not gone through, and charged me cash, only for me to get the card charge a month later.
I can see why people say don't buy a car from Birmingham.
Anyway got to the garage in the end, the Q7 was sound, had body work blemishes not unusual for a car of its age, but was mechanically sound (at that point in time anyway ) . It had just had new brakes, new suspension compressor, fresh service, and came with a years warranty. Drove well and everything worked as it should.
So I left on the roughly 450 mile journey home. All good, the Q7 worked as it should, but the weather did not, there was torrential rain, probably the worst rain have experienced, on a three lane motorway, visibility was very poor and progress slow, you could hardly see the lane markers, and I know I drove over something that had been dislodged from another car, was worried i'd picked up a puncture, but it wasn't until a bit later the rear left tyre blew out. To its credit the Q7 remained stable, the noise from the rear was terrible, and the dashboard lit up, but I was able to pull it off the motorway around 10pm and assess what had happened. I managed to limp the further 100m or so to the Premier inn in Penrith.
At the time of the blowout, I had passed the storm weather and was sitting at motorway speeds, I don't know if its the way air suspension works, but there was no drama, I was able to reduce speed and get off the motorway at the next junction.
Unplanned overnight stay done, I got up just after 7am, used the compressor that comes with the car to inflate the compact spare and fit it, and arrived at a local tyre fitter for opening time, they got me in straight away and I was back on my way.
It had been a while since I had a car that could overtake slower vehicles well, and coming up the A9 it was certainly useful having a surprising turn of speed available in a vehicle so large and heavy.
Fast forward a while, the Q7 has been great, carrying book cases, buggies, dump runs, every time a kid opens the door into a wall or fence, i don't mind, it has plastic covers on the bottom of the doors. I drove into a fence by accident once parking at B&Q, didn't even expend the energy to shrug it off.
That's when things start to get tough again, its an older car, coming up for 150k miles, I know it will need some work. I'm fine with that and thought I was prepared. I've built a few track cars over the years and do my own work, false sense of security...
One of the first problems is it doesn't want to start occasionally, not very often just every now and again, also every now and again it goes into limp mode and cuts power, then randomly comes out of it and is fine again. A sign of things to come.
Both of these things are starting to get worse over time, the not starting is fairly obvious the starter motor needs changed, so I purchased a refurb unit and plan to do it.
Meanwhile the limp mode issue has been going on for some time, I have a VCDS unit and have been trying to figure out what the issue is but keep hitting dead ends ( more on that later ).
I took the car to a garage to find out what it would cost for them to fit a new starter motor as I was busy at the time and struggling to find time. When I left the garage after them saying they would be weeks before they could look at it, the car would not start at all, not even try.
I had the car recovered the next day, and set about it. Turns out various Audi's of that age have a similar steering lock system that uses microswitches which can fail over time, so I stripped the dash back, and removed the steering lock ecu and sent it off to be recoded, and have the lock removed altogether, put it back together and the car was running again. Hopefully for the problem to never re-occur. Cost was about £300.
So back to the other problems, after an angry phone call from the wife who couldn't start the car up at the school, only for me to go up and find she was trying to start it with the autobox in D, I put it in P and it started first time but never mind I decided it was time to change the starter motor. This is what it takes to change a 4.2TDI starter motor on a driveway.
Whilst I was at it, i changed the DPF pressure sensors, oh did I mention I was having DPF issues and couldn't do a regen.
Ok, so once the starter and DPF sensors were changed, the car started every time no problem, however it was in permanent limp mode... great.
So got the VCDS unit out, I had been trying to figure out this issue which was a turbo actuator control issue for months. There was a point of revelation, the ODBII codes note which bank of the V as one either 1 or 2, and the VAG group codes mark each bank as 1 or 2, both Audi and the ODB standards refer to as the opposite, so I'd been going off the ODBII codes and the problem turbo was actually on the opposite side of the engine
15 minutes later i'd found the turbo actuator wiring loom on the side with an actual problem, I had been looking at and testing the wrong side the entire time, it had a wiring issue where one of the 5 wires had corroded to the point it was making bad connection up until I disturbed things and then it had no connection. A £15 replacement connector spliced on and the problem was gone. I took a moment in-between to get rid of the DPF problem for good, and have the ECU's remapped ( approx 380bhp and 620fl lb ). All of that probably cost me around £700
Just realised I missed the bit where my wife took the car to college on a snowy day and it died because one of the two ecu's got flooded, that was the first time it was recovered, and cost me £800 getting a new ecu programmed. The ecu sits under the front right scuttle panel, a common issue, the replacement has a cap on it to protect it going forward.
Other fun parts are, one of the wiper blades snapped off when my wife was driving it, another common fault, so that was replaced. The wipers randomly stopped working, a lot. Turns out new linkages etc for right hand models require a re-mortgage. I eventually just opened up the original motor assembly and found a spring washer had broke in half locking it up, took it out and its been fine since. I'm really good at removing and refitting Q7 wipers now.
Most of that was in the first 18 months of owning it, the car was fine when I picked it up honestly gov, just seem to have timed things so everything that could go wrong would go wrong in that time frame, its been fine since. The last MOT needed a wheel bearing and the Brembo front brake link pipes changed which I did myself.
Just prior to the MOT it hauled my Clio on trailer up to a track day which is one of the reasons I originally bought the car, was good to finally do that.
There is no doubt smaller issues I've missed out, I love this car despite what its put me through, its carried insane amount of stuff in its cavern, it goes through snow like it doesn't exist ( I live above the snowline ), and the kids love shouting "spppeeeeed" when they want to be shoved into the back of their seats.
As a footnote, the cars based on this platform aka the Q7, cayenne and treg mk 1's are becoming increasingly popular as the price of them reduces. Aftermarket support is getting better all the time. When i had the front subframe off I used Eurowise front subframe cantering bushes, and will fit the rears when the time comes. I replaced the front wishbone bushes with powerflex items and will continue upgrade where suitable as I replace.
Edited by Zuban on Tuesday 15th October 00:46
Edited by Zuban on Tuesday 15th October 00:48
A cool car OP, good effort going for the V8 diesel over the V6 diesel - both suit a car like this I'd imagine! Hows the V8 in this in general for risk? I see the V10 & V12 Dervs in some of the other VAG offerings, and they seem a bit scary mostly due to a lack of access to change any parts.
I had a Touareg with that engine for a couple of years. Seems I got lucky as it needed nothing other than a service. That engine and an auto box is a great combo for a heavy SUV.
From what I gather there's virtually no difference in fuel economy between the V6 and V8.
£700+ on VED was the reason I got rid of it in the end, just grated a bit too much.
From what I gather there's virtually no difference in fuel economy between the V6 and V8.
£700+ on VED was the reason I got rid of it in the end, just grated a bit too much.
When I researched before I bought it, it seemed the V8 was generally considered to have less issues than the V6, and was a better match for the car.
I've just done an oil service on the engine, so far the engine itself has been fine, runs very nicely. Its mostly been issues with the electrics I've had.
There was a couple other things I'd forgotten I'd replaced, one of the power steering pipes started leaking, so replaced that, the second pipe has started weeping very slightly so its now on the to do list.
I don't think its the type of car anyone should own unless your fairly competent with mechanics and have the tools, or your happy paying more than the cars worth to a garage to fix it.
I've just done an oil service on the engine, so far the engine itself has been fine, runs very nicely. Its mostly been issues with the electrics I've had.
There was a couple other things I'd forgotten I'd replaced, one of the power steering pipes started leaking, so replaced that, the second pipe has started weeping very slightly so its now on the to do list.
I don't think its the type of car anyone should own unless your fairly competent with mechanics and have the tools, or your happy paying more than the cars worth to a garage to fix it.
Nice car, I don't see many about these days.
Your pictures gave me flashbacks to the time I replaced the starter motor on my 2003 Touareg petrol V8 - the hardest job I have undertaken on any car so far. Unless you're handy with the spanners these cars are an economic write-off for most people. On the flip side you can pick them up cheaply.
Enjoy. Always good to see someone getting properly stuck in and saving a car from the scrappers.
Your pictures gave me flashbacks to the time I replaced the starter motor on my 2003 Touareg petrol V8 - the hardest job I have undertaken on any car so far. Unless you're handy with the spanners these cars are an economic write-off for most people. On the flip side you can pick them up cheaply.
Enjoy. Always good to see someone getting properly stuck in and saving a car from the scrappers.
Blimey! Recently bought a Cayenne S with the 4.2 V8 diesel engine. It had the starter motor changed before I picked it up as when I viewed it the starter was a little lazy Glad it was done having seen those photos of what it takes to change it.
The combination of torque/power/speed and yet the fuel economy of 34mpg in mixed driving is incredible.
The combination of torque/power/speed and yet the fuel economy of 34mpg in mixed driving is incredible.
DanG355 said:
Blimey! Recently bought a Cayenne S with the 4.2 V8 diesel engine. It had the starter motor changed before I picked it up as when I viewed it the starter was a little lazy Glad it was done having seen those photos of what it takes to change it.
The combination of torque/power/speed and yet the fuel economy of 34mpg in mixed driving is incredible.
Yeah it was a big job, having done it once now, I'd be able to do it again in a fraction of the time it took the first time, although I would rather not have to!The combination of torque/power/speed and yet the fuel economy of 34mpg in mixed driving is incredible.
I've found if just doing some short runs for a while without a decent run, it helps to give the battery an occasional charge using the charging posts in the engine bay. A v8 high compression diesel engine takes a fair draw of power to get going, especially when cold, I've found if the weathers bad and its being used for the school run, because we live so close to the school, within a couple of weeks the battery needs a charge as it just doesn't get enough from the short runs.
I also think mine will need an alternator at some point, its towards the lower end of voltage when running at 13.7 volts
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